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

Ethylene production by CO 2 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 C 2 products currently. Herein, an amorphous Cu x CoS y composed of the minority crystalline CuCo 2 S 4 is fabricated to realize an excellent C 2 H 4 selectivity in terms of R electron (94.9%). Unsaturated Co and S play the key roles in the improved efficiency of C 2 H 4 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 *CH 2 = C. This work paves a new way for broadening the efficient of C 2 H 4 photocatalytic evolution using amorphous photocatalyst.