Stable and efficient solar-driven photoelectrochemical water splitting into H2 and O2 based on a BaTaO2N photoanode decorated with CoO microflowers.

Stable and efficient photoelectrochemical water splitting has been achieved using a BaTaO2N photoanode decorated with CoO microflowers. The CoO microflowers effectively collect holes from BaTaO2N which kinetically protects BaTaO2N against photocorrosion. A Faraday efficiency of almost unity (99.2%) has been recorded for O2 evolution reactions. The tips of the CoO microflowers are the most active sites for water oxidation reactions.