Multi-modal optimization of bismuth vanadate photoanodes via combinatorial alloying and hydrogen processing.

Alloying transition metals, such as Mo, into BiVO4 has emerged as the primary mechanism for improving carrier transport in this photoanode for solar fuels production. The present work establishes the generality of improving photoelectrochemical performance through co-alloying with a transition metal electron donor and a structure-modulating rare earth. Further improvement for all such alloys is obtained by annealing the oxide materials in H2, ultimately producing photoanodes with above 3 mA cm-2 photocurrent density under AM 1.5G illumination, in the top tier of compact BiVO4 films.