Mo-doped BiVO4@reduced graphene oxide composite as an efficient photoanode for photoelectrochemical water splitting

Abstract

Monoclinic Bismuth vanadate (BiVO4) nanomaterial is an attractive, efficient photoanode for photoelectrochemical (PEC) water splitting due to excellent visible light activity and good photo-chemical stability. However, poor charge separation and low charge carrier mobility hinder the improvement of PEC performance of BiVO4. In this work, molybdenum (Mo)-doped BiVO4@reduced graphene oxide (rGO) nanocomposites are fabricated and their potential to serve as photoanodes for PEC water splitting is evaluated. This composite, by the introduction of Mo-dopant and rGO in BiVO4 enhances the PEC performance for water oxidation for they assist in reducing charge recombination and enhancement of photocurrent. As a result, the Mo-BiVO4@rGO composite photoanode exhibited a photocurrent density of 8.51 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE), which is two and four times greater than that of Mo-BiVO4 (5.3 mA cm-2 at 1.23 V versus RHE) and pristine BiVO4 (2.01 mA cm−2 at 1.23 V versus RHE) photoactive electrodes. In addition, good photo-conversion efficiency, low charge transfer resistance and good external quantum efficiency (EQE) are achieved for this ternary nanocomposite. These studies reveal the improved PEC activity for water splitting by the Mo-doped BiVO4@rGO, and indicated that this approach can be used to design more efficient photoanodes for PEC water splitting.