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  • 1.
    Abdel-Magied, Ahmed F.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shatskiy, Andrey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Arafa, Wael A. A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. University Fayoum, Egypt.
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Bjorn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Chemical and Photochemical Water Oxidation Mediated by an Efficient Single-Site Ruthenium Catalyst2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 24, s. 3448-3456Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water oxidation is a fundamental step in artificial photosynthesis for solar fuels production. In this study, we report a single-site Ru-based water oxidation catalyst, housing a dicarboxylate-benzimidazole ligand, that mediates both chemical and light-driven oxidation of water efficiently under neutral conditions. The importance of the incorporation of the negatively charged ligand framework is manifested in the low redox potentials of the developed complex, which allows water oxidation to be driven by the mild one-electron oxidant [Ru(bpy)(3)](3+) (bpy = 2,2'-bipyridine). Furthermore, combined experimental and DFT studies provide insight into the mechanistic details of the catalytic cycle.

  • 2. Anugwom, Ikenna
    et al.
    Eta, Valerie
    Virtanen, Pasi
    Mäki-Arvela, Päivi
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hummel, Michael
    Sixta, Herbert
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Switchable ionic liquids as delignification solvents for lignocellulosic materials2014Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, nr 4, s. 1170-1176Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The transformation of lignocellulosic materials into potentially valuable resources is compromised by their complicated structure. Consequently, new economical and feasible conversion/fractionation techniques that render value-added products are intensely investigated. Herein an unorthodox and feasible fractionation method of birch chips (B. pendula) using a switchable ionic liquid (SIL) derived from an alkanol amine (monoethanol amine, MEA) and an organic super base (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) with two different trigger acid gases (CO2 and SO2 ) is studied. After SIL treatment, the dissolved fractions were selectively separated by a step-wise method using an antisolvent to induce precipitation. The SIL was recycled after concentration and evaporation of anti-solvent. The composition of undissolved wood after MEA-SO2 -SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA-CO2 -SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA-SO2 -SIL proved more efficient than the MEA-CO2 -SIL, and a better solvent for lignin removal. All fractions were analyzed by gas chromatography (GC), Fourier transform infrared spectroscopy (FT-IR), (13) C nuclear magnetic resonance spectroscopy (NMR) and Gel permeation chromatography (GPC).

  • 3. Beller, M.
    et al.
    Centi, G.
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Chemistry Future: Priorities and Opportunities from the Sustainability Perspective2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 1, s. 6-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To celebrate the 10 year anniversary of ChemSusChem, we as the chairmen of the editorial board are writing this Essay to summarize important scientific contributions to our journal during the past decade in terms of sustainable science and technology. Bibliometric analysis of published papers show that biorefinery, solar energy conversion, energy-storage materials, and carbon dioxide utilizations attracted most attention in this area. According to our own knowledge and understanding and from the sustainability point of view, we are also pointing out those research directions that we believe can play key roles in the future chemistry to meet the grand challenges in energy and environment. Hopefully, these perspective aspects will provide the readers with new angles to look at the chemistry in the coming decades and inspire the development of new technologies to make our society sustainable.

  • 4.
    Björnerbäck, Fredrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Highly Porous Hypercrosslinked Polymers Derived from Biobased Molecules2019Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, nr 4, s. 839-847Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Highly porous and hyper-cross-linked polymers (HCPs) have a range of applications and are typically synthesized in an unsustainable manner. Herein, HCPs were synthesized from abundant biobased or biorelated compounds in sulfolane with iron(III) chloride as Lewis acid catalyst. As reactants, quercetin, tannic acid, phenol, 1,4-dimethoxybenzene, glucose, and a commercial bark extract were used. The HCPs had high CO2 uptake (up to 3.94 mmol g(-1) at 0 degrees C and 1 bar), total pore volumes (up to 1.86 cm(3) g(-1)), and specific surface areas (up to 1440 m(2) g(-1)). H-1 NMR, C-13 NMR, and IR spectroscopy, wide-angle X-ray scattering, elemental analysis, and SEM revealed, for example, that the HCPs consisted of amorphous and cross-linked aromatic and phenolic structures with significant contents of aliphatics, oxygen, and sulfur.

  • 5. Budarin, Vitaliy L
    et al.
    Clark, James H
    Henschen, Jonatan
    Farmer, Thomas J
    Macquarrie, Duncan J
    Mascal, Mark
    Nagaraja, Gundibasappa K
    Petchey, Tabitha H M
    Processed Lignin as a Byproduct of the Generation of 5-(Chloromethyl)furfural from Biomass: A Promising New Mesoporous Material.2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 24, s. 4172-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The lignin by-product of the conversion of lignocellulosic biomass to 5-(chloromethyl)furfural (CMF) has been characterised by thermogravimetric analysis, N2 physisorption porosimetry, attenuated internal reflectance IR spectroscopy, elemental analysis and solid-state NMR spectroscopy. The lignin (LCMF) has a moderate level of mesoporosity before thermal treatment and a surface area of 63 m(2)  g(-1) , which increases dramatically on pyrolysis at temperatures above 400 °C. An assessment of the functionality and textural properties of the material was achieved by analysing LCMF treated thermally over a range of pyrolysis temperatures. Samples were sulfonated to test their potential as heterogeneous acid catalysts in the esterification of levulinic acid. It was shown that unpyrolysed catalysts gave the highest ester yields of up to 93 %. To the best of our knowledge, this is the first example of mesoporous lignin with an appreciable surface area that is produced directly from a bio-refinery process and with further textural modification of the material demonstrated.

  • 6. Chen, Cheng
    et al.
    Yang, Xichuan
    Cheng, Ming
    Zhang, Fuguo
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    Degradation of Cyanoacrylic Acid-Based Organic Sensitizers in Dye-Sensitized Solar Cells2013Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, nr 7, s. 1270-1275Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Organic dyes have become widely used in dye-sensitized solar cells (DSSCs) because of their good performance, flexible structural modifications, and low costs. To increase the photostability of organic dye-based DSSCs, we conducted a full study on the degradation mechanism of cyanoacrylic acid-based organic sensitizers in DSSCs. The results showed that with the synergy between water and UV light, the sensitizer could desorb from the TiO2 surface and the cyanoacrylic acid unit of the sensitizer was transformed into the aldehyde group. It was also observed that the water content had a great effect on the degradation process. Our experiments conducted using O-18-labeled water demonstrated that the oxygen atom of the aldehyde group identified in the degraded dye came from the solvent water in the DSSCs. Therefore, controlling the water content during DSSC fabrication, good sealing of cells, and filtering the UV light are crucial to produce DSSCs that are more durable and robust.

  • 7. Chen, Hu
    et al.
    Gao, Yan
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. Dalian Univ Technol, Peoples R China.
    Highly Active Three-Dimensional NiFe/Cu2O Nanowires/Cu Foam Electrode for Water Oxidation2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 7, s. 1475-1481Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water splitting is of paramount importance for exploiting renewable energy-conversion and -storage systems, but is greatly hindered by the kinetically sluggish oxygen evolution reaction (OER). In this work, a three-dimensional, highly efficient, and durable NiFe/Cu2O nanowires/Cu foam anode (NiFe/Cu2O NWs/CF) for water oxidation in 1.0m KOH was developed. The obtained electrode exhibited a current density of 10mAcm(-2) at a uniquely low overpotential of =215mV. The average specific current density (j(s)) was estimated, on the basis of the electrocatalytically active surface area, to be 0.163mAcm(-2) at =310mV. The electrode also displayed a low Tafel slope of 42mVdecade(-1). Moreover, the NiFe/Cu2O NWs/CF electrode could maintain a steady current density of 100mAcm(-2) for 50h at an overpotential of =260mV. The outstanding electrochemical performance of the electrode for the OER was attributed to the high conductivity of the Cu foam and the specific structure of the electrode with a large interfacial area.

