Improved Surface Charge Transfer in MoO3/BiVO4 Heterojunction Film for Photoelectrochemical Water Oxidation

A MoO 3 /BiVO 4 heterojunction film consisting of dispersed nano-MoO 3 on the surface of BiVO 4 nanoflake was constructed for photoelectrochemical water oxidation . In comparison with bare BiVO 4 and MoO 3 film, the MoO 3 /BiVO 4 heterojunction film shows enhanced water oxidation activity. At 0.8   V vs. SCE, the photocurrent on the optimal MoO 3 /BiVO 4 heterojunction film increases by up to about 6 times compared to that on the bare BiVO 4 film. The conduction and valence band potential of MoO 3 are found to be more positive than those of BiVO 4 , and the electric conductivity for MoO 3 and BiVO 4 is on the order of 10 −6   S   cm −1 and 10 −9   S   cm −1 , respectively. Thus, the origin of enhanced water oxidation activity on the MoO 3 /BiVO 4 heterojunction film can be primarily ascribed to the band potential and conductivity differences between MoO 3 and BiVO 4 , which are advantageous for separating and transferring the surface charge of BiVO 4 .