Study Of Pyrolyzing Melamine To Prepare Carbon Nitride Precursors

In this paper, a turbostratic CN precursor was prepared by means of pyrolysis of melamine, then it was treated by high temperature and high pressure. The pyrolysis process of melamine, mechanism of hydrogen elimination and the effect of catalysts on pyrolysis of melamine were studied. The crystal structures, bonding states and chemical compositions of CN precursor obtained by pyrolyzing melamine are analyzed by X ray diffraction (XRD), burning spectrum, scanning elecron microscope (SEM) and Fourier transform infrared Spectroscopy (FTIR). The results show that the melamine is decomposed at 300~700 ℃ and gives out NH3. The turbostratic CN powder, which contains 36.70 at%C, 47.11 at%N and 16.19 at%H, were prepared by repeated pyrolysis of melamine. When content of hydrogen in pyrolysate reduce to 16 at%, the content of hydrogen decreases no longer with farther pyrolysis of melamine. But the layer structure in pyrolysate became well-ordered with increasing the number of cycle pyrolyzing melamine. Storing H alloy and nickel catalyst contribute to pyrolysis of melamine. Their effect on eliminating hydrogen from melamie is small. The experimental results of high pressure and temperature of pyrolysate show that, a kind of the high pressure product with turbostratic structure was obtained. It's content is 64.13 at%C,35.87 at%N.