  • 8. Cheng, Ming
    et al.
    Yang, Xichuan
    Zhao, Jianghua
    Chen, Cheng
    Tan, Qin
    Zhang, Fuguo
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    Efficient Organic Dye-Sensitized Solar Cells: Molecular Engineering of Donor-Acceptor-Acceptor cationic dyes2013Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, nr 12, s. 2322-2329Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Three metal-free donor-acceptor-acceptor sensitizers with ionized pyridine and a reference dye were synthesized, and a detailed investigation of the relationship between the dye structure and the photophysical and photoelectrochemical properties and the performance of dye-sensitized solar cells (DSSCs) is described. The ionization of pyridine results in a red shift of the absorption spectrum in comparison to that of the reference dye. This is mainly attributable to the ionization of pyridine increasing the electron-withdrawing ability of the total acceptor part. Incorporation of the strong electron-withdrawing units of pyridinium and cyano acrylic acid gives rise to optimized energy levels, resulting in a large response range of wavelengths. When attached to TiO2 film, the conduction band of TiO2 is negatively shifted to a different extent depending on the dye. This is attributed to the electron recombination rate between the TiO2 film and the electrolyte being efficiently suppressed by the introduction of long alkyl chains and thiophene units. DSSCs assembled using these dyes show efficiencies as high as 8.8%.

  • 9.
    Cong, Jiayan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Hao, Yan
    Boschloo, Gerrit
    Kloo, Lars
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Electrolytes Based on TEMPO-Co Tandem Redox Systems Outperform Single Redox Systems in Dye-sensitized Solar Cells2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 2, s. 264-268Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new TEMPO-Co tandem redox system with TEMPO and Co(bpy)(3)(2+/3+) has been investigated for the use in dye-sensitized solar cells (DSSCs). A large open-circuit voltage (V-OC) increase, from 862 mV to 965 mV, was observed in the tandem redox system, while the short-circuit current density (J(SC)) was maintained. The conversion efficiency was observed to increase from 7.1% for cells containing the single Co(bpy)(3)(2+/3+) redox couple, to 8.4% for cells containing the TEMPO-Co tandem redox system. The reason for the increase in V-OC and overall efficiency is ascribed to the involvement of partial regeneration of the sensitizing dye molecules by TEMPO. This assumption can be verified through the observed much faster regeneration dynamics exhibited in the presence of the tandem system. Using the tandem redox system, the faster recombination problem of the single TEMPO redox couple is resolved and the mass-transport of the metal-complex-based electrolyte is also improved. This TEMPO-Co tandem system is so far the most effienct tandem redox electrolyte reported not involving iodine. The current results show a promising future for tandem system as replacements for single redox systems in electrolytes for DSSCs.

  • 10. Cong, Jiayan
    et al.
    Hao, Yan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Boschloo, Gerrit
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Kloo, Lars
    Electrolytes Based on TEMPO-Co Tandem Redox Systems Outperform Single Redox Systems in Dye-sensitized Solar Cells2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 2, s. 264-268Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new TEMPO-Co tandem redox system with TEMPO and Co(bpy)(3)(2+/3+) has been investigated for the use in dye-sensitized solar cells (DSSCs). A large open-circuit voltage (V-OC) increase, from 862 mV to 965 mV, was observed in the tandem redox system, while the short-circuit current density (J(SC)) was maintained. The conversion efficiency was observed to increase from 7.1% for cells containing the single Co(bpy)(3)(2+/3+) redox couple, to 8.4% for cells containing the TEMPO-Co tandem redox system. The reason for the increase in V-OC and overall efficiency is ascribed to the involvement of partial regeneration of the sensitizing dye molecules by TEMPO. This assumption can be verified through the observed much faster regeneration dynamics exhibited in the presence of the tandem system. Using the tandem redox system, the faster recombination problem of the single TEMPO redox couple is resolved and the mass-transport of the metal-complex-based electrolyte is also improved. This TEMPO-Co tandem system is so far the most effienct tandem redox electrolyte reported not involving iodine. The current results show a promising future for tandem system as replacements for single redox systems in electrolytes for DSSCs.

  • 11.
    Das, Biswanath
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Orthaber, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Thapper, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Iron Pentapyridyl Complexes as Molecular WaterOxidation Catalysts: Strong Influence of a Chloride Ligandand pH in Altering the Mechanism2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 10, s. 1178-1186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of molecular water oxidation catalysts basedon earth-abundant, non-noble metals is essential for artificial photosynthesis research. Iron, which is the most abundant transition metal in the earth's crust, is a prospective candidate for this purpose. Herein, we report two iron complexes based on the polypyridyl ligand Py5OH (Py5OH=pyridine-2,6-diylbis[di(pyridin-2-yl)methanol]) that can catalyse water oxidation to produce O2 in RuIII-induced (at pH 8, highest turnover number (TON)=26.5; turnover frequency (TOF)=2.2 s-1), CeIV-induced(at pH 1.5 highest TON=16; TOF=0.75 s-1) and photo-induced(at pH 8, highest TON=43.5; TOF=0.6 s-1) reactions. A chloride ligand in one of the iron complexes is shown to affect the activity strongly, improve stability and, thereby, the performance at pH 8 but it inhibits oxygen evolution at pH 1.5. The observations are consistent with a change in mechanism for catalytic water oxidation with the Fe(Py5OH) complexes between acidic (CeIV) and near-neutral pH (RuIII).

  • 12. Dau, H.
    et al.
    Fujita, E.
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Artificial Photosynthesis: Beyond Mimicking Nature2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 22, s. 4228-4235Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this Editorial, Guest Editors Holger Dau, Etsuko Fujita, and Licheng Sun introduce the Special Issue of ChemSusChem on “Artificial Photosynthesis for Sustainable Fuels”. They discuss the need for non-fossil based fuels, introduce both biological and artificial photosynthesis, and outline various important concepts in artificial photosynthesis, including molecular and solid-state catalysts for water oxidation and hydrogen evolution, catalytic CO2 reduction, and photoelectrochemical systems.

  • 13. Ding, Xin
    et al.
    Gao, Yan
    Ye, Lu
    Zhang, Linlin
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Assembling Supramolecular Dye-Sensitized Photoelectrochemical Cells for Water Splitting2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 23, s. 3992-3995Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The method used to assemble dye-sensitized photoelectrochemical (DS-PEC) devices plays a vital role in determining its photoactivity and stability. We report a simple and effective method to assemble supramolecular DS-PECs introducing PMMA as support material and a catalyst modified with long carbon chains as photoanodes. The long carbon chains in combination with PMMA allow to better immobilize the catalyst. DS-PECs obtained by this simple method have display excellent photoactivities and stabilities. A photocurrent density of 1.1mAcm(-2) and a maximum IPCE of 9.5% have been obtained with a 0.2V vs NHE external bias.

  • 14.
    Doubaji, Siham
    et al.
    Univ Cadi Ayyad, FST Marrakesh, LCME, Marrakech 40000, Morocco..
    Philippe, Bertrand
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Saadoune, Ismael
    Univ Cadi Ayyad, FST Marrakesh, LCME, Marrakech 40000, Morocco.;Univ Mohammed VI Polytech, Ctr Adv Mat, Ben Guerir, Morocco..
    Gorgoi, Mihaela
    Helmholtz Zentrum Berlin Mat & Energie, D-12489 Berlin, Germany..
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Solhy, Abderrahim
    Univ Mohammed VI Polytech, Ctr Adv Mat, Ben Guerir, Morocco..
    Valvo, Mario
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Rensmo, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Passivation Layer and Cathodic Redox Reactions in Sodium-Ion Batteries Probed by HAXPES2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 1, s. 97-108Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cathode material P2-NaxCo2/3Mn2/9Ni1/9O2, which could be used in Na-ion batteries, was investigated through synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES). Nondestructive analysis was made through the electrode/electrolyte interface of the first electrochemical cycle to ensure access to information not only on the active material, but also on the passivation layer formed at the electrode surface and referred to as the solid permeable interface (SPI). This investigation clearly shows the role of the SPI and the complexity of the redox reactions. Cobalt, nickel, and manganese are all electrochemically active upon cycling between 4.5 and 2.0V; all are in the 4+ state at the end of charging. Reduction to Co3+, Ni3+, and Mn3+ occurs upon discharging and, at low potential, there is partial reversible reduction to Co2+ and Ni2+. A thin layer of Na2CO3 and NaF covers the pristine electrode and reversible dissolution/reformation of these compounds is observed during the first cycle. The salt degradation products in the SPI show a dependence on potential. Phosphates mainly form at the end of the charging cycle (4.5V), whereas fluorophosphates are produced at the end of discharging (2.0V).

