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用原位红外光谱考察了Rh Mn Li Fe/SiO2 和Rh/SiO2 催化剂表面上CO的吸附态及CO加氢反应过程中吸附物种的变化 .结果表明 ,CO在Rh/SiO2 催化剂上仅有线式吸附态存在 ,而CO在Rh Mn Li Fe/SiO2 催化剂上既有线式吸附态存在 ,又有孪生吸附态存在 .这说明Rh Mn Li Fe/SiO2 催化剂中Rh的分散度较高 .经CO加氢反应 (3 0MPa ,5 93K)后 ,在Rh Mn Li Fe/SiO2 催化剂上可观测到C2 含氧化物前驱物种的吸收谱带 ,而在Rh/SiO2 催化剂上未观测到相应的谱带 ;CO在这两种催化剂上主要以线式吸附态存在 ,孪生吸附态基本消失 .结合催化剂对CO加氢的催化性能 ,可以认为线式吸附的CO对生成C2 含氧化物有贡献 .Rh Mn Li Fe/SiO2 催化剂的高活性是由于助剂的存在削弱了其表面吸附CO的C O键 ,促进了CO的活化 ,从而有利于C2 含氧化物前驱物的生成
In situ FT-IR spectroscopy was used to investigate the adsorption states of CO on the surface of Rh-Mn Li Fe / SiO2 and Rh / SiO2 catalysts and the change of adsorption species during the CO hydrogenation reaction. The results showed that CO was only adsorbed linearly on Rh / SiO2 catalyst State, while the presence of CO on the Rh Mn Li Fe / SiO2 catalyst both existing linear state and twins adsorption state.This shows that Rh Mn Li Fe / SiO2 Rh dispersion in the higher catalyst by the CO hydrogenation reaction (3 0MPa, 5 93K), the absorption band of precursor species of C2 oxide was observed on Rh Mn Li Fe / SiO2 catalyst, while the corresponding band was not observed on Rh / SiO2 catalyst; The two catalysts mainly exist in the linear adsorption state and the twin adsorption states disappear basically.With the catalytic activity of the catalysts for the hydrogenation of CO, it can be considered that the linear adsorption of CO contributes to the formation of C2 oxides.Rh Mn Li Fe / SiO2 The high activity of the catalyst is due to the presence of additives to weaken the adsorption of CO CO bonds on their surface, and promote the activation of CO, which is conducive to C2 oxide precursor generation