Stepwise dehydrogenation of NH3 at the Ru(1120) surface

The thermal dehydrogenation of NH3 was studied on Ru(11 (2) over bar0) using high-resolution electron energy-loss spectroscopy and thermal desorption spectroscopy. Following NH3 exposure at 85 K, the expected three dehydrogenation steps could be separated, allowing to isolate successively NH2, NH and N on the surface. The R U(1 1 (2) over bar 0) Surface is highly reactive as indicated by the complete dehydrogenation of NH3 for exposures up to 0.2 L. During annealing to 300 K both the channels for desorption and dehydrogenation are opened. Following adsorption at 85 K, the obtained nitrogen coverage of 0.11 ML is low, while for dissociative adsorption of NH3 at 300 K, a maximum coverage of 0.38 ML is achieved, and the stability of NH2 is increased. (C) 2002 Elsevier Science B.V. All rights reserved.