Excellent performance of water oxidation at low bias potential achieved by transparent WO3/BiVO4 photoanode integrated with molecular nickel porphyrin

摘要

In attempt to gain a high efficiency of water splitting at 0.6 V (vs. RHE) with a photoanode for the dual illuminated tandem device design, an ultra-thin transparent WO3/BiVO4 composite photoanode was prepared by spin-coating technology. Incorporation of molecular nickel porphyrin as water oxidation catalyst into the prepared WO3/BiVO4 photoanode greatly promoted the efficiency of hole injection (eta(ox)) into the electrolyte. A photocurrent density of 0.26 mA cm(-2) was achieved by the hybrid photoanode at 0.6 V (vs. RHE), corresponding to the value of eta(ox) to be 45%. The stability of nickel porphyrin on the WO3/BiVO4 photoanode was investigated by photolysis at 0.82 V (vs. RHE), where the maximum applied bias photon-to-current efficiency for the WO3/BiVO4/NiTCPP photoanode was obtained.