Copper oxide nanowires for efficient photoelectrochemical water splitting

Photoelectrochemical (PEC) splitting of water into hydrogen and oxygen by the direct use of sunlight is an ideal, renewable method for solar-to-chemical conversion. Photocathodes based on p-type copper oxide (CuO) are promising materials for large-scale and widespread PEC water splitting due to the abundance of copper element, suitable band gap, and favorable band alignments. In this work, we fabricated one-dimensional CuO nanowires on Cu foils via a facile thermal-treatment process for PEC water splitting. The well-defined CuO nanowire-based photocathodes exhibit an obvious photocurrent responsive character of a p-type semiconductor with onset potential at similar to 700 mV vs. RHE. The CuO photocathode shows a photocurrent of similar to 1.4 mA cm(-2) at 0 V vs. RHE under AM 1.5 G irradiation, which is one of the highest photocurrents based on bare CuO photocathode. Further depositing Pt nanoparticles as cocatalyst on the surface of CuO nanowires to accelerate surface reaction and inhibit charge accumulating at semiconductor/solution interface, resulting in a significant improvement of the stability for photoelectrodes. Our work reports a promising method for fabricating well-defined metal oxides-based photoelectrodes, which providing a promising candidate for highly efficient no bias PEC devices for solar fuels production.