BiOIO3 Nanoplates with Tailorable Surface Defects for Photocatalytic H2O2 Production

The integrated dual-channel pathway is regarded as an ideal process for photocatalytic H2O2 production. However, it is a key scientific challenge to rationally design photocatalysts for achieving H2O2 production through such a dual-channel pathway. Here, we designed surface oxygen vacancy-modified BiOIO3 (BIO-OVs-x) with spatially separated redox reaction centers by constructing a facet heterojunction for directly utilizing O2 and H2O to photosynthesize H2O2. Under white light irradiation, optimal BIO-OVs-2 exhibited the highest H2O2 production rate of 215.5 μmol g–1 h–1, which was 3 times more than that of BiOIO3, as well as an apparent quantum yield of 5.76% at 350 nm. Photoelectrochemical experiments confirmed that the introduction of oxygen vacancies boosted the efficiency of charge separation and transfer and adjusted the band structure. Control experiments and theoretical studies elucidated photocatalytic reaction active sites and the charge transport mechanism of BIO-OV catalysts. More importantly, the introduction of oxygen vacancies in BiOIO3 reduced the free energy for OH* of the water oxidation reaction and promoted the occurrence of the water oxidation reaction. This work provides a valuable basis for the fine design of a high-performance photocatalyst and for understanding the mechanism of hydrogen peroxide production.