Vacancy Pair-Induced Charge Rebalancing with Surface and Interfacial Dual Polarization for CO₂Photoreduction

Poor charge kinetics greatly reduce the efficiency of photocatalytic CO₂reduction. Herein, a synchronous surface and interfacial dual polarization strategy was developed to promote charge separation. Bi-O vacancy pairs in Bi₂₄O₃₁Br₁₀atomic layers can trigger strong coupling between black phosphorus (BP) and Bi₂₄O₃₁Br₁₀, forming a restructured closely contacted BP-Bi₂₄O₃₁Br₁₀configuration with a charge-redistributed interface via electronegativity-induced charge rebalancing. The Bi-O vacancy pairs on the surface of Bi₂₄O₃₁Br₁₀and restructured BP/Bi₂₄O₃₁Br₁₀interface enable synchronous surface and interfacial dual polarization, creating an electronic bridge from the interior of Bi₂₄O₃₁Br₁₀to the BP surface, as proven by ultrafast transient absorption spectroscopy. This configuration favors a low CO₂activation energy barrier, effectively stabilizes COOH∗ intermediates, and decreases the rate-determining step energy barrier. Benefiting from these features, the stable CO generation rate of optimized BP-Bi₂₄O₃₁Br₁₀reaches up to 39.8 μmol g^-1h^-1via CO₂photoreduction in water, which is 2.4 and 46.8 times higher than those of defective Bi₂₄O₃₁Br₁₀atomic layers and defect-poor Bi₂₄O₃₁Br₁₀, respectively. This study provides insights into the synchronous design of surface defects and restructured interfaces for dual polarization.