Regulating *COOH/*CHO Intermediate for Selective Photocatalytic CO 2 Reduction under Infrared Light

Most photocatalysts for CO 2 reduction can only respond to ultraviolet and visible light, while infrared light-responsive photocatalysts remain scarce. In particular, converting CO 2 into CH 4 is a complex process involving the transfer of eight electrons, and its activity is often compromised by side reactions. Herein, we developed an organic−inorganic hybrid heterojunction with sulfur vacancies of In 2 S 3 -cobalt porphyrin ([meso-tetra(4-sulfonatophenyl)porphyrin], CoTPPS). This heterojunction was achieved by assembling tubular MIL-68(In)-derived In 2 S 3 with CoTPPS via coordination interaction, achieving precise control over *COOH/*CHO intermediates to regulate CH 4 selectivity. The optimized In 2 S 3 -CoTPPS exhibits a CO evolution rate of 38.84 μmol g −1 h −1, which is 5.43 times that of pure In 2 S 3 (7.15 μmol g −1 h −1 ). Moreover, In 2 S 3 -CoTPPS demonstrates a high CH 4 evolution rate of 36.65 μmol g −1 h −1 under infrared light (λ = 800−1100 nm). The enhanced catalytic performance is attributed to the improved light absorption, optimized CO 2 adsorption and activation capabilities, and facilitated charge carrier separation by the heterojunction. Density functional theory calculations also indicate that the heterojunction reduces the energy barrier of the key intermediate (*COOH) and the Gibbs-free energy of the *+CO 2 → *CHO transformation, thereby promoting the selective formation of multiple products. This study provides a research idea for the preparation of infrared light-responsive photocatalysts.