Coadsorption of nitric oxide and oxygen on the Ag(110) surface

• Published in: Surface science 1999-04, Vol.425 (2-3), p.224-232
• Main Authors: BAO, X, WILD, U, MUHLER, M, PETTINGER, B, SCHLÖGL, R, ERTL, G
• Format: Article
• Language: English
• Subjects: Adsorbed layers and thin films; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Photoemission and photoelectron spectra; Physics; Solid-fluid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/s0039-6028(99)00190-9

The coadsorption of NO and O sub 2 on Ag(110) surface has been studied by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and in situ Raman spectroscopy. The existence of oxygen enhances the adsorption of NO by forming the NOx species, that is, NO sub 2 and NO sub 3 , and the NO in turn as a promoter facilitates the cleavage of the dioxygen bond, forming the surface atomic oxygen species having the same spectral characteristics as those produced using oxygen at high pressure. The oxygen species generated by the interaction is composed of two parts. One is produced directly by the decomposition of surface NO-O sub 2 complex at ca 625 K, which raised an O 1s feature at 530.5 eV and is absent at ca 800 K, while the another with an O 1s binding energy of 529.2 eV emerges at higher temperatures and shows similar properties as the reported gamma -state oxygen which bound tightly on restructured silver surface. The exposure to NO and O sub 2 causes noticeable changes in the morphology of the Ag(110) surface and the flat terraces superseded by small (ca 0.1 mu m) pits, and particles with typical diameters of a few micrometers were formed at elevated temperatures.