Value-added conversion of CO2 using solar energy is a sustainable strategy to address the energy crisis and environmental issues simultaneously. In this work, Cu–CuO/NC catalysts were successfully prepared by a sol-gel method, and the effects of Cu doping ratio and heat treatment temperature on the catalyst properties were investigated. The experimental results revealed that 7%CNC-600 °C has the best photocatalytic reduction performance of CO2 to CH3OH within 8h, 812μmol/gcat. The catalysts were also analyzed using techniques such as XRD, SEM, TEM, Raman spectroscopy, CO2-TPD, PL, etc. The superior catalytic activity mainly benefits from the electron capture properties of the metal and its synergistic effect with nitrogen-doped carbon, resulting in a significantly improved catalyst optical property, enhanced CO2 adsorption capacity, and improved separation efficiency of photoexcited charges. Furthermore, the combined DRS and VB-XPS results elucidate the photocatalytic reaction mechanism. This study could provide potential strategies for environmental purification and energy conversion.