The rate of NH3 decomposition has been measured over the K-Ru/C catalyst, the studies being accompanied by the N-2-TPD experiment. The catalyst proved to be extraordinarily active in ammonia decomposition. The TOF values over K-Ru/C were almost 10(3) times higher than those for the triply promoted magnetite. both referred to the nitrogen chemisorption. The rate of nitrogen desorption was found to be significantly lower than the rate of NH3 decomposition under the comparable conditions. It is suggested that the adsorbate-adsorbate interaction is responsible for the higher rate of the latter. The modelling based on the Langmuir-Hinshelwood kinetics shows the coverage of N-ad in high pressure NH3 synthesis to be very small. (C) 3001 Elsevier Science B.V. All rights reserved.