Rational design of W-doped BiVO4 photoanode coupled with FeOOH for highly efficient photoelectrochemical catalyzing water oxidation

Abstract

Developments of promising photocatalyst for PEC water oxidation gain significant interest in the research field of PEC water splitting. The BiVO4 has been envisioned as suitable photocatalyst material for the PEC water oxidation due to suitable bandgap with favorable band edge positions. Nevertheless, the poor electron-hole separation and low charge transfer efficiency of BiVO4 yield sluggish surface catalysis reaction. Herein, facile electrodeposition and annealing techniques are proposed to fabricate W-doped BiVO4 photoanode coupled with FeOOH (W–BiVO4/FeOOH) for efficient photocatalytic water oxidation. This synthesis is simple, cost-effective and less time consuming. The doping concentration of W and deposition time of FeOOH are optimized to improve photocatalytic ability of BiVO4. At 1.23 V vs. reversible hydrogen electrode (RHE) under 1 sun illumination, the W–BiVO4/FeOOH photoanode exhibits a high photocurrent density of 2.2 mA/cm2, which is seven folds higher than that of the pristine BiVO4 photoanode (0.31 mA/cm2 1.23 V vs. RHE). The enhanced photocatalytic ability of W–BiVO4/FeOOH photoanode is due to the enhanced charge transport properties and synergistic effects of W doping and FeOOH deposition. The excellent long-term stability with the photocurrent density retention of 90% after continuous light illumination for 1000 s is also achieved for the W–BiVO4/FeOOH photoanode.