Novel synthesis of highly ordered BiVO4 nanorod array for photoelectrochemical water oxidation using a facile solution process

Abstract

Bismuth vanadate (BiVO4) with the suitable band gap and band edges is one of the efficient photocatalysts for water oxidation, but the short carrier diffusion path greatly reduces its photoelectrochemical performance. Improving intrinsic properties of BiVO4 is the basic requirement to solve serious recombination and establish efficient photocatalysts. To refine the intrinsic property of BiVO4, the morphology design is the primary strategy rarely investigated in previous works. In this study, the highly ordered cone-shape BiVO4 nanorod array is firstly fabricated on the conductive substrate via a facile solution process. Reaction time of the solution process is varied to fabricate different BiVO4 nanostructures and the possible growth mechanism of BiVO4 nanocone array is proposed. The highest photocurrent density of 1.00 mA/cm2 at 1.23 V versus reversible hydrogen electrode is obtained for the BiVO4 nanocone electrode, owing to the highest crystallinity, preferable (040) crystal plane, the smallest charge-transfer resistance and the highest carrier density. Main contribution of this study is the fundamental improvement on photocatalytic ability of BiVO4 toward water oxidation. Incorporating other materials with BiVO4 to realize heteroatom doping or heterojunction are expected to improve the photocatalytic ability of the ordered BiVO4 nanocone array and fabricate efficient photocatalysts toward water oxidation.