Evaluating the Reactivity of BiVO4 Surfaces for Efficient Electrocatalytic H2O2 Production: A Combined Experimental and Computational Study

Three BiVO4 morphologies, varying in the surface ratios corresponding to high and low index planes, (−121) and (040), respectively, were synthesized and directly grown on a conducting substrate. These three different substrates were evaluated for electrochemical water oxidation reaction to preferentially form hydrogen peroxide at the anode. Experimental results show that the prevalence of high-index plane (−121) contributes favourably for producing H2O2, against O2 formation. Furthermore, density functional theory studies show that the adsorption behavior of HCO3 species on these high-index surfaces lends to a possible explanation that accounts for better stability of the evolving H2O2 molecules. The HCO3 species adsorbed on the low-index surface are shown to contribute to a pathway that leads to the decomposition of the H2O2 molecule. This observation is purported to contribute to a lower H2O2 generation efficiency for low index facets. These important differences on the two surfaces, brought about by th...