Fabrication of WO3 nanorod/graphene/BiV1−xMoxO4 heterojunction photoelectrode for efficient photoelectrochemical water splitting

We report the fabrication of a novel WO3 nanorod/graphene/BiV1−xMoxO4 heterojunction photoelectrode for photoelectrochemical (PEC) water splitting. The heterojunction arrays were fabricated via a hydrothermal deposition of WO3 nanorods on FTO glass, with subsequent depositing of graphene nanosheets and BiV1−xMoxO4 by spin-coating method, respectively. The structure of materials and PEC water splitting properties of the photoelectrodes were systemically investigated. The heterojunction exhibits an enhanced photocurrent density (2.27 mA/cm2 at 0.9 V vs. Ag/AgCl), which leads to a significant improvement in photoconversion efficiency (1.00% at about 0.7 V vs. Ag/AgCl). This remarkable PEC performance is mainly due to the constructive effect of the graphene (RGO) in expediting electron transfer and reducing charge recombination to realize enhanced use ratio of photo-generated carriers for the water splitting reaction. This result demonstrates the superiorities of the new graphene-mediated composites photoelectrode and provides a promising route for high-performance photoelectrochemical systems.