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

Highly crystalline graphitic carbon nitride (g-C3N4) with decreased structural imperfections benefits from the suppression of electron–hole recombination, which enhances its hydrogen generation activity. However, producing such g-C3N4 materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high-quality g-C3N4 with reduced structural defects by judiciously combining the implementation of melamine–cyanuric acid (MCA) supramolecular aggregates and microwave-assisted thermolysis. The g-C3N4 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-C3N4 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-C3N4 photocatalysts.