CO2 Photoreduction into C2 Fuels Steered by Heteroatom Pair Sites in MxOy@Bi2S3 Heterojunction

Synthesis of ethylene (C₂H₄) through carbon dioxide (CO₂) photoreduction is predominantly constrained by the kinetic difficulties in C–C coupling. Herein, we develop a universal strategy for C₂H₄ synthesis from CO₂ photoreduction over a series of M_xO_y@Bi₂S₃ heterojunctions in which the M_xO_y@Bi₂S₃ heterojunction contain charge-asymmetrical M–Bi pair sites for enhanced C–C coupling. As a prototype, Bi₂S₃ nanorod-based heterojunctions with wide-period and multigroup metal oxides (Bi₂O₃@Bi₂S₃, In₂O₃@Bi₂S₃, ZnO@Bi₂S₃, and SnO₂@Bi₂S₃ heterojunctions) are synthesized through a simple and effective strategy. Bader charge calculations confirm the presence of charge-asymmetrical M–Bi pair sites at the interface of the M_xO_y@Bi₂S₃ heterojunction Further density functional theory (DFT) computations disclose that the C–C coupling turns from a nonspontaneous endothermic process to a spontaneous exothermic process after the construction of heterojunctions, suggesting the feasibility of generating C₂ products through CO₂ photoreduction on M_xO_y@Bi₂S₃ heterojunctions. Therefore, all the M_xO_y@Bi₂S₃ heterojunction can realize CO₂ photoreduction into C₂H₄, whereas the individual Bi₂O₃, In₂O₃, ZnO, and SnO₂ nanoparticles can only produce carbon monoxide as their product. This proposed universal strategy is expected to prepare a highly active heterojunction for C₂H₄ photosynthesis from CO₂ reduction.