Enhanced and Selective Photocatalytic Reduction of CO2 to CH4 Using a Pt-Loaded CuPc/g-C3N4 Z-Scheme Heterojunction Catalyst

In this study, a novel Pt-loaded CuPc/g-C 3 N 4 (PtCuCN) composite was synthesized for the selective photocatalytic reduction of CO 2 to CH 4 under visible light. The PtCuCN catalyst achieved a CH 4 yield of 39.8 μmol g⁻ 1 h⁻ 1 , significantly outperforming bulk g-C₃N₄ and CuPc alone by factors of 2.5 and 3.1, respectively, with a high selectivity of 90%. In comparison with other commonly studied photocatalysts, such as g-C 3 N 4 -based catalysts, the PtCuCN composite exhibited superior CH 4 yield and product selectivity, demonstrating its potential as a more efficient photocatalyst for CO₂ reduction. X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations, and in-situ infrared (IR) analysis revealed that the Pt⁰ species effectively lower the activation energy for CH 4 formation, while CuPc extends the light absorption range and enhances charge separation. The combined effects of these components in a Z-scheme heterojunction provide new insights into designing highly selective CO 2 -to-CH 4 photocatalysts. This work demonstrates the potential of PtCuCN as a highly efficient and stable catalyst for CO 2 reduction to CH 4 under visible light.