Rh（100表面乙醇吸附与分解的HREELS研究

利用热脱附谱和高分辨能量损失谱技术研究了乙醇在Ｒｈ（１００）表面的吸会和分解过程，结果表明，１３０时Ｒｈ（１００）面暴露乙醇，表面首先形成化学附层，随乙醇暴露增加，表面出现多层凝聚态，表面升温至１５０Ｋ，吸附乙醇从Ｒｈ（１００）表面脱附，同时部分化学吸附乙醇分子发生羟基断裂，生成表面乙氧基，进一步升谩，表面乙氧基脱氢分解，其分解的主要途径是发生甲基脱氧，β－Ｃ与表面发生作用，生成一种含氧的金属有机

HREELS Studies of Ethanol Adsorption and Decomposition on Rh(100) Surface

The adsorption and decomposition of ethanol on the clean Rh (100) surface werestudied using thermal desorption spectroscopy(TDS) and high resolution electron energy lossspectroscopy (HREELS). At 130 K, on Rh (100) surface, the adsorption started from achemisorbed ethanol structure which was bonded to the surface through both O and H moi-eties, with the O-H bond almost parallel to the surfaces. Additional condensed phase of ad-sorbed ethanol was found to exist through hydrogen bonding. At about 150 K, the multilay-er-adsorbed ethanol desorbed from the surfaces, while the remaining chemisorbed ethanolcompletely converted to an ethoxy species via the first decomposition step in which O-Hbond scission occurred. The small amount of methane formed indicated that the dehydro-genation of the ethoxide intermediates on the clean Rh(100) surface was non-selective. Lossof hydrogen from the methylene group would result in the formation of an aldehyde interme-diate. Decarbonylation of the aldehyde intermediates produced methane and CO. This path-way appeared to be a minor one for ethoxide decomposition on Rh(100). The main ethoxidedehydrogenation proceeded via the cleavage of a C-H bond on the methyl group, resultingin the formation of an oxametallocyclic intermediate. The loss spectra at ~629 cm-1 is as-signed to this intermediate. The C-C bond scission occurred at the same time in the oxamet-allocyclic dehydrogenation sequence. Then the CO and hydrocarbon moieties were formed onthe surface.