On the Homogeneity of a Cobalt-Based Water Oxidation Catalyst

The homogeneity of molecular Co-based wateroxidation catalysts (WOCs) has been a subject of debate over thelast 10 years as assumed various homogeneous Co-based WOCswere found to actually form CoOxunder operating conditions. Thehomogeneity of the Co(HL)(HL=N,N-bis(2,2 '-bipyrid-6-yl)amine) system was investigated with cyclic voltammetry,electrochemical quartz crystal microbalance, and X-ray photo-electron spectroscopy. The obtained experimental results werecompared with heterogeneous CoOx. Although it is shown thatCo(HL) interacts with the electrode during electrocatalysis, theformation of CoOxwas not observed. Instead, a molecular depositof Co(HL) was found to be formed on the electrode surface. Thisstudy shows that deposition of catalytic material is not necessarilylinked to the decomposition of homogeneous cobalt-based water oxidation catalysts.

Automated summary

This study demonstrates through experimental results that not all molecular Co-based water oxidation catalysts necessarily form CoOx under operating conditions, and the deposition of catalytic material is not necessarily linked to the decomposition of the catalyst.