Simultaneous enhancement in charge separation and interfacial charge transfer of BiVO4 photoanode for photoelectrochemical water oxidation

Abstract

Bismuth vanadate (BiVO4) has been identified as one of the promising photoanode materials for photoelectrochemical (PEC) water splitting. Nevertheless, the serious charge recombination and sluggish kinetics of oxygen evolution reaction (OER) are the main factors limiting its PEC performance. In this contribution, copper incorporated nanostructured BiVO4 photoanodes (nanoCu:BiVO4) were prepared by converting the electrodeposited BiOI nanosheets in the presence of copper and vanadium sources and subsequent thermal treatment. nanoCu:BiVO4 prepared with a suitable amount of copper consists of well-interconnected BiVO4 nanoparticles coated with p-type Cu(I) vanadate. The well-interconnected structure improved the kinetics of the charge transport, whereas n–p heterojunction formed between BiVO4 and Cu(I) vanadate remarkably improved the efficiencies of charge separation and interfacial charge transfer. Further improvement in OER kinetics and photostability of nanoCu:BiVO4 was demonstrated by interfacing nanoCu:BiVO4 with nickel-iron oxyhydroxide based OER catalyst.