A highly efficient BiVO4/WO3/W heterojunction photoanode for visible-light responsive dual photoelectrode photocatalytic fuel cell

Abstract

A highly efficient BiVO4/WO3/W heterojunction photoanode was fabricated based on the nanoporous WO3 film, which was prepared on the tungsten plate by anodic oxidation, in order to facilitate the electrons transfer from BiVO4 to WO3 by providing a natural connection between WO3 film and W substrate. Then, a visible-light responsive dual photoelectrode photocatalytic fuel cell (PFC) consisted of BiVO4/WO3/W photoanode and Pt modified commercial buried junction silicon (Pt/BJS) photocathode was constructed. The results showed that the optimized BiVO4/WO3/W photoanode obtained a photocurrent of 2.01mA/cm2 at 0.6V (vs Ag/AgCl) in 0.1M KH2PO4 (pH 7) electrolyte under simulated AM1.5 solar light, which was 180% and 205% higher than that of bare WO3 film and bare BiVO4 film, respectively. The established dual photoelectrode PFC showed high converting performance of organics into electricity. For example, a short-circuit current density of 0.26mAcm−2, which is higher than most of the reported visible-light responsive dual photoelectrode PFC systems, was obtained with the open-circuit voltage of 0.78V and maximum power output of 2.0×10−4 Wcm−2 in 20mgL−1 tetracycline hydrochloride. Furthermore, a removal ratio of 78% after 4h was achieved with a stable output photocurrent in the degradation process.