Dissolution of g-C3N4 Using Zinc Chloride Molten Salt Hydrates for Nanobelt Fabrication and Photocatalytic H2O2 Production.

Graphitic-carbon nitride (g-CN), a metal-free two-dimensional layered semiconductor material, holds great potential for energy conversion, environmental remediation, and sensing. However, the limited solubility of g-CN in conventional solvents hinders its widespread application. Improving the dissolution of g-CN in the liquid phase is highly desired but challenging. Herein, we report an innovative approach to dissolve g-CN using ZnCl molten salt hydrates. The solubility of g-CN in the solution reaches up to 200 mg mL. Density functional theory (DFT) results suggest that ZnClHO is the key species that leads to charge redistribution on g-CN surface and promotes the dissolution of carbon nitride in the solution. Furthermore, through dilution, the dissolved carbon nitride can be effectively recovered while maintaining its intrinsic chemical structure. The resultant regenerated CN (r-CN) exhibits nanobelt morphology and demonstrates a substantially improved photocatalytic activity in HO production. The rate of HO production over the r-CN reaches 20,228 μmol g h, which is 6.2 times higher than that of pristine g-CN. This green and efficient dissolution route of g-CN offers an effective approach for its diverse applications.