Facile synthesis of Bi-functional molybdenum-doped BiVO4/Molybdenum oxide heterojunction as the photocatalyst for water oxidation

Abstract

The photocatalytic ability of BiVO4 toward water oxidation is limited by the short charge diffusion path. Several strategies are proposed to increase the charge diffusion path and reduce the charge recombination of BiVO4. This work firstly applies a one-step solution method to synthesize the BiVO4 nanorod array on transparent conductive glasses and dope molybdenum in BiVO4 via incorporating the molybdenum precursor in the solution. At the same time the molybdenum oxide is found to form on the molybdenum-doped BiVO4 nanorod array surface and the preferable type II heterojunction is thus established. The smallest onset potential of 0.17 V versus reversible hydrogen electrode and the highest photocurrent density of 2.67 mA/cm2 at 1.23 V versus reversible hydrogen electrode which is five-fold of that for the BiVO4 electrode (0.04 mA/cm2) are obtained for the molybdenum-doped BiVO4/molybdenum oxide electrode with 1.2% molybdenum doping. The overwhelming photoelectrochemical performance of the molybdenum-doped BiVO4/molybdenum oxide electrode is owing to the preferable one-dimensional charge transfer path, higher carrier density, and the development of type II heterojunction. The main contribution of this work lies on the novel solution synthesis for realizing multiple efficient strategies at one time to improve the photocatalytic ability of BiVO4 toward water oxidation.