In situ synthesis of an S-scheme COF-5@CsPbBr3 heterojunction for efficient photocatalytic CO2 reduction

Abstract

The construction of heterojunction photocatalysts has attracted significant attention due to their ability to accelerate the migration of photogenerated charge carriers and suppress the recombination of photogenerated electron–hole pairs. However, photocatalytic efficiency remains constrained by insufficient redox capability. Herein, an organic–inorganic S-scheme COF-5@CsPbBr₃ heterojunction is fabricated by the in situ growth of CsPbBr₃ QDs on a COF-5 substrate, which enhances the migration efficiency of photogenerated charge carriers and the redox capacity. Compared to pristine COF-5 and CsPbBr₃ QDs, the COF-5@CsPbBr₃ heterojunction exhibited an obviously broader light-harvesting range, higher photocatalytic activity, and better stability. Furthermore, band structure analysis revealed that strong interfacial interactions between COF-5 and CsPbBr₃ QDs resulted in the formation of hybrid energy levels, facilitating the transfer of photogenerated electrons from COF-5 to CsPbBr₃ QDs. Under visible-light irradiation, the CO production rate reached 263.51 μmol g⁻¹ without additional photosensitizers and cocatalysts. This work demonstrates that constructing S-scheme heterojunction photocatalysts represents an effective strategy for improving the efficiency of photocatalytic CO₂ reduction.