Constructing a Cu: MoO3/g-C3N4 heterostructure with broad visible-light response to enhance CO2-to-methanol conversion performance

A Cu: MoO 3 /g-C 3 N 4 binary heterojunction photocatalyst was synthesized via a hydrothermal method, achieving a light response that covers nearly the entire visible region. The material shows a strong, broad absorption band from 400 to 700 nm, significantly improving its visible-light harvesting and utilization efficiency. Optimization of the g-C 3 N 4 , Cu, and Mo molar ratios further enhanced the catalyst’s redox performance under visible-light irradiation. Through combined XPS, UV–vis, and in situ DRIFTS characterizations, it was verified that the Cu: MoO 3 /g-C 3 N 4 photocatalyst possesses a wide visible-light absorption range and effectively transforms absorbed long-wavelength photons into photogenerated electron-hole pairs, thereby facilitating the separation and transfer of charge carriers. Due to the simultaneous enhancement of broad-spectrum light capture and charge separation/transfer efficiency, this catalyst demonstrates excellent catalytic activity in visible light-driven CO 2 conversion, with a maximum methanol production rate of 102.52 μmol·g −1 ·h −1 . This work verifies the feasibility of efficient visible light-driven CO 2 conversion and provides a viable design approach and reference for constructing multi-metal-based photocatalysts with full visible light response.