  • 15. Fan, Ke
    et al.
    Li, Fusheng
    Wang, Lei
    Daniel, Quentin
    Chen, Hong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Gabrielsson, Erik
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Sun, Licheng
    Immobilization of a Molecular Ruthenium Catalyst on Hematite Nanorod Arrays for Water Oxidation with Stable Photocurrent2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 19, s. 3242-3247Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photoelectrochemical (PEC) cells for light-driven water splitting are prepared using hematite nanorod arrays on conductive glass as the photoanode. These devices improve the photocurrent of the hematite-based photoanode for water splitting, owing to fewer surface traps and decreased electron recombination resulting from the one-dimensional structure. By employing a molecular ruthenium co-catalyst, which contains a strong 2,6-pyridine-dicarboxylic acid anchoring group at the hematite photoanode, the photocurrent of the PEC cell is enhanced with high stability for over 10000s in a 1m KOH solution. This approach can pave a route for combining one-dimensional nanomaterials and molecular catalysts to split water with high efficiency and stability.

  • 16.
    Fan, Ke
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Li, Fusheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Wang, Lei
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Quentin, Daniel
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Chen, H.
    Gabrielsson, Erik
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Sun, J.
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Immobilization of a Molecular Ruthenium Catalyst on Hematite Nanorod Arrays for Water Oxidation with Stable Photocurrent2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 19, s. 3242-3247Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photoelectrochemical (PEC) cells for light-driven water splitting are prepared using hematite nanorod arrays on conductive glass as the photoanode. These devices improve the photocurrent of the hematite-based photoanode for water splitting, owing to fewer surface traps and decreased electron recombination resulting from the one-dimensional structure. By employing a molecular ruthenium co-catalyst, which contains a strong 2,6-pyridine-dicarboxylic acid anchoring group at the hematite photoanode, the photocurrent of the PEC cell is enhanced with high stability for over 10000s in a 1M KOH solution. This approach can pave a route for combining one-dimensional nanomaterials and molecular catalysts to split water with high efficiency and stability.

  • 17.
    Ferdowsi, Parnian
    et al.
    Univ Guilan, Fac Engn, Dept Text Engn, Rasht 416353756, Iran.;Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Saygili, Yasemin
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Zhang, Weiwei
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Edvinsson, Tomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kavan, Ladislav
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland.;J Heyrovsky Inst Phys Chem, Prague 1823, Czech Republic..
    Mokhtari, Javad
    Univ Guilan, Fac Engn, Dept Text Engn, Rasht 416353756, Iran..
    Zakeeruddin, Shaik M.
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Grätzel, Michael
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photon & Interfaces, Dept Chem, CH-1015 Lausanne, Switzerland..
    Hagfeldt, Anders
    Ecole Polytech Fed Lausanne, Inst Chem Sci Engn, Lab Photomol Sci, Dept Chem, CH-1015 Lausanne, Switzerland..
    Molecular Design of Efficient Organic D-A-pi-A Dye Featuring Triphenylamine as Donor Fragment for Application in Dye-Sensitized Solar Cells2018Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, nr 2, s. 494-502Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A metal-free organic sensitizer, suitable for the application in dye-sensitized solar cells (DSSCs), has been designed, synthesized and characterized both experimentally and theoretically. The structure of the novel donor-acceptor--bridge-acceptor (D-A-pi-A) dye incorporates a triphenylamine (TPA) segment and 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid (BTEBA). The triphenylamine unit is widely used as an electron donor for photosensitizers, owing to its nonplanar molecular configuration and excellent electron-donating capability, whereas 4-(benzo[c][1,2,5]thiadiazol-4-ylethynyl)benzoic acid is used as an electron acceptor unit. The influences of I-3(-)/I-, [Co(bpy)(3)](3+/2+) and [Cu(tmby)(2)](2+/+) (tmby=4,4,6,6-tetramethyl-2,2-bipyridine) as redox electrolytes on the DSSC device performance were also investigated. The maximal monochromatic incident photon-to-current conversion efficiency (IPCE) reached 81% and the solar light to electrical energy conversion efficiency of devices with [Cu(tmby)(2)](2+/+) reached 7.15%. The devices with [Co(bpy)(3)](3+/2+) and I-3(-)/I- electrolytes gave efficiencies of 5.22% and 6.14%, respectively. The lowest device performance with a [Co(bpy)(3)](3+/2+)-based electrolyte is attributed to increased charge recombination.

  • 18.
    Galkin, Maxim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Samec, Joseph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Syntetisk organisk kemi.
    Selective Route to 2-Propenyl Aryls Directly from Wood by a Tandem Organosolv and Palladium-Catalysed Transfer Hydrogenolysis2014Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, nr 8, s. 2154-2158Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A tandem organosolv pulping and Pd-catalysed transfer hydrogenolysis depolymerisation and deoxygenation has been developed. The tandem process generated 2-methoxy-4-(prop-1-enyl)phenol in 23 % yield (92 % theoretical monomer yield) starting from pine wood and 2,6-dimethoxy-4-(prop-1-enyl)phenol in 49 % yield (92 % theoretical monomer yield) starting from birch wood. Only endogenous hydrogen from wood was consumed, and the reaction was performed using green solvents.

  • 19.
    Galkin, Maxim V.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Dahlstrand, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Samec, Joseph S. M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Mild and Robust Redox-Neutral Pd/C-Catalyzed Lignol -O-4 Bond Cleavage Through a Low-Energy-Barrier Pathway2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 13, s. 2187-2192Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A Pd/C catalyzed redox neutral CO bond cleavage of 2-aryloxy-1-arylethanols has been developed. The reactions are carried out at 80 degrees C, in air, using a green solvent system to yield the aryl ketones in near quantitative yields. Addition of catalytic amounts of a hydrogen source to the reaction mixture activates the catalyst to proceed through a low energy barrier pathway. Initial studies support a transfer hydrogenolysis reaction mechanism that proceeds through an initial dehydrogenation followed by an enol adsorption to Pd/C and a reductive CO bond cleavage.

  • 20.
    Galkin, Maxim V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Samec, Joseph S. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lignin Valorization through Catalytic Lignocellulose Fractionation: A Fundamental Platform for the Future Biorefinery2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 13, s. 1544-1558Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Current processes for the fractionation of lignocellulosic biomass focus on the production of high-quality cellulosic fibers for paper, board, and viscose production. The other fractions that constitute a major part of lignocellulose are treated as waste or used for energy production. The transformation of lignocellulose beyond paper pulp to a commodity (e.g., fine chemicals, polymer precursors, and fuels) is the only feasible alternative to current refining of fossil fuels as a carbon feedstock. Inspired by this challenge, scientists and engineers have developed a plethora of methods for the valorization of biomass. However, most studies have focused on using one single purified component from lignocellulose that is not currently generated by the existing biomass fractionation processes. A lot of effort has been made to develop efficient methods for lignin depolymerization. The step to take this fundamental research to industrial applications is still a major challenge. This review covers an alternative approach, in which the lignin valorization is performed in concert with the pulping process. This enables the fractionation of all components of the lignocellulosic biomass into valorizable streams. Lignocellulose fractions obtained this way (e.g., lignin oil and glucose) can be utilized in a number of existing procedures. The review covers historic, current, and future perspectives, with respect to catalytic lignocellulose fractionation processes.

  • 21.
    Galkin, Maxim V.
    et al.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Smit, Arjan T.
    Energy Res Ctr Netherlands ECN, Biomass & Energy Efficiency, Westerduinweg 3, NL-1755 LE Petten, Netherlands..
    Subbotina, Elena
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Artemenko, Konstantin A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Bergquist, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Huijgen, Wouter J. J.
    Energy Res Ctr Netherlands ECN, Biomass & Energy Efficiency, Westerduinweg 3, NL-1755 LE Petten, Netherlands..
    Samec, Joseph S. M.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Hydrogen-free catalytic fractionation of woody biomass2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 23, s. 3280-3287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The pulping industry could become a biorefinery if the lignin and hemicellulose components of the lignocellulose are valorized. Conversion of lignin into well-defined aromatic chemicals is still a major challenge. Lignin depolymerization reactions often occur in parallel with irreversible condensation reactions of the formed fragments. Here, we describe a strategy that markedly suppresses the undesired condensation pathways and allows to selectively transform lignin into a few aromatic compounds. Notably, applying this strategy to woody biomass at organosolv pulping conditions, the hemicellulose, cellulose, and lignin were separated and in parallel the lignin was transformed into aromatic monomers. In addition, we were able to utilize a part of the lignocellulose as an internal source of hydrogen for the reductive lignin transformations. We hope that the presented methodology will inspire researchers in the field of lignin valorization as well as pulp producers to develop more efficient biomass fractionation processes in the future.

