以乙烯和乙炔为探针分子,采用原位红外光谱技术研究了Pd-Ag/Al2O3和Pd/Al2O3催化剂上乙炔加氢反应,通过乙炔吸附,乙炔和氢的共吸附和交替吸附表征了催化剂表面吸附物种的变化.结果表明,在Pd-Ag/Al2O3催化体系中,乙炔在Pd-Ag/Al2O3和Pd/Al2O3催化剂有着不同的吸附性能,另外,加氢反应会导致在催化剂表面形成由长分子链的烷烃组成的碳氢化合物层,该吸附层与绿油有着相似的红外光谱特征,最关键的是乙炔和氢的吸附顺序和碳氢化合物层的生成量之间存在着一定的关系,这将直接影响催化剂的加氢性能.%Using acetylene and ethylene as probe molecule,acetylene hydrogenation on Pd-Ag/Al2O3 and Pd/Al2O3 catalysts were studied by in-situ diffuse reflectance infrared fourier transform spectroscopy（DRIFTS）.Chemisorptions properties of catalysts were characterized by C2H2 adsorption,C2H2 and H2 al-ternate adsorption and co-adsorption.The results showed the different adsorption properties between acety-lene and ethylene over Pd-Ag/Al2O3 or Pd/Al2O3.In addition,hydrogenation of acetylene would create the carbonaceous layer on the catalysts＇ surface,the carbonaceous layer was made up of long-chain alkane which has similar infrared spectra of green oil and has great effect on the selectivity properties of catalyst.There is a correlation between the amount of carbonaceous layer and the adsorption order of acetylene and hydrogen.
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