Interfacial engineering regulating the electronic structure of cobalt active sites in hollow Co3S4/In2S3 for enhanced photothermal catalytic cycloaddition of diluted CO2

Abstract

The photocatalytic conversion of diluted CO₂ (15 vol%) into cyclic carbonates is highly desirable, but it remains a significant challenge due to insufficient modulation of the microscopic chemical environment at the catalyst interfaces and sluggish activation kinetics. In this work, we develop an interfacial engineering strategy for preparing a hollow Co₃S₄/In₂S₃ heterojunction, which exhibits enhanced performance in photothermal catalytic CO₂ cycloaddition. The Co₃S₄/In₂S₃ heterojunction features a unique “light-trapping” cavity that maximizes photon harvesting, coupled with a robust built-in electric field (BEF) that facilitates electron transfer from In₂S₃ to Co₃S₄ at the heterointerface. Catalyst characterization reveals that BEF promotes the efficient separation of photogenerated charges, while the regulated Co active sites significantly enhance the adsorption and activation of epoxide as well as CO₂. Density functional theory (DFT) calculations and spectroscopic studies confirm that Co active sites facilitate CO₂ activation, while the efficient migration and separation capabilities of photogenerated carriers in Co₃S₄/In₂S₃ heterojunctions promote the transfer of photogenerated electrons from the catalyst to the reactants. Consequently, the Co₃S₄/In₂S₃(130,4) exhibits a remarkable 91% yield of chloropropene carbonate even under diluted CO₂ conditions (CO₂/N₂ = 15 : 85%), driven by a synergistic photothermal mechanism. Mechanistic studies reveal that Co₃S₄/In₂S₃(130,4) significantly reduces the energy barrier of the rate-limiting step, thereby increasing catalytic efficiency. This work provides new insights into the design of high-performance heterojunction photocatalysts by coupling morphological design with interfacial engineering for the efficient conversion of CO₂ into value-added chemicals.