title: A Robust Molecular Catalyst Generated In Situ for Photo- and Electrochemical Water Oxidation.
abstract: Water splitting is the key step towards artificial photosystems for solar energy conversion and storage in the form of chemical bonding. The oxidation of water is the bottle-neck of this process that hampers its practical utility; hence, efficient, robust, and easy to make catalytic systems based on cheap and earth-abundant materials are of exceptional importance. Herein, an in situ generated cobalt catalyst, [CoII(TCA)2(H2O)2] (TCA=1-mesityl-1,2,3-1H-triazole-4-carboxylate), that efficiently conducts photochemical water oxidation under near-neutral conditions is presented. The catalyst showed high stability under photolytic conditions for more than 3 h of photoirradiation. During electrochemical water oxidation, the catalytic system assembled a catalyst film, which proved not to be cobalt oxide/hydroxide as normally expected, but instead, and for the first time, generated a molecular cobalt complex that incorporated the organic ligand bound to cobalt ions. The catalyst film exhibited a low overpotential for electrocatalytic water oxidation (360 mV) and high oxygen evolution peak current densities of 9 and 2.7 mA cm-2on glassy carbon and indium-doped tin oxide electrodes, respectively, at only 1.49 and 1.39 V (versus a normal hydrogen electrode), respectively, under neutral conditions. This finding, exemplified on the in situ generated cobalt complex, might be applicable to other molecular systems and suggests that the formation of a catalytic film in electrochemical water oxidation experiments is not always an indication of catalyst decomposition and the formation of nanoparticles.
authors.affiliation: State Key Laboratory of Advanced Technology for Materials, Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, P.R. China.|School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, P.R. China.|National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk, 634050, Russia.|Chemistry Department, Faculty of Science, Fayoum University, Fayoum, 36514, Egypt.
authors.forename: Hussein A
authors.initials: HA
authors.lastname: Younus
authors.affiliation: State Key Laboratory of Advanced Technology for Materials, Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, P.R. China.|School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, P.R. China.|National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk, 634050, Russia.
authors.forename: Nazir
authors.initials: N
authors.lastname: Ahmad
authors.affiliation: State Key Laboratory of Advanced Technology for Materials, Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, P.R. China.
authors.forename: Adeel H
authors.initials: AH
authors.lastname: Chughtai
authors.affiliation: Center for Molecular Modeling, Ghent University, Technology Park 903, 9052, Zwijnaarde, Belgium.|Department of Physics and Competence Center for Catalysis, Chalmers University of Technology, Fysikgränd 3, Göteborg, Sweden.
authors.forename: Matthias
authors.initials: M
authors.lastname: Vandichel
authors.affiliation: Department of Physics and Competence Center for Catalysis, Chalmers University of Technology, Fysikgränd 3, Göteborg, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Busch
authors.affiliation: Department of Inorganic and Physical Chemistry, Laboratory of Organometallic Chemistry and Catalysis, Ghent University, Krijgslaan 281 (S-3), 9000, Ghent, Belgium.
authors.forename: Kristof
authors.initials: K
authors.lastname: Van Hecke
authors.affiliation: National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk, 634050, Russia.
authors.forename: Mekhman
authors.initials: M
authors.lastname: Yusubov
authors.affiliation: School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, P.R. China.
authors.forename: Shaoxian
authors.initials: S
authors.lastname: Song
authors.affiliation: State Key Laboratory of Advanced Technology for Materials, Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, P.R. China.|School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, P.R. China.|National Research Tomsk Polytechnic University, Lenin Avenue 30, Tomsk, 634050, Russia.|Department of Inorganic and Physical Chemistry, Laboratory of Organometallic Chemistry and Catalysis, Ghent University, Krijgslaan 281 (S-3), 9000, Ghent, Belgium.
authors.forename: Francis
authors.identifier: 0000-0002-5184-5500
authors.initials: F
authors.lastname: Verpoort
mesh_terms: D002384:Catalysis; D004563:Electrochemistry; D004566:Electrodes; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water
keywords: cobalt; electrochemistry; oxidation; photochemistry; water splitting