  • 22.
    Galkin, Maxim V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Smit, Arjan T.
    Subbotina, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Artemenko, Konstantin A.
    Bergquist, Jonas
    Huijgen, Wouter J. J.
    Samec, Joseph S. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hydrogen-free catalytic fractionation of woody biomass2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 23, s. 3280-3287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The pulping industry could become a biorefinery if the lignin and hemicellulose components of the lignocellulose are valorized. Conversion of lignin into well-defined aromatic chemicals is still a major challenge. Lignin depolymerization reactions often occur in parallel with irreversible condensation reactions of the formed fragments. Here, we describe a strategy that markedly suppresses the undesired condensation pathways and allows to selectively transform lignin into a few aromatic compounds. Notably, applying this strategy to woody biomass at organosolv pulping conditions, the hemicellulose, cellulose, and lignin were separated and in parallel the lignin was transformed into aromatic monomers. In addition, we were able to utilize a part of the lignocellulose as an internal source of hydrogen for the reductive lignin transformations. We hope that the presented methodology will inspire researchers in the field of lignin valorization as well as pulp producers to develop more efficient biomass fractionation processes in the future.

  • 23.
    Hao, Wenming
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Björkman, Eva
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Yun, Yifeng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Lilliestråle, Malte
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Iron Oxide Nanoparticles Embedded in Activated Carbons Prepared from Hydrothermally Treated Waste Biomass2014Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, nr 3, s. 875-882Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Particles of iron oxide (Fe3O4; 20-40nm) were embedded within activated carbons during the activation of hydrothermally carbonized (HTC) biomasses in a flow of CO2. Four different HTC biomass samples (horse manure, grass cuttings, beer production waste, and biosludge) were used as precursors for the activated carbons. Nanoparticles of iron oxide formed from iron catalyst included in the HTC biomasses. After systematic optimization, the activated carbons had specific surface areas of about 800m(2)g(-1). The pore size distributions of the activated carbons depended strongly on the degree of carbonization of the precursors. Activated carbons prepared from highly carbonized precursors had mainly micropores, whereas those prepared from less carbonized precursors contained mainly mesopores. Given the strong magnetism of the activated carbon-nano-Fe3O4 composites, they could be particularly useful for water purification.

  • 24. Hao, Yan
    et al.
    Yang, Xichuan
    Zhou, Meizhen
    Cong, Jiayan
    Wang, Xiuna
    Hagfeldt, Anders
    KTH, Skolan för kemivetenskap (CHE), Kemi, Fysikalisk kemi (stängd 20110630). KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    Sun, Licheng
    Molecular Design to Improve the Performance of Donor-p Acceptor Near-IR Organic Dye-Sensitized Solar Cells2011Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 4, nr 11, s. 1601-1605Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Near-dye experience: Long, flexible carbon chains in the lateral anchoring groups of the donor part of a donor-π acceptor organic dye increase the power conversion efficiency dramatically. This performance enhancement can be ascribed to the prevention of the formation of molecular aggregates on the semiconductor nanoparticles, resulting in a lower recombination rate between transported electrons and I3- ions. A cell based on the new dye, HY113, gives a maximum IPCE value of 93% at 660nm.

  • 25. Jiang, X.
    et al.
    Yu, Z.
    Lai, J.
    Zhang, Y.
    Hu, M.
    Lei, N.
    Wang, D.
    Yang, X.
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Interfacial Engineering of Perovskite Solar Cells by Employing a Hydrophobic Copper Phthalocyanine Derivative as Hole-Transporting Material with Improved Performance and Stability2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 8, s. 1838-1845Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In high-performance perovskite solar cells (PSCs), hole-transporting materials (HTMs) play an important role in extracting and transporting the photo-generated holes from the perovskite absorber to the cathode, thus reducing unwanted recombination losses and enhancing the photovoltaic performance. Herein, solution-processable tetra-4-(bis(4-tert-butylphenyl)amino)phenoxy-substituted copper phthalocyanine (CuPc-OTPAtBu) was synthesized and explored as a HTM in PSCs. The optical, electrochemical, and thermal properties were fully characterized for this organic metal complex. The photovoltaic performance of PSCs employing this CuPc derivative as a HTM was further investigated, in combination with a mixed-ion perovskite as a light absorber and a low-cost vacuum-free carbon as cathode. The optimized devices [doped with 6 % (w/w) tetrafluoro-tetracyano-quinodimethane (F4TCNQ)] showed a decent power conversion efficiency of 15.0 %, with an open-circuit voltage of 1.01 V, a short-circuit current density of 21.9 mA cm−2, and a fill factor of 0.68. Notably, the PSC devices studied also exhibited excellent long-term durability under ambient condition for 720 h, mainly owing to the introduction of the hydrophobic HTM interlayer, which prevents moisture penetration into the perovskite film. The present work emphasizes that solution-processable CuPc holds a great promise as a class of alternative HTMs that can be further explored for efficient and stable PSCs in the future.

  • 26.
    Karlsson, Christoffer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Nicholas, James
    Univ South Australia, Future Ind Inst, Thin Film Coatings Grp, Adelaide, SA 5001, Australia.; Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England.
    Evans, Drew
    Univ South Australia, Future Ind Inst, Thin Film Coatings Grp, Adelaide, SA 5001, Australia.
    Forsyth, Maria
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Sjödin, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Howlett, Patrick C
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Pozo-Gonzalo, Cristina
    Deakin Univ, ARC Ctr Excellence Electromat Sci, Burwood 3125, Australia.
    Stable Deep Doping of Vapor-Phase Polymerized Poly(3,4-ethylenedioxythiophene)/Ionic Liquid Supercapacitors.2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 16, s. 2112-2121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Liquid-solution polymerization and vapor-phase polymerization (VPP) have been used to manufacture a series of chloride- and tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT) carbon paper electrodes. The electrochemistry, specific capacitance, and specific charge were determined for single electrodes in 1-ethyl-3-methylimidazolium dicyanamide (emim dca) ionic liquid electrolyte. VPP-PEDOT exhibits outstanding properties with a specific capacitance higher than 300 F g(-1) , the highest value reported for a PEDOT-based conducting polymer, and doping levels as high as 0.7 charges per monomer were achieved. Furthermore, symmetric PEDOT supercapacitor cells with the emim dca electrolyte exhibited a high specific capacitance (76.4 F g(-1) ) and high specific energy (19.8 Wh kg(-1) ). A Ragone plot shows that the VPP-PEDOT cells combine the high specific power of conventional ("pure") capacitors with the high specific energy of batteries, a highly sought-after target for energy storage.

  • 27. Kravchenko, Ekaterina
    et al.
    Zakharchuk, Kiryl
    Viskup, Alexander
    Grins, Jekabs
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Svensson, Gunnar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Pankov, Vladimir
    Yaremchenko, Aleksey
    Impact of Oxygen Deficiency on the Electrochemical Performance of K2NiF4-Type (La1-xSrx)(2)NiO4-delta Oxygen Electrodes2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 3, s. 600-611Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Perovskite-related (La1-xSrx)(2)NiO4-delta (x= 0.5-0.8) phases were explored for possible use as oxygen electrodes in solid electrolyte cells with a main focus on the effect of oxygen deficiency on the electrocatalytic activity. (La1-xSrx)(2)NiO4-d solid solutions were demonstrated to preserve the K2NiF4-type tetragonal structure under oxidizing conditions. Acceptor-type substitution by Sr is compensated by the formation of oxygen vacancies and electron holes and progressively increases high-temperature oxygen nonstoichiometry, which reaches as high as d= 0.40 for x= 0.8 at 950 degrees C in air. The electrical conductivity of (La1-xSrx)(2)NiO4-d ceramics at 500-1000 degrees C and p(O-2) >= 10(-3) atm is p-type metallic-like. The highest conductivity, 300 Scm(-1) at 800 degrees C in air, is observed for x= 0.6. The average thermal expansion coefficients, (14.0-15.4) x 10(-6) K-1 at 25900 degrees C in air, are sufficiently low to ensure the thermomechanical compatibility with common solid electrolytes. The polarization resistance of porous (La1-xSrx)(2)NiO4-d electrodes applied on a Ce0.9Gd0.1O2-delta solid electrolyte decreases with increasing Sr concentration in correlation with the concentration of oxygen vacancies in the nickelate lattice and the anticipated level of mixed ionic-electronic conduction. However, this is accompanied by increasing reactivity between the cell components and necessitates the microstructural optimization of the electrode materials to reduce the electrode fabrication temperature.

