3724a. WINTER, E. [Catalytic Decomposition of Ammonia Over Iron.] Ztschr. physik. Chem., vol. 13, Abt. B, 1931, pp. 401-424; Chem. Abs., vol. 26, 1932, p. 364.
Catalytic decomposition of NH3 in NH3-H2 or NH3-H2-N2 mixtures was studied over Fe catalysts at 500°-700° by a flow system. On supported Fe catalysts the rate of decomposition was approximately proportional to the partial pressure of NH3 and inversely proportional to the 3/2 power of the partial pressure of H2. H2 was without effect on the decomposition. One series of runs over a roll of Fe gauze indicated that the rate of decomposition was proportional to the first power of NH2 partial pressure and inversely to the first power of H2. The energy of activation over the temperature range studied is about 51,000-54,000 cal. The relation between catalytic activity and formation of Fe nitride is discussed. The results indicate that the reaction rate depends upon the concentration of atomic N on the surface of the catalyst.