摘要
Utilization of g-C 3 N 4 as a single photocatalyst material without combination with other semiconductor remains challenging. Herein, we report a facile green method for synthesizing a metal free modified g-C 3 N 4 photocatalyst. The modification process combines four different strategies in a one-pot thermal reaction: non-metal doping, porosity generation, functionalization with amino groups, and thermal oxidation etching. The as-prepared amino-functionalized ultrathin nanoporous boron-doped g-C 3 N 4 exhibited a high specific surface area of 143.2 m 2 g −1 which resulted in abundant adsorption sites for CO 2 and water molecules. The surface amino groups act as Lewis basic sites to adsorb acidic CO 2 molecules, which can also serve as active sites to facilitate hydrogen generation. Besides, the simultaneous use of ammonium chloride as a dynamic gas bubble template along with thermal oxidation etching efficiently boosts the delamination of the g-C 3 N 4 layers to produce ultrathin sheets; this leads to stronger light–matter interactions and efficient charge generation. Consequently, the newly modified g-C 3 N 4 achieved selective gas-phase CO 2 reduction into CO with a production yield of 21.95 µmol g −1 , in the absence of any cocatalyst. Moreover, a high hydrogen generation rate of 3800 µmol g -1 h −1 and prominent apparent quantum yield of 10.6% were recorded. This work opens up a new avenue to explore different rational modifications of g-C 3 N 4 nanosheets for the efficient production of clean energy.