Dip-coating synthesis of P-doped BiVO4 photoanodes with enhanced photoelectrochemical performance

The application of bismuth vanadate for photoelectrochemical water splitting is limited by the insufficient charge separation and transport characteristics. In this work, phosphorus doped BiVO4 (P-BiVO4) photoanodes were fabricated through dip-coating method and subsequent thermal treatment process. The optimized 2% P-BiVO4 exhibited a photocurrent density up to 0.28 mA/cm(2) at 1.23 V versus reversible hydrogen electrode in 0.5 M Na2SO4 electrolyte (AM 1.5 G, 100 mW/cm(2)). The incident photon-to-current efficiency of 2% P-BiVO4 was boosted to 33%, which was significantly higher than the pristine BiVO4 photoanode. The X-ray photoelectron spectra indicate that the P-BiVO4 possessed abundant oxygen vacancies, which can account for enhancing PEC performance of P-BiVO4. The electrochemical impedance spectroscopy and Mott-Schottky results further show that P-BiVO4 possess less interface obstruction and high carrier concentration, which were beneficial for the improvement of photoelectrochemical performance. This work provides a useful guidance for the design of non-metal doped BiVO4 photoanodes for energy conversion. (C) 2018 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers.