Boosting photoelectrochemical performance of BiVO4 by borate buffer activation: the role of trace iron impurities

Abstract

BiVO4 is an attractive photoanode material for water oxidation, which requires surface treatment to improve energy efficiency and stability. Herein, we investigate the role of borate buffer in activating BiVO4 photoanode. We found that trace iron impurities in borate buffer play a critical role in activating the photoanode. By optimizing the activation conditions, the photocurrent density attains 4.5 mA/cm2 at 1.23 VRHE without any cocatalysts, alongside a high ABPE value of 1.5 % at 0.7 VRHE. Our study discloses the role of iron in the activation effect of borate buffer on BiVO4 photoanode, which has implications for other catalytic systems.