  • 28.
    Kwong, Wai Ling
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Kemiskt Biologiskt Centrum (KBC) ; Department of Chemistry-Ångström Laboratory Molecular Biomimetics, Uppsala University.
    Gracia-Espino, Eduardo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Lee, Cheng Choo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysiologisk botanik.
    Sandström, Robin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Wågberg, Thomas
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Messinger, Johannes
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Kemiskt Biologiskt Centrum (KBC) ; Department of Chemistry-Ångström Laboratory Molecular Biomimetics, Uppsala University.
    Cationic Vacancy Defects in Iron Phosphide: A Promising Route toward Efficient and Stable Hydrogen Evolution by Electrochemical Water Splitting2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 22, s. 4544-4551Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Engineering the electronic properties of transition metal phosphides has shown great effectiveness in improving their intrinsic catalytic activity for the hydrogen evolution reaction (HER) in water splitting applications. Herein, we report for the first time, the creation of Fe vacancies as an approach to modulate the electronic structure of iron phosphide (FeP). The Fe vacancies were produced by chemical leaching of Mg that was introduced into FeP as "sacrificial dopant". The obtained Fe-vacancy-rich FeP nanoparticulate films, which were deposited on Ti foil, show excellent HER activity compared to pristine FeP and Mg-doped FeP, achieving a current density of 10 mAcm(-2) at overpotentials of 108 mV in 1 m KOH and 65 mV in 0.5 m H2SO4, with a near-100% Faradaic efficiency. Our theoretical and experimental analyses reveal that the improved HER activity originates from the presence of Fe vacancies, which lead to a synergistic modulation of the structural and electronic properties that result in a near-optimal hydrogen adsorption free energy and enhanced proton trapping. The success in catalytic improvement through the introduction of cationic vacancy defects has not only demonstrated the potential of Fe-vacancy-rich FeP as highly efficient, earth abundant HER catalyst, but also opens up an exciting pathway for activating other promising catalysts for electrochemical water splitting.

  • 29.
    Kwong, Wai Ling
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik. Umeå University, Umeå, Sweden.
    Gracia-Espino, Eduardo
    Umeå University, Umeå, Sweden.
    Lee, Cheng Choo
    Umeå University, Umeå, Sweden.
    Sandström, Robin
    Umeå University, Umeå, Sweden.
    Wågberg, Thomas
    Umeå University, Umeå, Sweden.
    Messinger, Johannes
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik. Umeå University, Umeå, Sweden.
    Cationic Vacancy Defects in Iron Phosphide: A Promising Route toward Efficient and Stable Hydrogen Evolution by Electrochemical Water Splitting2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 22, s. 4544-4551Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Engineering the electronic properties of transition metal phosphides has shown great effectiveness in improving their intrinsic catalytic activity for the hydrogen evolution reaction (HER) in water splitting applications. Herein, we report for the first time, the creation of Fe vacancies as an approach to modulate the electronic structure of iron phosphide (FeP). The Fe vacancies were produced by chemical leaching of Mg that was introduced into FeP as "sacrificial dopant". The obtained Fevacancy-rich FeP nanoparticulate films, which were deposited on Ti foil, show excellent HER activity compared to pristine FeP and Mg-doped FeP, achieving a current density of 10 mA cm-2 at overpotentials of 108 mV in 1 m KOH and 65 mV in 0.5 m H2 SO4 , with a near-100 % Faradaic efficiency. Our theoretical and experimental analyses reveal that the improved HER activity originates from the presence of Fe vacancies, which lead to a synergistic modulation of the structural and electronic properties that result in a near-optimal hydrogen adsorption free energy and enhanced proton trapping. The success in catalytic improvement through the introduction of cationic vacancy defects has not only demonstrated the potential of Fe-vacancy-rich FeP as highly efficient, earth abundant HER catalyst, but also opens up an exciting pathway for activating other promising catalysts for electrochemical water splitting.

  • 30.
    Kärkäs, Markus D.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Svante Arrhenius väg 16C, SE-106 91 Stockholm, Sweden.
    Lignin Hydrogenolysis: Improving Lignin Disassembly through Formaldehyde Stabilization2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 10, s. 2111-2115Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Lignocellulosic biomass is available in large quantities and constitutes an attractive feedstock for the sustainable production of bulk and fine chemicals. Although methods have been established for the conversion of its cellulosic fractions, valorization of lignin has proven to be challenging. The difficulty in disassembling lignin originates from its heterogeneous structure and its propensity to undergo skeletal rearrangements and condensation reactions during biorefinery fractionation or biomass pretreatment processes. A strategy for hindering the generation of these resistive interunit linkages during biomass pretreatment has now been devised using formaldehyde as a stabilizing agent. The developed method when combined with Ru/C‐catalyzed hydrogenolysis allows for efficient disassembly of all three biomass fractions: (cellulose, hemicellulose, and lignin) and suggests that lignin upgrading can be integrated into prevailing biorefinery schemes.

  • 31.
    Lacey, Matthew
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Österlund, Viking
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström.
    Bergfelt, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Jeschull, Fabian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Bowden, Tim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi.
    Brandell, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    A Robust, Water-Based, Functional Binder Framework for High-Energy Lithium-Sulfur Batteries2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 13, s. 2758-2766Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report here a water-based functional binder framework for the lithium-sulfur battery systems, based on the general combination of a polyether and an amide-containing polymer. These binders are applied to positive electrodes optimised towards high-energy electrochemical performance based only on commercially available materials. Electrodes with up to 4 mAhcm(-2) capacity and 97-98% coulombic efficiency are achievable in electrodes with a 65% total sulfur content and a poly(ethylene oxide): poly(vinylpyrrolidone) (PEO: PVP) binder system. Exchange of either binder component for a different polymer with similar functionality preserves the high capacity and coulombic efficiency. The improvement in coulombic efficiency from the inclusion of the coordinating amide group was also observed in electrodes where pyrrolidone moieties were covalently grafted to the carbon black, indicating the role of this functionality in facilitating polysulfide adsorption to the electrode surface. The mechanical properties of the electrodes appear not to significantly influence sulfur utilisation or coulombic efficiency in the short term but rather determine retention of these properties over extended cycling. These results demonstrate the robustness of this very straightforward approach, as well as the considerable scope for designing binder materials with targeted properties.

  • 32.
    Lai, Qiwen
    et al.
    Univ New S Wales, Sch Chem Engn, MERLin Grp, Sydney, NSW 2052, Australia..
    Paskevicius, Mark
    Aarhus Univ, Dept Chem, DK-8000 Aarhus, Denmark.;Aarhus Univ, iNANO, DK-8000 Aarhus, Denmark.;Curtin Univ, Dept Phys Astron & Med Radiat Sci, Bentley, WA 6102, Australia..
    Sheppard, Drew A.
    Curtin Univ, Dept Phys Astron & Med Radiat Sci, Bentley, WA 6102, Australia..
    Buckley, Craig E.
    Curtin Univ, Dept Phys Astron & Med Radiat Sci, Bentley, WA 6102, Australia..
    Thornton, Aaron W.
    CSIRO, Clayton, Vic 3169, Australia..
    Hill, Matthew R.
    CSIRO, Clayton, Vic 3169, Australia..
    Gu, Qinfen
    Australian Synchrotron, Clayton, Vic 3168, Australia..
    Mao, Jianfeng
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Huang, Zhenguo
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Liu, Hua Kun
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Guo, Zaiping
    Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2500, Australia..
    Banerjee, Amitava
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Chakraborty, Sudip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Aguey-Zinsou, Kondo-Francois
    Univ New S Wales, Sch Chem Engn, MERLin Grp, Sydney, NSW 2052, Australia..
    Hydrogen Storage Materials for Mobile and Stationary Applications: Current State of the Art2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 17, s. 2789-2825Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the limitations to the widespread use of hydrogen as an energy carrier is its storage in a safe and compact form. Herein, recent developments in effective high-capacity hydrogen storage materials are reviewed, with a special emphasis on light compounds, including those based on organic porous structures, boron, nitrogen, and aluminum. These elements and their related compounds hold the promise of high, reversible, and practical hydrogen storage capacity for mobile applications, including vehicles and portable power equipment, but also for the large scale and distributed storage of energy for stationary applications. Current understanding of the fundamental principles that govern the interaction of hydrogen with these light compounds is summarized, as well as basic strategies to meet practical targets of hydrogen uptake and release. The limitation of these strategies and current understanding is also discussed and new directions proposed.

