ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Adsorption and thermal dehydrogenation of NH3, adsorbed at 80 K on the open Ru(112¯1) surface, was studied using high-resolution electron energy-loss spectroscopy (HREELS) and thermal desorption spectroscopy (TDS). For the NH3 monolayer, a strong dipole-active mode is found at 15 meV which is newly assigned to Tz, the frustrated-translation mode perpendicular to the surface of NH3 bonding with the nitrogen atom to the Ru surface. Increasing the temperature, 70% of NH3 desorbs before a channel for dehydrogenation opens at about 280 K. The remaining 30% decomposes completely during further warming to 470 K. The dehydrogenation of NH3 gives rise to four peaks in the H2 TDS which are assigned to desorption of coadsorbed hydrogen at 220 K and three dehydrogenation reaction steps at 320, 360, and 420 K in accordance with HREELS. The reaction intermediates NH2 and NH are identified through HREELS. In a new interpretation NH2 is characterized by intense modes at 163 meV (rocking) and at 189 meV (scissoring). Using a maximum entropy algorithm six frequencies for ν(Ru–N) were resolved at 46, 50, 58, 61, 69, and 75 meV. © 2001 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1390523
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