Highly Hydrophilic and Defective Carbon Nitride for Enhanced Photocatalytic Hydrogen Evolution
Long Chen, Miao Li, Qinqin Xiao, Ying Yang, Peixian Huang, Xiaoqing Qiu
Abstract
Graphitic carbon nitride (g-C 3 N 4 ), as a kind of nonmetallic low-cost photocatalyst, has great potential in photocatalytic hydrogen (H 2 ) evolution, but its poor hydrophilicity and nonwetting extremely limit its H 2 evolution efficiency. Herein, highly hydrophilic and defective g-C 3 N 4 photocatalysts (NH 3 -CN-P as a representative example) have been fabricated on the basis of the strategy of joint phosphorus doping and ammonia stripping. The dopant of phosphorus prefers to occupy the C atoms bonded to -NH 2 groups in the g-C 3 N 4 skeleton, which is conducive to the formation of N defects caused by the effects of electronegativity and charge balance. Moreover, ammonia stripping plays a dual role in exposing plentiful two-dimensional defective planar structure and implanting the hydrophilic groups on the surface. As expected, the photocatalytic H 2 evolution property of NH 3 -CN-P reaches 11.31 mmol g –1 h –1, with an apparent quantum yield of 17.9% at 420 nm, outperforming the majority of the reported g-C 3 N 4 -based photocatalysts.