Constructing p-d Orbital Hybridization via In Situ Generation of Bi19Br3S27/NiSx for Highly Selective Photothermal CO2 Reduction to C2H4.

Photothermal catalytic CO2 reduction to multi-carbon products is a promising approach for carbon utilization, yet the design of active sites that effectively promote multistep C─C coupling toward selective C2H4 formation remains a significant challenge. Hence, we employ an in situ interfacial engineering strategy to construct crystalline/amorphous Bi19Br3S27/NiSx (BBSN) photothermal catalysts with strong p-d orbital hybridization. The optimized BBSN-8 achieves a C2H4 production rate of 41.38 µmol g-1 h-1 with a selectivity of 96.8% under full-spectrum irradiation, which exhibits a remarkable advantage in the field of C2H4 production. Experimental results and theoretical calculations demonstrate that Ni incorporation optimizes CO2 adsorption from overly strong Bi─C single-site binding to balanced multi-sites adsorption, while newly formed p-d orbital hybridization establishes electronically cooperative Bi─S─Ni active sites stabilizing both carbon- and oxygen-centered species, synergistically facilitating *CO─CHO* coupling and boosting C2H4 formation. This work demonstrates that in situ interfacial orbital hybridization can regulate intermediate coupling and steer photothermal CO2 reduction toward highly selective C2H4 formation.