Issue 9, 2015

Photochemical and electrocatalytic water oxidation activity of cobalt carbodiimide

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.

Graphical abstract: Photochemical and electrocatalytic water oxidation activity of cobalt carbodiimide

Supplementary files

Article information

Article type
Paper
Submitted
16 Jan 2015
Accepted
23 Jan 2015
First published
26 Jan 2015
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2015,3, 5072-5082

Author version available

Photochemical and electrocatalytic water oxidation activity of cobalt carbodiimide

D. Ressnig, M. Shalom, J. Patscheider, R. Moré, F. Evangelisti, M. Antonietti and G. R. Patzke, J. Mater. Chem. A, 2015, 3, 5072 DOI: 10.1039/C5TA00369E

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