Kulkarni, GU and Rao, CNR and Roberts, MW (1995) Nature of the Oxygen Species at Ni(110) and Ni(100) Surfaces Revealed by Exposure to Oxygen and Oxygen-Ammonia Mixtures: Evidence for the Surface Reactivity of O- Type Species. In: Journal of Physical Chemistry, 99 (10). pp. 3310-3316.
PDF
Nature_of_the_Oxygen_Species.pdf - Published Version Restricted to Registered users only Download (735kB) | Request a copy |
Abstract
Adsorption of dioxygen at clean Ni(110) and Ni(100) surfaces gives rise to two prominent features in the O(1s) spectra at 530 and 531 eV due to O2- and O- type species, respectively. Interaction of ammonia with a Ni(100)-O surface where theta(oxygen) < 0.1 ML favors the dissociation of NH3 giving NHn, (n = 1, 2) and N(a) species. This is accompanied by a decrease in the intensity of the 531 eV feature. On the other hand. a Ni(100)-O surface where the oxygen species are mainly of the O2- type is unreactive, Coadsorption studies of NH3-O-2 mixtures show that at Ni(110) surfaces the uptake of both oxygen and ammonia increase with the proportion of oxygen in the NH3-O-2 mixture. The surface concentrations of the O- species and the NHn species also increase with the increase in the O-2/NH3 ratio while the slope of the plot of sigma(N) versus sigma(O-) is around unity. The results demonstrate the high surface reactivity of the O- species and its role in the dissociation of ammonia. Based on these observations, the possibility of the formation of a surface complex between ammonia and oxygen (specifically O-) is suggested. Results from vibrational spectroscopic studies of the coadsorption of NH3-O-2 mixtures are consistent with those from core-level spectroscopic studies.
Item Type: | Journal Article |
---|---|
Publication: | Journal of Physical Chemistry |
Publisher: | American Chemical Society |
Additional Information: | Copyright of this article belongs to American Chemical Society. |
Department/Centre: | Division of Physical & Mathematical Sciences > Centre for High Energy Physics |
Date Deposited: | 02 Jun 2011 05:04 |
Last Modified: | 28 Nov 2018 15:15 |
URI: | http://eprints.iisc.ac.in/id/eprint/38124 |
Actions (login required)
View Item |