  • 33. Lang, A. W.
    et al.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    De Keersmaecker, M.
    Shen, D. E.
    Österholm, A.M.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Reynolds, J. R.
    Transparent Wood Smart Windows: Polymer Electrochromic Devices Based on Poly(3,4-Ethylenedioxythiophene):Poly(Styrene Sulfonate) Electrodes2018Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, nr 5, s. 854-863Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Transparent wood composites, with their high strength and toughness, thermal insulation, and excellent transmissivity, offer a route to replace glass for diffusely transmitting windows. Here, conjugated-polymer-based electrochromic devices (ECDs) that switch on-demand are demonstrated using transparent wood coated with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a transparent conducting electrode. These ECDs exhibit a vibrant magenta-to-clear color change that results from a remarkably colorless bleached state. Furthermore, they require low energy and power inputs of 3 mWh m−2 at 2 W m−2 to switch due to a high coloration efficiency (590 cm2 C−1) and low driving voltage (0.8 V). Each device component is processed with high-throughput methods, which highlights the opportunity to apply this approach to fabricate mechanically robust, energy-efficient smart windows on a large scale. 

  • 34. Lee, H.
    et al.
    Wu, X.
    Yang, X.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Ligand-Controlled Electrodeposition of Highly Intrinsically Active and Optically Transparent NiFeOxHy Film as a Water Oxidation Electrocatalyst2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 23, s. 4690-4694Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A highly intrinsically active and optically transparent NiFeOxHy water oxidation catalyst was prepared by electrodeposition of [Ni(C12-tpen)](ClO4)2 complex (Ni−C12). This NiFeOxHy film has a current density of 10 mA cm−2 with an overpotential (η) of only 298 mV at nanomolar concentration and the current density of 10 mA cm−2 remains constant over 22 h in 1 m KOH. The extremely high turnover frequency of 0.51 s−1 was obtained with η of 300 mV. More importantly, such outstanding activity and transparency (optical loss <0.5 %) of the NiFeOxHy film are attributed to a ligand effect of the dodecyl substituent in Ni−C12, which enables its future application in solar water splitting.

  • 35. Li, Hairong
    et al.
    Fu, Kunwu
    Boix, Pablo P.
    Wong, Lydia H.
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Graetzel, Michael
    Mhaisalkar, Subodh G.
    Grimsdale, Andrew C.
    Hole-Transporting Small Molecules Based on Thiophene Cores for High Efficiency Perovskite Solar Cells2014Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, nr 12, s. 3420-3425Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two new electron-rich molecules, 2,3,4,5-tetra[4,4'-bis(methoxyphenyl)aminophen-4 ''-yl]-thiophene (H111) and 4,4',5,5'-tetra[4,4'-bis(methoxyphenyl) aminophen-4 ''-yl]-2,2'-bithiophene (H112), which contain thiophene cores with arylamine side groups, are reported. When used as the hole-transporting material (HTM) in perovskite-based solar cell devices, power conversion efficiencies of up to 15.4% under AM 1.5G solar simulation were obtained. This is the highest efficiency achieved with HTMs not composed of 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) and its isomers. Both HTMs, especially H111, have great potential to replace expensive spiro-OMeTAD given their much simpler and less expensive syntheses.

  • 36.
    Li, Hairong
    et al.
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Koh, Teck Ming
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Hao, Yan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Zhou, Feng
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Abe, Yuichiro
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Su, Haibin
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Grimsdale, Andrew C.
    Nanyang Technol Univ, Energy Res Inst NTU ERI N, Sch Mat Sci & Engn, Singapore 637553, Singapore.
    Comparative Studies on Rigid pi Linker-Based Organic Dyes: Structure-Property Relationships and Photovoltaic Performance2014Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, nr 12, s. 3396-3406Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of six structurally correlated donor-pi bridge-acceptor organic dyes were designed, synthesized, and applied as sensitizers in dye-sensitized solar cells. Using the most widely studied donor (triarylamine) and cyclopenta[1,2-b:5,4-b’]dithiophene or cyclopenta[1,2-b: 5,4-b’] dithiophene[2’,1’:4,5]thieno[2,3-d] thiophene as pi spacers, their structure-property relationships were investigated in depth by photophysical techniques and theoretical calculations. It was found that the photovoltaic performance of these dyes largely depends on their electronic structures, which requires synergistic interaction between donors and acceptors. Increasing the electron richness of the donor or the elongation of pi-conjugated bridges does not necessarily lead to higher performance. Rather, it is essential to rationally design the dyes by balancing their light-harvesting capability with achieving suitable energy levels to guarantee unimpeded charge separation and transport.

  • 37. Li, Ling
    et al.
    Hao, Yan
    Yang, Xichuan
    Zhao, Jianzhang
    Tian, Haining
    Teng, Chao
    Hagfeldt, Anders
    Sun, Licheng.
    A Double-Band Tandem Organic Dye-sensitized Solar Cell with an Efficiency of 11.5 %.2011Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 4, nr 5, s. 609-612Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The absorption spectra of most org. dyes reported thus far used for mesoporous nanostructured dye-sensitized solar cells mainly cover the visible-light region. This has motivated research towards the development of new types of org. dyes(7-10) with absorption spectra extended to the near-IR and IR region. By adjusting the donor, linker, and acceptor units, this group developed a tandem Dye-sensitized Solar Cell in which the front subcell employs a ZrO2-doped nanostructured TiO2 semiconductor to improve the photovoltage and an org. 3-[2-(N,N-diphenylamino)-ethenyl]-phenoxazinyl-cyanoacrylic acid dye (TH305) to harvest sunlight in the 400-750 nm region, giving an efficiency of 9.05 % with a high photovoltage (794 mV), while the back subcell employs a normal TiO2 electrode sensitized with a different org. dye (HY103) to capture sunlight in the 500-800 nm region, achieving an addnl. efficiency of 2.45 %. The two sub-cells are sepd. by a double-sided fluoride-doped tin oxide conducting glass. Shifting the CB band of TiO2towards more neg. values is an effective way to improve the open-circuit photovoltage (Voc) and increase the DSC's efficiency. The two methods used to make the CB more neg. are : (a) adding an org. base, 4-tert-butylpyridine, to the electrolyte, and (b) doping the TiO2 with semiconductor materials with a more-neg. CB energy level (EcB), ZrO2, which has a wider band gap (ca. 5.0 eV) and a more-neg. CB level (-1.0 V vs. normal hydrogen electrode). The org. dye TH305 was chosen for the front subcell because its more neg. LUMO level (-1.28V vs. NHE) matches the ECB of ZrO2-doped TiO2. Undoped titania was used for the second sub-cell. The total conversion efficiency was 9.05%, with a Voc of 0.794V, and a Jsc of 15/20 mA/cm2. [on SciFinder(R)]

  • 38. Li, Ying-Ying
    et al.
    Gimbert, Carolina
    Llobet, Antoni
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Quantum Chemical Study of the Mechanism of Water Oxidation Catalyzed by a Heterotrinuclear Ru2Mn Complex2019Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, nr 5, s. 1101-1110Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The heterotrinuclear complex A {[Ru-II(H2O)(tpy)](2)(mu-[Mn-II(H2O)(2)(bpp)(2)])}(4+) [tpy=2,2 ':6 ',2 ''-terpyridine, bpp=3,5-bis(2-pyridyl)pyrazolate] was found to catalyze water oxidation both electrochemically and photochemically with [Ru(bpy)(3)](3+) (bpy=2,2 '-bipyridine) as the photosensitizer and Na2S2O8 as the electron acceptor in neutral phosphate buffer. The mechanism of water oxidation catalyzed by this unprecedented trinuclear complex was studied by density functional calculations. The calculations showed that a series of oxidation and deprotonation events take place from A, leading to the formation of complex 1 (formal oxidation state of Ru1(IV)Mn(III)Ru2(III)), which is the starting species for the catalytic cycle. Three sequential oxidations of 1 result in the generation of the catalytically competing species 4 (formal oxidation state of Ru1(IV)Mn(V)Ru2(IV)), which triggers the O-O bond formation. The direct coupling of two adjacent oxo ligands bound to Ru and Mn leads to the production of a superoxide intermediate Int1. This step was calculated to have a barrier of 7.2 kcal mol(-1) at the B3LYP*-D3 level. Subsequent O-2 release from Int1 turns out to be quite facile. Other possible pathways were found to be much less favorable, including water nucleophilic attack, the coupling of an oxo and a hydroxide, and the direct coupling pathway at a lower oxidation state ((RuMnRuIV)-Mn-IV-Ru-IV).

