Phosphorus-Doped Hollow Tubular g-C3N4 for Enhanced Photocatalytic CO2 Reduction

Photocatalytic CO2reduction is a tactic for solving the environmental pollution caused by greenhouse gases. Herein, NH4H2PO4was added as a phosphorus source in the process of the hydrothermal treatment of melamine for the first time, and phosphorus-doped hollow tubular g-C3N4(x-P-HCN) was fabricated and used for photocatalytic CO2reduction. Here, 1.0-P-HCN exhibited the largest CO production rate of 9.00 μmol·g−1·h−1, which was 10.22 times higher than that of bulk g-C3N4. After doping with phosphorus, the light absorption range, the CO2adsorption capacity, and the specific surface area of the 1.0-P-HCN sample were greatly improved. In addition, the separation of photogenerated electron–hole pairs was enhanced. Furthermore, the phosphorus-doped g-C3N4effectively activated the CO2adsorbed on the surface of phosphorus-doped g-C3N4photocatalysts, which greatly enhanced the CO production rate of photocatalytic CO2reduction over that of g-C3N4.