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

Most photocatalysts for CO2 reduction can only respond to ultraviolet and visible light, while infrared light-responsive photocatalysts remain scarce. In particular, converting CO2 into CH4 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 In2S3-cobalt porphyrin ([meso-tetra(4-sulfonatophenyl)porphyrin], CoTPPS). This heterojunction was achieved by assembling tubular MIL-68(In)-derived In2S3 with CoTPPS via coordination interaction, achieving precise control over *COOH/*CHO intermediates to regulate CH4 selectivity. The optimized In2S3-CoTPPS exhibits a CO evolution rate of 38.84 μmol g−1 h−1, which is 5.43 times that of pure In2S3 (7.15 μmol g−1 h−1). Moreover, In2S3-CoTPPS demonstrates a high CH4 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 CO2 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 *+CO2→ *CHO transformation, thereby promoting the selective formation of multiple products. This study provides a research idea for the preparation of infrared light-responsive photocatalysts.