Double Halide Perovskite Heterojunction Coupled with Molecular Cobalt Catalyst Achieves Highly Efficient CO2 Photoreduction

The excessive combustion of traditional fossil fuels has led to severe global warming, primarily due to increased carbon dioxide (CO₂) emissions, and has also triggered an energy crisis. Photocatalytic conversion of CO₂ into fuel is emerging as one of the most promising strategies for mitigating these issues. In this study, lead-free halide perovskites Cs₂AgBiBr₆(CABB) and Cs₂PdBr₆(CPB) were utilized to construct a heterostructure, where cobalt phthalocyanine (CoPc) was anchored onto halide perovskites through an amino group linkage. This CoPc@CABB/CPB system achieved a CO yield of 164 µmol·g⁻¹, which is 3.8 times higher than that of pure CABB and surpasses the performance of most reported CABB-based photocatalysts. The formation of a heterojunction with CPB significantly improved charge separation efficiency and CO₂ reduction efficiency. Precise anchoring of the amino group of CoPc to Br improved light absorption capacity, thereby enhancing photocatalytic CO₂ reduction capacity. This work presents an efficient and environmentally friendly approach for CO₂ reduction using perovskite-based photocatalysts.