Solvothermal synthesis of crystalline carbon nitrides

A solvothermal reaction of anhydrous C₃N₃Cl ₃ and Li₃N using benzene as the solvent has been carried out to prepare crystalline carbon nitrides successfully at 350°C and 5-6 MPa. X-ray diffraction (XRD) indicated that the major part of our brown sample was mainly composed of α-C₃N₄ and β-C ₃N₄ with lattice parameters of a = 0.65 nm, c = 0.47 nm for α-C₃N₄ and a = 0.644 nm, c = 0.246 nm for β-C₃N₄, which match the latest ab-initio calculations quite well. The N/C ratio in the powder is about 0.66. The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses suggested the presence of both single and double carbon-nitrogen bonds. The kinetics effects of our solvothermal reaction to prepare crystalline carbon nitrides are also discussed chiefly.