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 MxOy@Bi2S3 heterojunctions in which the MxOy@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 MxOy@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 MxOy@Bi2S3 heterojunctions. Therefore, all the MxOy@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.