Novel plate-on-plate hollow structured BiOBr/Bi2MoO6 p-n heterojunctions: In-situ chemical etching preparation and highly improved photocatalytic antibacterial activity

BiOBr/Bi 2 MoO 6 p-n heterojunction with plate-on-plate hollow structure and greatly efficient photocatalytic antibacterial activity was successfully fabricated via a chemical etching and in-situ growth process. • Novel plate-on-plate hollow structured BiOBr/Bi 2 MoO 6 p-n heterojunctions with rich OVs were constructed by an in-situ chemical etching method. • BM PHs were formed by ion exchange and in-situ growth of Bi 2 MoO 6 on BiOBr nanoplates through Ostwald ripening process. • BM PHs displayed a highly improved visible-light photocatalytic disinfection activity. • The formation of p-n heterostructure and massive OVs synergistically resulted in the fast separation of photogenerated charge carriers. • OH, O 2 − and h + played main roles in the photocatalytic reaction for BM PHs. In this study, a novel plate-on-plate hollow structured BiOBr/Bi 2 MoO 6 p-n heterojunction with rich oxygen vacancies (OVs) was systematically constructed by an in-situ ion exchange method. The structure, morphology, photoabsorption ability, and surface properties of BiOBr/Bi 2 MoO 6 were characterized, showing an etching process of BiOBr nanoplates (NPs) by molybdate to form BiOBr/Bi 2 MoO 6 plate-on-plate hollow heterostructures (BM PHs). A feasible formation mechanism was proposed by regulating the concentration of molybdate and reaction times. The introduction of Bi 2 MoO 6 in BiOBr NPs was proved to play a significant role in affecting the crystal growth and photocatalytic activity of BM PHs, which displayed a greatly enhanced photocatalytic antibacterial performance under visible light irradiation compared to pure BiOBr and Bi 2 MoO 6 . The highly efficient photocatalytic performance can be attributed to the synergistic effects of the fabricated p-n heterojunction combined with massive OVs, leading to the fast separation of photoinduced charge carriers, which were subsequently verified by the photoelectrochemistry (PEC) and photoluminescence (PL) measurements. In addition, the photocatalytic mechanism was discussed and deduced based on the active spices trapping and electron spin resonance (ESR) tests as well as DFT theory calculation, illustrating the primary roles of OH, O 2 − and h + and charge migration route during the photocatalytic process of BM PHs. This study provides a promising strategy for constructing novel heterojunctions with highly efficient photocatalytic performance.