Enhanced photocatalytic CO2 reduction via synergistic crystal plane engineering and heterojunction effects in BiOBr/CeO2: charge separation efficiency and mechanism

The modulation of the catalyst microstructure to facilitate the directional migration of photogenerated charge carriers represents an effective strategy for boosting photocatalytic activity. Based on the synergistic effects of crystal plane engineering and heterostructure modification, a series of BiOBr/CeO 2 S-scheme heterojunctions were fabricated for photocatalytic CO 2 reduction. By systematically regulating the exposed crystal facets and component ratios of CeO 2 , the interfacial interactions and electron transmission were optimized. Therein, the rod-like CeO 2 (R), predominantly exposing (110) facets, formed an intimately contacted interface with BiOBr, which significantly improved the charge separation efficiency. The abundant oxygen vacancies and unique S-scheme electron transfer pathway within the BiOBr/CeO 2 (R) nanocomposite cooperatively promoted CO 2 photoreduction by efficiently restraining carrier recombination and enhancing the utilization of photogenerated electrons. The corresponding catalyst BC-40(R) exhibited the best CO evolution rate of 131.8 μmol·g −1 ·h −1 , which was 8.8 times higher than that of pure CeO 2 (R). Furthermore, density functional theory (DFT) calculations further verified the charge transport pathways within the heterostructure. This study demonstrates the strategic integration of crystal facet engineering with S-scheme heterojunction, providing fundamental insights into the rational design of advanced photocatalysts.