Mo-doping and CoOx loading over BiVO4 photoanode for enhancing performance of H2O2 synthesis and in-situ organic pollutant degradation

The combination of photoelectrochemical water oxidation hydrogen peroxide (H2O2) on the anode and hydrogen evolution on the cathode increase the value of the water splitting process. However, the sluggish water oxidation kinetics and slow carrier transport limit the generation of H2O2. In this study, to promote H2O2 production, the surface of a Mo doped BiVO4 photoanode was modified with CoOxco-catalyst. The resulting CoOx/Mo-BiVO4 photoanode generates H2O2 at a rate of 0.39 mu mol min-1 cm-2 with a selectivity of 76.9% at 1.7 V RHE . The experimental results indicate that CoOx decorated on Mo-BiVO4 kinetically favors the H2O2 production via reduced band bending, while inhibiting H2O2 decomposition. According to density functional theory calculations, the loading of CoOx enhances the efficiency of the Mo-BiVO4 photoanode in generating H2O2. Moreover, the in-situ generated H2O2 through CoOx/Mo-BiVO4 was applied to the degradation of tetracycline in aqueous solution, finding that CoOx/Mo-BiVO4 exhibits the best performance among the catalysts evaluated. This work demonstrates that the CoOxco-catalyst can effectively facilitate the water oxidation to H2O2, opening a way for its application in situ water remediation. (c) 2024, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.