In situ preparation of heterometallic polyphthalocyanine/ZnIn2S4 heterojunction for efficient photocatalytic CO2 reduction.

The photocatalytic reduction of carbon dioxide (CO2) using organic-inorganic heterojunctions represents a promising approach to achieving carbon neutrality and mitigating environmental pollution. Herein, we successfully synthesized a novel Z-scheme heterostructure by in situ growth of heterometallic polyphthalocyanine (FeCo3PPc) on the surface of ZnIn2S4 (ZIS). Specifically, the optimized FeCo3PPc/ZIS composite demonstrated efficient conversion of CO2 into CO and CH4 under visible light irradiation without the addition of sacrificial agents, achieving a CO production rate of 157.84 μmol g-1 under the condition of a 4 h reaction, representing a 5.23-fold increase compared to pristine FeCo3PPc and a 9.07-fold improvement relative to ZIS. Concurrently, CO selectivity achieved 96.37%. The performance enhancement is primarily attributed to the excellent visible-light absorption and efficient charge transport facilitated by the two-dimensional heterointerface. This work provides a theoretical foundation for the structural design of ZIS-based materials and demonstrates an approach for developing environmentally sustainable, highly efficient heterojunction photocatalysts.