  • 39. Li, Ying-Ying
    et al.
    Ye, Ke
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Mechanism of Water Oxidation Catalyzed by a Mononuclear Manganese Complex2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 5, s. 903-911Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The design and synthesis of biomimetic Mn complexes to catalyze oxygen evolution is a very appealing goal because water oxidation in nature employs a Mn complex. Recently, the mononuclear Mn complex [LMnII(H2O)(2)](2+) [1, L=Py2N(tBu)(2), Py= pyridyl] was reported to catalyze water oxidation electro-chemically at an applied potential of 1.23 V at pH 12.2 in aqueous solution. Density functional calculations were performed to elucidate the mechanism of water oxidation promoted by this catalyst. The calculations showed that 1 can lose two protons and one electron readily to produce [LMnIII(OH)(2)](+) (2), which then undergoes two sequential proton-coupled electron-transfer processes to afford [(LMnOO)-O-V](+) (4). The O-O bond formation can occur through direct coupling of the two oxido ligands or through nucleophilic attack of water. These two mechanisms have similar barriers of approximately 17 kcal mol(-1). The further oxidation of 4 to generate [(LMnO)-O-VI-O](2+) (5), which enables O-O bond formation, has a much higher barrier. In addition, ligand degradation by C-H activation has a similar barrier to that for the O-O bond formation, and this explains the relatively low turnover number of this catalyst.

  • 40.
    Li, Yuanyuan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Fu, Qiliang
    Rojas, Ramiro
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Yan, Min
    KTH, Skolan för elektro- och systemteknik (EES).
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellens Centrum BiMaC Innovation. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Lignin-Retaining Transparent Wood2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 17, s. 3445-3451Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80wt% of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83%, haze of 75%, thermal conductivity of 0.23WmK(-1), and work-tofracture of 1.2MJm(-3) (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings.

  • 41. Liao, Rong-Zhen
    et al.
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Quantum Chemical Modeling of Homogeneous Water Oxidation Catalysis2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 22, s. 4236-4263Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The design of efficient and robust water oxidation catalysts has proven challenging in the development of artificial photosynthetic systems for solar energy harnessing and storage. Tremendous progress has been made in the development of homogeneous transition-metal complexes capable of mediating water oxidation. To improve the efficiency of the catalyst and to design new catalysts, a detailed mechanistic understanding is necessary. Quantum chemical modeling calculations have been successfully used to complement the experimental techniques to suggest a catalytic mechanism and identify all stationary points, including transition states for both O-O bond formation and O-2 release. In this review, recent progress in the applications of quantum chemical methods for the modeling of homogeneous water oxidation catalysis, covering various transition metals, including manganese, iron, cobalt, nickel, copper, ruthenium, and iridium, is discussed.

  • 42.
    Lindahl, Niklas
    et al.
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Eriksson, Björn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Groenbeck, Henrik
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Wreland Lindström, Rakel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Wickman, Bjoern
    Chalmers Univ Technol, Dept Phys, SE-41296 Gothenburg, Sweden..
    Fuel Cell Measurements with Cathode Catalysts of Sputtered Pt3Y Thin Films2018Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 11, nr 9, s. 1438-1445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fuel cells are foreseen to have an important role in sustainable energy systems, provided that catalysts with higher activity and stability are developed. In this study, highly active sputtered thin films of platinum alloyed with yttrium (Pt3Y) are deposited on commercial gas diffusion layers and their performance in a proton exchange membrane fuel cell is measured. After acid pretreatment, the alloy is found to have up to 2.5 times higher specific activity than pure platinum. The performance of Pt3Y is much higher than that of pure Pt, even if all of the alloying element was leached out from parts of the thin metal film on the porous support. This indicates that an even higher performance is expected if the structure of the Pt3Y catalyst or the support could be further improved. The results show that platinum alloyed with rare earth metals can be used as highly active cathode catalyst materials, and significantly reduce the amount of platinum needed, in real fuel cells.

  • 43.
    Liu, Chenjuan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Brant, William
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Younesi, Reza
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Dong, Yanyan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi. Beijing Forestry Univ, Coll Mat Sci & Technol, Beijing Key Lab Lignocellulos Chem, Beijing 100083, Peoples R China..
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Zhu, Jiefang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi. Dalian Univ Technol, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Towards an Understanding of Li2O2 Evolution in Li-O2 Batteries: An In-operando Synchrotron X-ray Diffraction Study2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 7, s. 1592-1599Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the major challenges in developing high-performance Li-O-2 batteries is to understand the Li2O2 formation and decomposition during battery cycling. In this study, this issue was investigated by synchrotron radiation powder X-ray diffraction. The evolution of Li2O2 morphology and structure was observed under actual electrochemical conditions of battery operation. By quantitatively tracking Li2O2 during discharge and charge, a two-step process was suggested for both growth and oxidation of Li2O2 owing to different mechanisms during two stages of both oxygen reduction reaction and oxygen evolution reaction. From an observation of the anisotropic broadening of Li2O2 in XRD patterns, it was inferred that disc-like Li2O2 grains are formed rapidly in the first step of discharge. These grains can stack together so that they facilitate the nucleation and growth of toroidal Li2O2 particles with a LiO2-like surface, which could cause parasitic reactions and hinder the formation of Li2O2. During the charge process, Li2O2 is firstly oxidized from the surface, followed by a delithiation process with a faster oxidation of the bulk by stripping the interlayer Li atoms to form an off-stoichiometric intermediate. This fundamental insight brings new information on the working mechanism of Li-O-2 batteries.

  • 44.
    Liu, Jia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Renault, Steven
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Brandell, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Zhu, Jiefang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    An Organic Catalyst for Li-O-2 Batteries: Dilithium Quinone-1,4-Dicarboxylate2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 13, s. 2198-2203Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solid organic electrocatalysts have hardly been tested in Li-O-2 batteries. Here, a new solid organic electrocatalyst, dilithium quinone-1,4-dicarboxylate (Li2C8H2O6) is presented, which is expected to overcome the shortcomings of inorganic catalysts. The function-oriented synthesis is low cost and low polluting. The electrocatalytic performance is evaluated by following the degradation of Li2O2 during the charge process in a Li-O-2 cell through insitu XRD and operando synchrotron radiation powder XRD (SR-PXD) measurements. The results indicate that the electrocatalytic activity of Li2C8H2O6 is similar to that of commercial Pt. The Li2O2 decomposition in a cell with Li2C8H2O6 catalyst follows a pseudo-zero-order reaction, virtually without any side reactions. These results provide an insight into the development of new organic catalysts for the oxygen evolution reaction (OER) in Li-O-2 batteries.

