Selective oxygen addition to adsorbed CH2 and CH3 on Pd(100)

被引:20
|
作者
Solymosi, F [1 ]
Kovacs, I [1 ]
Revesz, K [1 ]
机构
[1] ATTILA JOZSEF UNIV,INST SOLID STATE & RADIOCHEM,H-6701 SZEGED,HUNGARY
关键词
aldehydes; alkanes; alkenes; catalysis; chemisorption; methyl oxide; methylene iodide; oxidation; palladium; surface chemical reaction; visible and ultraviolet photoelectron spectroscopy; X-ray photoelectron spectroscopy;
D O I
10.1016/0039-6028(96)00010-6
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The reaction pathways of CH2 and CH3 in the presence of coadsorbed oxygen atoms on a Pd(100) surface were investigated by means of temperature-programmed desorption (TPD) and photoelectron spectroscopy (XPS and UPS). The CHx species were produced by the dissociation of CH2I2 and CH3I. Adsorbed oxygen shifts the dissociation temperature of iodo compounds and the temperature of self-hydrogenation of CHx fragments formed at higher temperatures. Oxygen atoms reacted with CH2 above 150 K to give formaldehyde, which desorbed from the surface after its formation. Above 200 K, the oxidalion of CH2 led to the production of H2O and CO, the latter being further oxidized to CO2 above 370 K. The oxidation of CH3 species with oxygen atoms also occurred above 200-220 K to yield CH2O, H2O and CO, very probably through the transient formation of CH3O species.
引用
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页码:121 / 129
页数:9
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