BiOIO₃ Nanoplates with Tailorable Surface Defects for Photocatalytic H₂O₂ Production

The integrated dual-channel pathway is regarded as an ideal process for photocatalytic H 2 O 2 production. However, it is a key scientific challenge to rationally design photocatalysts for achieving H 2 O 2 production through such a dual-channel pathway. Here, we designed surface oxygen vacancy-modified BiOIO 3 (BIO-OVs- x ) with spatially separated redox reaction centers by constructing a facet heterojunction for directly utilizing O 2 and H 2 O to photosynthesize H 2 O 2 . Under white light irradiation, optimal BIO-OVs-2 exhibited the highest H 2 O 2 production rate of 215.5 μmol g –1 h –1, which was 3 times more than that of BiOIO 3, 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 BiOIO 3 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.