TPD, HREELS and UPS study of the adsorption and reaction of methyl nitrite (CH3ONO) on Pt(111) |
| |
Authors: | John W Peck Daniel I Mahon David E Beck Barbara Bansenaur and Bruce E Koel |
| |
Institution: | Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA |
| |
Abstract: | The adsorption and reaction of methyl nitrite (CH3ONO, CD3ONO) on Pt(111) was studied using HREELS, UPS, TPD, AES, and LEED. Adsorption of methyl nitrite on Pt(111) at 105 K forms a chemisorbed monolayer with a coverage of 0.25 ML, a physisorbed second layer with the same coverage that desorbs at 134 K, and a condensed multilayer that desorbs at 117 K. The Pt(111) surface is very reactive towards chemisorbed methyl nitrite; adsorption in the monolayer is completely irreversible. CH3ONO dissociates to form NO and an intermediate which subsequently decomposes to yield CO and H2 at low coverages and methanol for CH3ONO coverages above one-half monolayer. We propose that a methoxy intermediate is formed. At least some C–O bond breaking occurs during decomposition to leave carbon on the surface after TPD. UPS and HREELS show that some methyl nitrite decomposition occurs below 110 K and all of the methyl nitrite in the monolayer is decomposed by 165 K. Intermediates from methyl nitrite decomposition are also relatively unstable on the Pt(111) surface since coadsorbed NO, CO and H are formed below 225 K. |
| |
Keywords: | Auger electron spectroscopy (AES) Chemisorption Low energy electron diffraction (LEED) Low index single crystal surfaces Methylnitrite Platinum Thermal desorption spectroscopy Visible and ultraviolet photoelectron spectroscopy |
本文献已被 ScienceDirect 等数据库收录! |
|