Abstract
In this study, a heterojunction material composed of Keggin-type H(3)PMo(12)O(40) and BiOBr (PM/BOB) was synthesized by a hydrothermal-calcination method, and its photocatalytic CO(2) reduction performance and mechanism were investigated. Structural characterization through XRD, SEM, XPS, and UV-vis DRS revealed that calcination at 200 °C facilitated tight interfacial bonding between PM and BiOBr. The BiOBr sheets fragmented into nano-sized particles that uniformly integrated with PM, while partial reduction of PM generated active species containing mixed Mo(5+)/Mo(6+) valence states. Under optimal conditions, the t (200)-PM/BOB(0.5) composite demonstrated exceptional CO(2) reduction performance without sacrificial agents, achieving a CO production rate of 18.82 μmol g(-1) h(-1), representing 10.06-fold and 7.13-fold enhancements over pristine BiOBr and PM, respectively. Mechanistic studies unveiled a Z-scheme electron transfer pathway where the reduced-state intervalence charge transfer (IVCT) excited species in PM act as electron mediators to drive CO(2) reduction, while the BiOBr valence band holes participate in water oxidation, achieving spatial separation of redox sites. This work provides a novel strategy for designing efficient Keggin-type molybdenum-based photocatalysts and advances the development of solar-driven CO(2) utilization technologies.