Synthesis of high crystalline carbon-nitrogen layered compounds by CVD using nickel and cobalt catalysts

Carbon-nitrogen layered compounds, C(x)Ns, have been synthesized by thermal decomposition (CVD) of acetonitrile and pyridine with nickel or cobalt catalyst at 800-1200 degrees C. Acetonitrile yielded C14N-C62N at 800-1100 degrees C and pyridine gave C25N-C60N containing less nitrogens at 800-1000 degrees C. The nitrogen concentrations were the highest in the products, C14N-C16N prepared from acetonitrile in the temperature range, 850-1000 degrees C. X-ray diffraction patterns indicate that the CxN samples have the same layered structures as usual carbon materials. The use of nickel or cobalt catalyst highly improves the crystallinity of CxN samples, and increases the nitrogen atoms incorporated in graphene layers compared with the pyridine type nitrogens existing at the edge of graphene layers. No distinct difference was found in the compositions and crystallinity of C(x)Ns prepared with two kinds of catalysts, nickel and cobalt. (C) 1997 Elsevier Science Ltd. All rights reserved.