An integrating photoanode consisting of BiVO4, rGO and LDH for photoelectrochemical water splitting

Abstract

The low carrier mobility of BiVO₄ is a bottleneck that limits its charge transfer in bulk or on the surface. Herein, reduced graphene oxide (rGO) nanosheets as an effective electron mediator were successfully loaded on BiVO₄ and NiFe-layered double hydroxides (NiFe-LDHs) were decorated on BiVO₄/rGO heterojunctions by two facile electrodeposition methods to construct a triadic photoanode of BiVO₄/rGO/NiFe-LDH for improvement of photoelectrochemical (PEC) water splitting efficiency of BiVO₄. This photoanode significantly extends the absorption region of visible light, increases the photocurrent density, exhibits an onset potential with a significant cathodic shift, and enhances photon-to-electron conversion efficiency (IPCE) compared with the pristine BiVO₄ photoanode. The enhancement of PEC properties benefits from the formation of p–n heterojunctions between rGO and BiVO₄ and the use of NiFe-LDH as a cocatalyst for accelerating the kinetics of oxygen evolution from water.