Constructing p‐d Orbital Hybridization via In Situ Generation of Bi 19 Br 3 S 27 /NiS x for Highly Selective Photothermal CO 2 Reduction to C 2 H 4

ABSTRACT Photothermal catalytic CO 2 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 C 2 H 4 formation remains a significant challenge. Hence, we employ an in situ interfacial engineering strategy to construct crystalline/amorphous Bi 19 Br 3 S 27 /NiS x (BBSN) photothermal catalysts with strong p‐d orbital hybridization. The optimized BBSN‐8 achieves a C 2 H 4 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 C 2 H 4 production. Experimental results and theoretical calculations demonstrate that Ni incorporation optimizes CO 2 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 C 2 H 4 formation. This work demonstrates that in situ interfacial orbital hybridization can regulate intermediate coupling and steer photothermal CO 2 reduction toward highly selective C 2 H 4 formation.