Preparation of Copper Nitride (Cu<sub>3</sub>N) Nanoparticles in Long-Chain Alcohols at 130–200 °C and Nitridation Mechanism

In our laboratory, we are studying copper nitride (Cu<sub>3</sub>N) nanoparticles as a novel conductive ink that is stable to oxidation and can be metallized at low temperature. In this study, Cu<sub>3</sub>N nanoparticles prepared via the reaction of copper­(II) acetate monohydrate with ammonia gas in long-chain alcohol solvents were characterized by X-ray diffraction analysis, transmission electron microscopy, Fourier transform infrared spectroscopy, and elemental analysis. In addition, we used thermogravimetry–differential thermal analysis to compare the thermal decomposition properties of the prepared Cu<sub>3</sub>N particles and commercially available Cu<sub>3</sub>N particles. The decomposition temperature of the prepared particles was more than 170 °C lower than that of the commercial particles. We also examined the influences of the reaction temperature and the alkyl chain length of the alcohol solvent on the product distribution of the reaction and the morphology of the particles. Our results indicated that increasing the solvent hydrophobicity and eliminating water from the reaction system by increasing the temperature affected the product distribution. On the basis of an observation of chromatic change of the reaction solvent and an analysis of the byproducts in the alcohol solvent after the reaction, we propose a mechanism for the formation of Cu<sub>3</sub>N.