A WO3/BiVO4 photoanode coated with various metal oxides demonstrated high selectivity (faradaic efficiency) for hydrogen peroxide (H2O2) generation from water (H2O) under irradiation of simulated solar light in a highly concentrated hydrogen carbonate (KHCO3) aqueous solution. A mesoporous and amorphous aluminium oxide (Al2O3) layer significantly facilitated inhibition of the oxidative degradation of generated H2O2 into oxygen (O2) on the photoanode, resulting in unprecedented H2O2 selectivity (ca. 80%) and the accumulation (>2500 μM at 50C).
