A Rapid Microwave-Assisted Thermolysis Route to Highly Crystalline Carbon Nitrides for Efficient Hydrogen Generation

Highly crystalline graphitic carbon nitride (g-C₃ N₄ ) with decreased structural imperfections benefits from the suppression of electron-hole recombination, which enhances its hydrogen generation activity. However, producing such g-C₃ N₄ materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high-quality g-C₃ N₄ with reduced structural defects by judiciously combining the implementation of melamine-cyanuric acid (MCA) supramolecular aggregates and microwave-assisted thermolysis. The g-C₃ N₄ material produced after optimizing the microwave reaction time can effectively generate H₂ under visible-light irradiation. The highest H₂ evolution rate achieved was 40.5 μmol h^-1 , which is two times higher than that of a g-C₃ N₄ sample prepared by thermal polycondensation of the same supramolecular aggregates in an electric furnace. The microwave-assisted thermolysis strategy is simple, rapid, and robust, thereby providing a promising route for the synthesis of high-efficiency g-C₃ N₄ photocatalysts.