An Aqueous-Based BiVO4 Precursor for Controlled and Enhanced Properties Towards Water Splitting

Abstract

Electrochemical deposition of Bi is often obtained from non-aqueous solutions due to its natural instability in water-based solutions. In this work, we report an easy and highly reproducible method for Bi deposition on optical conductive supports as a precursor for BiVO4 synthesis. After obtaining BiVO4 from the Bi layers through hydrothermal reaction with a vanadyl precursor, the material is further modified via potentiodynamic polarization as previously demonstrated for TiO2-based materials [1]. Such a modification was used to prepare the BiVO4 electrodes for further Ni-based (NiOOH) electrocatalyst decorations [2]. The formed interfaces are studied using (photo)electrochemical and physicochemical methods to evaluate its activity towards oxygen evolution reaction. The results suggest, after tailored layer control, a comparable efficiency for the BiVO4 based on electrochemical deposition from aqueous solutions and methods based on organic solvents. Finally, electrochemical modification seemed to have a positive effect on the BiVO4 performance towards oxygen evolution. Thus, this work demonstrates a cheaper and simpler synthesis route for BiVO4 precursors and a simple method for activity modification without adding extra synthesis steps resulting in highly efficient BiVO4 photocatalysts.Figure 1. (upper left) Electrochemical setup for Bi deposition. (lower left) Cyclic voltammograms for Bi deposition. (Right) Photographs of several BiVO4 synthesis stages. Figure 1