Photochemical and electrocatalytic water oxidation activity of cobalt carbodiimide

Debora Ressnig, Menny Shalom, Jörg Patscheider, René Moré, Fabio Evangelisti, Markus Antonietti, Greta R. Patzke

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

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.

Original languageEnglish
Pages (from-to)5072-5082
Number of pages11
JournalJournal of Materials Chemistry A
Volume3
Issue number9
DOIs
StatePublished - 7 Mar 2015
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry (all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science (all)

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