Enhanced photoreduction CO2 activity on g-C3N4: By synergistic effect of nitrogen defective-enriched and porous structure, and mechanism insights

A novel porous structure g-C3N4 with nitrogen defect photocatalysts (DCN-P) was successfully prepared by insitu doping strategy and freeze-dried method, it exhibits enhanced photo-reduction CO2 performance with satisfactory CO, CH4 productivity about 19.7 umol g(-1), 37.1 umol g(-1), which is more higher than that of bulk g-C3N4 (B-CN). Systematically characterization demonstrated that the synergistic effect of unique porous structure and the nitrogen defection in DCN-P can effect enhance CO2 adsorption, increase reactive sites, improve optical absorption and narrowed band gap of g-C3N4, which is supported by both experimental and density functional theory (DFT) calculations results. More importantly, this work provides a new ideas for constructing other highperformance metal-free photocatalytic systems for CO2 reduction.