Synergistic spin-polarization and ohmic contact in Co2 + doped ultrathin BiOCl nanosheets with Bi sub-nanoclusters for boosted CO2 photoreduction

The photocatalytic conversion of CO₂ into value-added chemicals using solar energy is a crucial strategy for achieving carbon neutrality. However, existing semiconductor catalyst systems suffer from suboptimal conversion efficiencies due to inefficient charge separation and transfer. The precise modulating surface microenvironment of semiconductor catalyst contributes an effective approach to address these limitations in photocatalytic applications. This study proposes a precise dual-modification strategy to modulate the surface microenvironment by incorporating Co 2+ incorporation and in situ generating Bi sub-nanoclusters in ultrathin BiOCl nanosheets. This approach synergistically establishes spin-polarization effects and interfacial ohmic contacts, while enhancing the intrinsic built-in electric field. Consequently, it drives efficient charge separation and transfer. Mechanistic analyses via theoretical simulations and in situ experiments reveal that the engineered spin polarization facilitates electron transfer through aligned magnetic moments, while the formed ohmic contact eliminates interfacial potential barriers, collectively lowering the energy barrier for CO 2 * and COOH* formation. The optimized 3 %Co-BBOC catalyst demonstrates exceptional CO₂-to-CO conversion performance with a production rate of 58.25 μmol·g −1 ·h −1 , representing a 6.6-fold enhancement over pristine BiOCl. The present work elucidates a dual-functional synergistic mechanism of modulating the surface microenvironment by integrating spin manipulation and interfacial engineering, providing fundamental insights for designing advanced photocatalytic systems with optimized charge transport and surface reaction dynamics.