Stabilizing CuO photocathode with a Cu3N protection shell

CuO, as a promising photocathode material, suffers from severe photocorrosion in photoelectrochemical water splitting applications. Herein, a Cu3N protection shell was used to protect the CuO photocathode for the first time to effectively suppress the photocorrosion of CuO. Consequently, the Cu3N-protected CuO photocathode shows improved stability, retaining 80% of its initial current density in a 20-min test, while only 10% of the initial current density can be retained for the bare photocathode. This work may provide an important strategy for using Cu3N shells to stabilize unstable photocathodes.