Leaf-Vein structure like g-C3N4/P-MWNTs donor-accepter hybrid catalyst for efficient CO2 photoreduction

Separation efficiency of photogenerated carriers and CO2 adsorption ability of the catalyst are two important factors affecting the photoreduction performance of CO2. In view of the above analyses, leaf-vein like 2D-1D g-C3N4/P-MWNTs donor/acceptor semiconductor-carbon hybrid composite has been successfully prepared by the simple co-grinding/calcination processes. UV–vis DRS results showed that the modification of P-MWNTs can enhance the photo-absorption ability of the composite. Photoelectrochemical tests proved that 2D-1D Schottky-like barriers can enlarge the separation and transfer efficiency of photogenerated carriers. BET and CO2-adsorption tests exhibited that the introduction of P-MWNTs can greatly increase the CO2 capture ability of the composite. CO2 photoreduction experiments confirmed that the composite had much more excellent CO2 photoreduction performance than the pure g-C3N4 under the irradiation of UV–vis light or visible light. In-situ FTIR and 13C isotope tracer tests were applied to research the CO2 photoreduction processes. Finally, the synergistic effect on CO2 photoreduction process between electron transfer and CO2 adsorption behavior has been discussed in total.