Phosphorus-Doped Hollow Tubular g-C 3 N 4 for Enhanced Photocatalytic CO 2 Reduction.

Photocatalytic CO 2 reduction is a tactic for solving the environmental pollution caused by greenhouse gases. Herein, NH 4 H 2 PO 4 was added as a phosphorus source in the process of the hydrothermal treatment of melamine for the first time, and phosphorus-doped hollow tubular g-C 3 N 4 (x-P-HCN) was fabricated and used for photocatalytic CO 2 reduction. 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-C 3 N 4 . After doping with phosphorus, the light absorption range, the CO 2 adsorption 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-C 3 N 4 effectively activated the CO 2 adsorbed on the surface of phosphorus-doped g-C 3 N 4 photocatalysts, which greatly enhanced the CO production rate of photocatalytic CO 2 reduction over that of g-C 3 N 4 .