Photo-assisted water oxidation with cobalt-based catalyst formed from thin-film cobalt metal on silicon photoanodes

Integrating chemical catalysts for water splitting with photoanode materials is a longstanding challenge in demonstrating light-assisted water oxidation, a process which can be used for the generation of solar fuels. In this work we use a silicon photoanode as a substrate for processing cobalt metal films to form a cobalt-based water oxidation catalyst (Co–Pi) integrated with the silicon photoanode. The Co–Pi coated photoanodes show catalytic onset at 0.85 V under illumination, which is better than silicon photoanodes coated with ITO and solution-deposited Co–Pi (catalytic onset at 1.05 V) and significantly better photoanodes with only ITO contacts (catalytic activity onset at 1.6 V).