1. Photochemical and electrocatalytic water oxidation activity of cobalt carbodiimide
- Author
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Greta R. Patzke, Menny Shalom, Debora Ressnig, Fabio Evangelisti, Jörg Patscheider, Markus Antonietti, René Moré, University of Zurich, and Ressnig, Debora
- Subjects
10120 Department of Chemistry ,Materials science ,Inorganic chemistry ,Oxide ,chemistry.chemical_element ,2105 Renewable Energy, Sustainability and the Environment ,1600 General Chemistry ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,7. Clean energy ,01 natural sciences ,law.invention ,Catalysis ,chemistry.chemical_compound ,law ,540 Chemistry ,General Materials Science ,Cobalt oxide ,Carbodiimide ,Electrolysis ,Renewable Energy, Sustainability and the Environment ,Oxygen evolution ,General Chemistry ,021001 nanoscience & nanotechnology ,2500 General Materials Science ,0104 chemical sciences ,chemistry ,Catalytic oxidation ,0210 nano-technology ,Cobalt - Abstract
Cobalt carbodiimide is introduced as a heterogeneous non-oxidic water oxidation catalyst prototype with dual photochemical and electrocatalytic activity in neutral and basic media. CoNCN exhibits higher initial turnover frequencies of (TOF/SBET: 2.1 × 10−1) for visible-light-driven oxygen evolution than cobalt oxide catalysts (TOF/SBET: 3.5 × 10−3) and a 18% higher oxygen yield (Ru-dye sensitized standard setup). Furthermore, CoNCN maintains stable current densities in electrolysis over 20 h, and structural tuning through cationic substitution revealed that mixed (Co, Ni)NCN catalysts with low Ni contents display higher current densities than pristine CoNCN. A wide range of bulk (XAFS/EXAFS, XRD, FTIR) and surface (XPS, EELS, HRTEM) analytical methods together with catalytic parameter variations and reference experiments were performed to confirm the stability of CoNCN under standard operational conditions. The carbodiimide matrix thus offers a straightforward structural alternative to oxide systems and a clear-cut starting point for optimization strategies and for mechanistic studies on the possible role of active carbon or nitrogen sites. This paves the way to metal carbodiimides as a novel catalyst design platform for heterogeneous energy conversion systems.
- Published
- 2015