Direct Z-scheme copper cobaltite/covalent triazine-based framework heterojunction for efficient photocatalytic CO2 reduction under visible light

Photocatalytic conversion of CO2 into value-added chemical fuels with visible light provides a green method to relieve the challenges of the energy crisis and environmental problems. Developing highly efficient photocatalysts is essential to achieve this technology. Herein, we designed and successfully synthesized copper cobaltite/covalent triazine-based framework (CuCo2O4/CTF-1) Z-scheme heterojunction catalysts for photocatalytic CO2 reduction. The obtained CuCo2O4/CTF-1 composites exhibited enhanced photocatalytic CO production activity. The optimal properties were 12.7-fold and 11.6-fold higher than those of pure CTF-1 and CuCo2O4, respectively. According to the analysis of UV-vis diffuse reflectance spectra, CO2 uptake isotherms, electrochemical impedance spectroscopy and transient photocurrent responses, the enhanced photocatalytic CO production performance of CuCo2O4/CTF-1 composites can be ascribed to its enhanced visible light absorption and CO2 adsorption capability, increased spatial separation of photoinduced charge carriers, and optimized redox ability resulting from the direct Z-scheme CuCo2O4/CTF-1 heterojunction. This work offers a novel strategy for designing and constructing CTF-based direct Z-scheme heterojunction photocatalysts for photocatalytic CO2 conversion to chemical energy fuels.