All First Row Transition Metal Oxide Photoanode for Water Splitting Based on Cu₃V₂O₈

Identification of viable photoanode candidates for use in a tandem photoelectrochemical water splitting system remains a significant challenge to the realization of efficient solar-driven hydrogen production. Herein, copper vanadate (Cu 3 V 2 O 8 ) is introduced as a new, all first row transition metal oxide with a band gap of near 2 eV that makes it suitable as a photoanode candidate in such a solar water splitting system. In this work, many of the key physical and photoelectrochemical properties of Cu 3 V 2 O 8 are established including band gap, doping type, ability to extrinsically dope, flat-band potential, band positions, electron diffusion length, chemical stability, and O 2 evolution faradaic efficiency. This study provides a key initial step in identifying the features that can lead to a complete understanding of this new ternary metal oxide and motivate discovery of related photoanodes comprised of multicomponent oxides.