Laser pyrolysis of carbon-nitrogen gas-phase compounds: An attempted approach to carbon nitride formation

We describe the possibility to synthesize carbon nitride fine powder by laser pyrolysis of acetylene/nitrous oxide/ammonia mixtures. The powders were produced in a flow reactor by varying the relative concentrations of the sensitizers (SF₆/C₂H₄). The kinetics of the reaction was monitored by IR spectrophotometry of the exhaust gases. The powder crystallinity and bond structure was studied by X-ray diffraction (XRD) and IR transmission spectrometry, respectively. The majority of XRD data suggests the presence of the predicted α- and β-C₃N₄ structures, with a concentration depending on starting conditions. The presence of C N bonded phases seems relevant. Under the present conditions, the slight contamination of powders by SF₆ decomposition products could not be avoided.