Surface O2- regulation on POM electrocatalyst to achieve accurate 2e/4e-ORR control for H2O2 production and Zn-air battery assemble

Polyoxometalate is an excellent electracatalyst for oxygen reduction reaction. Here, to enhance its selectivity towards two-electron oxygen reduction reaction, one O2− is replaced by S2−. Vulcanized polyoxometalate exhibits two-electron feature in oxygen reduction reaction. The H2O2 production rate reaches 4.48 mol gcat-1 h-1 at 0.3 V (vs. RHE) with Faradaic efficiency 83.9 %. On the contrary, pure polyoxometalate without vulcanization shows typical four-electron character in oxygen reduction reaction and can be employed as cathode material in Zn-air battery. The results imply vulcanization weakens adsorption of OOH*, impedes O-O breaking and enhances two-electron selectivity. Vulcanized polyoxometalate exhibits photothermal induced advanced oxidation process, which can degrade various organic pollutants. Compared with traditional Fenton reaction, photothermal induced advanced oxidation process shows Fe2+ free character and wide pH scope. More importantly, this work also clarifies the influence of structure on oxygen reduction reaction selectivity for polyoxometalate.