In-situ construction of BiOBr/UiO-66(Zr/Ce) S-scheme heterojunction for efficient selective photocatalytic CO2 reduction to CO

• BiOBr/UiO-66 (Zr/Ce) S-scheme heterojunction was successfully synthesized. • BiOBr/UiO-66 (Zr/Ce) shows excellent selective photocatalytic CO 2 reduction to CO. • Ce 3+ /Ce 4+ redox pair effectively reduces recombination of photogenerated carriers . • Photocatalytic mechanism of BiOBr/UiO-66 (Zr/Ce) S-scheme heterojunction was proposed. Photocatalytic CO 2 reduction has significant potential in driving carbon fuel conversion. However, the majority of photocatalysts face challenges such as limited product selectivity, poor catalytic behavior, and bad cycle stability. In this paper, an in situ solvothermal method is proposed to synthesize BiOBr/UiO-66(Zr/Ce) composites. During this process, bimetallic UiO-66(Zr/Ce) is modified onto BiOBr , leading to a notable enhancement in the efficiency of photocatalytic CO 2 reduction. Under simulated solar conditions, the optimized 10-BiOBr/UiO-66(Zr/Ce) showed a CO yield of 94.89 μmol·g −1 ·h −1 with an 82.89 % selectivity. Notably, the electron consumption rate (R electron ) of 228.98 μmol·g −1 ·h −1 exceeded that of BiOBr and UiO-66 (Zr/Ce) by factors of 10.2 and 10.4, respectively. Meanwhile, the 10-BiOBr/UiO-66(Zr/Ce) composite demonstrated excellent stability over multiple catalytic cycles. The superior performance of the BiOBr/UiO-66(Zr/Ce) heterojunction stems from its close interfacial contact, which promotes interfacial electron transfer and space charge separation. In addition, the common mechanism of Ce 4+ /Ce 3+ redox cycling and S-scheme heterojunction greatly maintains the strong redox capacity of the photogenerated carriers. This study demonstrates its great potential in photocatalytic CO 2 reduction and provides a new strategy for designing stable and efficient catalysts.