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The adsorption and decomposition of CH3NH2 have been studied on Pt(111), Rh(111), and on polycrystalline wires with characterization by TPD, XPS, AES, and steady-state reactivity measurements. HCN, C2N2, and H2 are the exclusive products on Pt while ∼ 15 % N2 is produced on Rh. The dominant surface species on the surface upon heating CH3NH2 is therefore CN which is stable to 1100K on Pt and to 800K on Rh. On an electrically heated Pt wire in a 1 torr reactor, this reaction exhibits self-sustaining rate oscillations over a wide range of temperatures and reactant pressures. These oscillations are quite reproducible with frequencies up to 8 Hz and temperature amplitudes up to 400K. A model incorporating all known rate parameters from low pressure experiments has been shown to fit the observed data semiquantitatively assuming a simple unimolecular reaction which is blocked by adsorbed CN at low temperatures.
