Modulation of active center distance of hybrid perovskite for boosting photocatalytic reduction of carbon dioxide to ethylene

Solar-driven photocatalytic CO₂ reduction is an energy-efficient and sustainable strategy to mitigate CO₂ levels in the atmosphere. However, efficient and selective conversion of CO₂ into multi-carbon products, like C₂H₄, remains a great challenge due to slow multi-electron-proton transfer and sluggish C–C coupling. Herein, a two-dimensional thin-layered hybrid perovskite is fabricated through filling of oxygen into iodine vacancy in pristine DMASnI₃ (DMA = dimethylammonium). The rational-designed DMASnI₃(O) induces shrinkage of active sites distance and facilitates dimerization of C–C coupling of intermediates. Upon simulated solar irradiation, the DMASnI₃(O) photocatalyst achieves a high selectivity of 74.5%, corresponding to an impressive electron selectivity of 94.6%, for CO₂ to C₂H₄ conversion and an effective C₂H₄ yield of 11.2 μmol g⁻¹ h⁻¹. In addition, the DMASnI₃(O) inherits excellent water stability and implements long-term photocatalytic CO₂ reduction to C₂H₄ in a water medium. This work establishes a unique paradigm to convert CO₂ to C₂₊ hydrocarbons in a perovskite-based photocatalytic system.