S-scheme heterojunction Cu-porphyrin/TiO2 nanosheets with highly efficient photocatalytic reduction of CO2 in ambient air

Directly capturing CO 2 in ambient air and converting it into value-added fuels using photocatalysis is a potentially valuable technology. In this study, Cu-porphyrin (tetrakis-carboxyphenyl porphyrin copper, CuTCPP) was innovatively anchored on the surface of TiO 2 (titanium dioxide) nanosheets to form an S -scheme heterojunction. Based on this, a photocatalytic reaction system for stably converting CO 2 in ambient air into value-added fuels at the gas-solid interface was constructed without addition of sacrificial agents and alkaline liquids. Under the illumination of visible light and sunlight, the evolution rate of CO is 56 mu mol & sdot; g - 1 & sdot; h - 1 and 73 mu mol & sdot; g - 1 & sdot; h - 1 , respectively, with a potential CO 2 conversion rate of 35.8 % and 50.4 %. The enhanced of photocatalytic performance is attributed to the introduction of CuTCPP, which provides additional active sites, significantly improves capture capacity of CO 2 and the utilization of electrons. Additionally, the formation of S -scheme heterojunction expands the redox range and improves the separation efficiency of photo -generated charges.