  • 45.
    Lofstedt, Joakim
    et al.
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Dahlstrand, Christian
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Orebom, Alexander
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Meuzelaar, Gerrit
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Sawadjoon, Supaporn
    Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Galkin, Maxim V.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Agback, Peter
    Swedish Univ Agr Sci, Dept Chem, Uppsala BioCtr, POB 7015, S-75007 Uppsala, Sweden..
    Wimby, Martin
    Valmet AB, Regnbagsgatan 6, S-41755 Gothenburg, Sweden..
    Corresa, Elena
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Mathieu, Yannick
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Sauvanaud, Laurent
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Eriksson, Sören
    Preem AB, Warfvinges Vag 45, S-11251 Stockholm, Sweden..
    Corma, Avelino
    Univ Politecn Valencia, Inst Tecnol Quim UPV CSIC, Ave Tarongers S-N, E-46022 Valencia, Spain..
    Samec, Joseph S. M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC. Renfuel AB, Sturegatan 38, S-11436 Stockholm, Sweden..
    Green Diesel from Kraft Lignin in Three Steps2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 12, s. 1392-1396Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Precipitated kraft lignin from black liquor was converted into green diesel in three steps. A mild Ni-catalyzed transfer hydrogenation/hydrogenolysis using 2-propanol generated a lignin residue in which the ethers, carbonyls, and olefins were reduced. An organocatalyzed esterification of the lignin residue with an insitu prepared tall oil fatty acid anhydride gave an esterified lignin residue that was soluble in light gas oil. The esterified lignin residue was coprocessed with light gas oil in a continous hydrotreater to produce a green diesel. This approach will enable the development of new techniques to process commercial lignin in existing oil refinery infrastructures to standardized transportation fuels in the future.

  • 46.
    Loos, Stefan
    et al.
    Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany;Fraunhofer Inst Mfg Technol & Adv Mat IFAM, Winterbergstr 28, D-01277 Dresden, Germany.
    Zaharieva, Ivelina
    Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany.
    Chernev, Petko
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik. Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany.
    Lissner, Andreas
    Tech Univ Bergakad Freiberg, Inst Phys Chem, Leipziger Str 29, D-09599 Freiberg, Germany.
    Dau, Holger
    Free Univ Berlin, Inst Expt Phys, Arnimallee 14, D-014195 Berlin, Germany.
    Electromodified NiFe Alloys as Electrocatalysts for Water Oxidation: Mechanistic Implications of Time-Resolved UV/Vis Tracking of Oxidation State Changes2019Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, nr 9, s. 1966-1976Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Facile electromodification of metallic NiFe alloys leads to a series of NiFe oxyhydroxide surface films with excellent electrocatalytic performance in alkaline water oxidation. During cyclic voltammetry and after sudden potential jumps between noncatalytic and catalytic potentials, Ni oxidation/reduction was tracked with millisecond time resolution by a UV/Vis reflectance signal. Optimal catalysis at intermediate Ni/Fe ratios is explained by two opposing trends for increasing Fe content: a)pronounced slowdown of the Ni2+/Ni3+ oxidation step and b)increased reactivity of the most oxidized catalyst state detectable at catalytic potentials. This state may involve an equilibrium between Ni4+ ions and Ni2+ ions with neighboring ligand holes, possibly in the form of bound peroxides.

  • 47. Ma, Yue
    et al.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Gustafsson, Torbjörn
    Edström, Kristina
    Recycled Poly(vinyl alcohol) Sponge for Carbon Encapsulation of Size-Tunable Tin Dioxide Nanocrystalline Composites2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 12, s. 2084-2092Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The recycling of industrial materials could reduce their environmental impact and waste haulage fees and result in sustainable manufacturing. In this work, commercial poly(vinyl alcohol) (PVA) sponges are recycled into a macroporous carbon matrix to encapsulate size-tunable SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) through a scalable, flash-combustion method. The hydroxyl groups present copiously in the recycled PVA sponges guarantee a uniform chemical coupling with a tin(IV) citrate complex through intermolecular hydrogen bonds. Then, a scalable, ultrafast combustion process (30s) carbonizes the PVA sponge into a 3D carbon matrix. This PVA-sponge-derived carbon could not only buffer the volume fluctuations upon the Li-Sn alloying and dealloying processes but also afford a mixed conductive network, that is, a continuous carbon framework for electrical transport and macropores for facile electrolyte percolation. The best-performing electrode based on this composite delivers a rate performance up to 9.72C (4Ag(-1)) and long-term cyclability (500cycles) for Li+ ion storage. Moreover, cyclic voltammograms demonstrate the coexistence of alloying and dealloying processes and non-diffusion-controlled pseudocapacitive behavior, which collectively contribute to the high-rate Li+ ion storage.

  • 48.
    Ma, Yue
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Tai, Cheuk-Wai
    Stockholm University.
    Gustafsson, Torbjörn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Edström, Kristina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Recycled Poly(vinyl alcohol) Sponge for Carbon Encapsulation of Size-Tunable Tin Dioxide Nanocrystalline Composites2015Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, nr 12, s. 2084-2092Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The recycling of industrial materials could reduce their environmental impact and waste haulage fees and result in sustainable manufacturing. In this work, commercial poly(vinyl alcohol) (PVA) sponges are recycled into a macroporous carbon matrix to encapsulate size-tunable SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) through a scalable, flash-combustion method. The hydroxyl groups present copiously in the recycled PVA sponges guarantee a uniform chemical coupling with a tin(IV) citrate complex through intermolecular hydrogen bonds. Then, a scalable, ultrafast combustion process (30s) carbonizes the PVA sponge into a 3D carbon matrix. This PVA-sponge-derived carbon could not only buffer the volume fluctuations upon the Li-Sn alloying and dealloying processes but also afford a mixed conductive network, that is, a continuous carbon framework for electrical transport and macropores for facile electrolyte percolation. The best-performing electrode based on this composite delivers a rate performance up to 9.72C (4Ag(-1)) and long-term cyclability (500cycles) for Li+ ion storage. Moreover, cyclic voltammograms demonstrate the coexistence of alloying and dealloying processes and non-diffusion-controlled pseudocapacitive behavior, which collectively contribute to the high-rate Li+ ion storage.

  • 49.
    Mahanti, Bani
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    González Miera, Greco
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm, Sweden.
    Martínez-Castro, Elisa
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm, Sweden.
    Bedin, Michele
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Martín-Matute, Belen
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholm, Sweden.
    Ott, Sascha
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Thapper, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Molekylär biomimetik.
    Homogeneous Water Oxidation by Half-Sandwich Iridium(III) N-Heterocyclic Carbene Complexes with Pendant Hydroxy and Amino Groups2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 22, s. 4616-4623Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, we report three IrIIICp* complexes with hydroxy- or amino-functionalized N-heterocyclic carbene (NHC) ligands that catalyze efficient water oxidation induced by addition of ceric ammonium nitrate (CAN). The pendant hydroxy or amino groups are very important for activity, and the complexes with heteroatom-functionalized NHC ligands show up to 15 times higher rates of oxygen evolution in CAN-induced water oxidation than a reference IrIIICp* complex without heteroatom functionalization. The formation of molecular high-valent Ir intermediates that are presumably involved in the rate-determining step for water oxidation is established by UV/Vis spectroscopy and ESI-MS under turnover conditions. The hydroxy groups on the NHC ligands, as well as chloride ligands on the iridium center are proposed to structurally stabilize the high-valent species, and thereby improve the catalytic activity. The IrIII complex with a hydroxy-functionalized NHC shows the highest catalytic activity with a TON of 2500 obtained in 3 h and with ~90 % yield relative to the amount of oxidant used.

  • 50. Mahanti, Bani
    et al.
    González Miera, Greco
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Martínez-Castro, Elisa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bedin, Michele
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ott, Sascha
    Thapper, Anders
    Homogeneous Water Oxidation by Half-Sandwich Iridium(III) N-Heterocyclic Carbene Complexes with Pendant Hydroxy and Amino Groups2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 22, s. 4616-4623Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, we report three (IrCp)-Cp-III* complexes with hydroxy-or amino-functionalized N-heterocyclic carbene (NHC) ligands that catalyze efficient water oxidation induced by addition of ceric ammonium nitrate (CAN). The pendant hydroxy or amino groups are very important for activity, and the complexes with heteroatom-functionalized NHC ligands show up to 15 times higher rates of oxygen evolution in CAN-induced water oxidation than a reference (IrCp)-Cp-III* complex without heteroatom functionalization. The formation of molecular high-valent Ir intermediates that are presumably involved in the rate-determining step for water oxidation is established by UV/Vis spectroscopy and ESI-MS under turnover conditions. The hydroxy groups on the NHC ligands, as well as chloride ligands on the iridium center are proposed to structurally stabilize the highvalent species, and thereby improve the catalytic activity. The Ir-III complex with a hydroxy-functionalized NHC shows the highest catalytic activity with a TON of 2500 obtained in 3 h and with >90% yield relative to the amount of oxidant used.

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