A novel visible-light responsive photocatalytic fuel cell with a heterostructured BiVO4/WO3 photoanode and a Pt/C air-breathing cathode

A series of heterostructured BiVO₄/WO₃ photoanodes were successfully prepared via a two-step method of hydrothermal deposition and impregnation. The optimized BiVO₄/WO₃ sample showed the highest photocurrent density of ∼880 μA/cm² at 0.8 V (vs Ag/AgCl) in 0.1 M KH₂PO₄ aqueous solution (pH 7) under simulated AM1.5 illumination. The optimized BiVO₄/WO₃ photoanode was coupled with a Pt/C air-breathing cathode to build up a visible-light responsive PFC system. The as-prepared PFC system showed outstanding photoelectrocatalytic performances in converting organics into electricity, and when glucose was used as the 'fuel', the maximum power density (P_max) and the short-circuit current density (I_sc) were 8.58 μW/cm² and 91.8 μA/cm², respectively. Degradation experiments showed that the removal rate of tetracycline hydrochloride in PFC with BiVO₄/WO₃ photoanode and Pt/C air-breathing cathode was ∼87.2% in 8 h, which was much higher than photolysis and photocatalysis process. The mechanism responsible for the enhanced photoelectrocatalytic performance of the as-prepared PFC system was also discussed.