Preparation and characterization of niobium carbide crystallites

  • Choi, Jeang-Gil (Department of Nano-Bio Chemical Engineering, Hannam University)
  • Published : 2009.06.30


The preparation and characterization of niobium carbide crystallites were investigated in this study, and in particular, the effect of preparation conditions were studied on the synthesis of niobium carbides crystallites. For this purpose, various characterization techniques including x-ray diffraction, BET surface area, and oxygen uptake measurements were employed to characterize the synthesized niobium carbide crystallites. The niobium carbide crystallites were prepared using niobium oxide and methane gas or methane-hydrogen mixture. Using x-ray diffraction a lattice parameter of $4.45{\AA}$ and a crystallite size ranging from $52{\AA}$ to $580{\AA}$ was found. BET surface areas ranged from $3.2\;m^2/g$ to $16.6\;m^2/g$ and oxygen uptake values varied from $0.5{\mu}mol/g$ to $6.1{\mu}mol/g$. It was observed that niobium carbide crystallites were active for ammonia decomposition reaction. While the BET surface area increased with increasing the oxygen uptake, the conversion of ammonia decomposition reaction decreased. These results indicated that the ammonia decomposition over these materials was considered to be structure-sensitive.


  1. N.I. I1'chenko, "Oxidative catalysis on transition-metal carbides", Kinetik Kataliz 18(1) (1977) 153
  2. G.V. Samsonov, T.G. Bulankovs, P.A. Khodak, E.M. Prshedromirskaya, V.S. Sinel'nikova and V.M. Sleptsov, "Catalytic properties of carbides and silicides of transition metals in the dehydrogenation of ethyibenzene to styrene", Kinetika Kataliz 10(5) (1969) 1057
  3. J.-G. Choi, R.L. Curl and L.T. Tompson, "Molybdenum nitride catalysts I. Influence of the synthesis factors on structural properties", J. Catal. 146 (1994) 218
  4. B.D. CuIlity, Elements of X-Ray Diffraction 2nd ed. Addison-Wesley Publishing Company, Inc. (1978) chap 10
  5. R.F. Horlock, P.L. Morgan and P.J. Anderson, Trans. Faraday Society 59 (1963) 721
  6. J.-G. Choi, J.R. Brenner and L.T. Tompson, "Pyridine hydrodenitrogenation over molybdenum carbide catalysts", J. Catal. 154 (1995) 33
  7. J.-G. Choi, J. Ha and J.-W. Hong, "Synthesis and catalytic properties of vanadium interstitial compounds", Applied Catal. 168 (1998) 47