Solar-Driven One-Compartment Hydrogen Peroxide-Photofuel Cell Using Bismuth Vanadate Photoanode

One-compartment H₂O₂-photofuel cells using monoclinic scheelite BiVO₄ film deposited on fluorine-doped tin oxide (ms-BiVO₄/FTO) as the photoanode, Prussian blue film-coated FTO cathode, and deaerated aqueous electrolyte solution of 0.1 M NaClO₄ and 0.1 M H₂O₂ were constructed. Mesoporous TiO₂ photoanode cells with the same cathode and electrolyte solution were also prepared for comparison. The ms-BiVO₄/FTO photoanode was prepared by a two-step route consisting of spin coating of a precursor solution on FTO and subsequent heating at 500 °C in the air. The thickness of the ms-BiVO₄ film was controlled in the range from 50 to 500 nm by the number of the spin-coating times. There is an optimum thickness of the ms-BiVO₄ film in the cell performances under illumination of simulated sunlight (AM 1.5, 100 mW cm^-2, 1 sun). Under the optimum conditions, the ms-BiVO₄/FTO photoanode cell provides a short-circuit current (J _sc) = 0.81 mA cm^-2 and an open-circuit voltage (V _oc) = 0.61 V, far surpassing the values of J _sc = 0.01 mA cm^-2 and V _oc = 0.31 V for the conventional mesoporous TiO₂ photoanode cell. The striking cell performance is ascribable to the high visible-light activity of ms-BiVO₄ for H₂O₂ oxidation and its low thermocatalytic activity for the decomposition.