Adsorption and Reaction of NO on Oxidized and Reduced SrTiO{sub 3} (100) Surfaces
Adsorption and reaction of NO on oxidized and reduced SrTiO{sub 3}(100) surfaces have been studied using temperature programmed desorption (TPD). Major desorption peaks for NO from the fully oxidized surface as found at 140 and 260 K, along with a long tail that continues up to 500 K. The desorption features at 140 and 260 K correspond to activation energies of 36 and 66 kJ/mol, respectively, using a simple Redhead analysis. NO reacts non-dissociatively on the fully oxidized surface. Reactivity of reduced SrTiO{sub 3}(100) is relatively higher than that of the fully oxidized surface and is influenced by the adsorption temperature of the NO molecules on the surface. NO and N{sub 2}O are the major desorption products following adsorption of NO on the reduced surface at 110 K. Desorption of N{sub 2}O from significantly reduced SrTiO{sub 3}(100) indicates that the oxygen atoms of the adsorbed NO molecules are preferentially extracted by the surface oxygen vacancy sites whereas the surface oxidizes as a result of the de-oxygenation of the adsorbates. Adsorption of NO on the reduced surface at 297 K is followed by breakage of the N-O bond producing adsorbed N and O atoms and recombination of these ad-species results in desorption of NO and N{sub 2} from this surface. Adsorption of NO on the significantly reduced surface at 200 K is followed by desorption of NO, N{sub 2} and N{sub 2}O as TPD products and the reactivity of this surface at 200 K presumable is a composite of the behavior observed for NO adsorption at 110 and 297 K.
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 15008748
- Report Number(s):
- PNNL-SA-37906; KC0302010; TRN: US200426%%888
- Journal Information:
- Journal of Vacuum Science and Technology, A: Vacuum, Surfaces and Films, Vol. 21, Issue 4; Other Information: PBD: 1 Jul 2003
- Country of Publication:
- United States
- Language:
- English
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