Promoted selectivity of photocatalytic CO2 reduction to C2H4 via hybrid CuxCoSy possessing dual unsaturated sites

Abstract

Ethylene production by CO₂ reduction is sluggish because the repulsive dipole-dipole interaction and 12 proton-coupled electron-transfer steps consecutively. Amorphous structured photocatalysts possess few grain boundaries and abundant unsaturated sites, accelerating the reaction efficiency from the angle of dynamics and thermodynamics, which still not yet be used in PCR to C₂ products currently. Herein, an amorphous Cu_xCoS_y composed of the minority crystalline CuCo₂S₄ is fabricated to realize an excellent C₂H₄ selectivity in terms of R_electron (94.9%). Unsaturated Co and S play the key roles in the improved efficiency of C₂H₄ generation. C-C coupling is achieved via shortening Co-S bonds distance, and *CO-*CO coupling barrier is decreased by more electrons accumulated on unsaturated S. Water is adsorbed on Co adjacent to S and provide protons for *COCO to form *CH₂ = C. This work paves a new way for broadening the efficient of C₂H₄ photocatalytic evolution using amorphous photocatalyst.