Template-Assisted Surface Hydrophilicity of Graphitic Carbon Nitride for Enhanced Photocatalytic H2 Evolution

Grafting organic groups with different electronegativities or conjugation properties on the surface of polymeric organic materials is an effective route to improving the electron structure and the charge separation. Introducing catalytic active sites on the surface of carbon nitride, such as defect creation and functional group coupling, has been developed to hinder recombination of photogenerated carriers. Herein, we report, for the first time, the fabrication of a surface-functionalized porous carbon nitride with remarkable water adsorption via a low-cost template method. By using calcium cyanamide (CaCN2) with cyano groups as a surface adjustment operator and template, the hydrophilic groups are grafted on the surface of carbon nitride. As a result, the optimized hydrogen evolution rate of macropore carbon nitride (MCN) is 4.4 times higher than that of bulk graphitic carbon nitride. The enhanced photocatalytic performance can be attributed to the formation of hydrophilic groups on the surface and the microstructural properties. This work pioneered an idea of using a promising and eco-friendly template method to tailor surface properties of carbon nitride by terminal functional groups.