中文摘要：

采用浸渍法制备了Nb改性的Pd／Al2O3催化剂，考察了该催化剂催化苯燃烧反应性能，并研究了催化剂的稳定性．结果表明，Nb的添加明显提高了Pd／Al2O3催化剂性能，在195℃时苯转化率达到90％，苯的完全燃烧温度降低了40℃．采用X射线衍射（XRD）、X射线光电子能谱（XPS）、透射电子显微镜（TEM）、H2程序升温还原（H2-TPR）、NH，程序升温脱附（NH2-TPD）和氮气吸附等手段对催化剂进行了表征，结果表明，Nb的加入不仅提高了Pd物种的分散度，同时改变了部分Pd的价态，形成适宜反应的PdO—Pd物种，并促进了催化剂表面氧浓度的增加，使氧物种氧化能力增强，从而提高了催化性能．1％Pd-5％Nb／Al2O3催化剂的催化活性高于2．0％Pd／Al2O3催化剂．

英文摘要：

Pd/Al2O3 catalyst modified by Nb promoter was prepared and tested for benzene catalytic combus- tion. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, temperature- programmed desorption of NH3, Hz temperature-programmed reduction, and N2 adsorption. The results showed that the addition of Nb effectively improved the activity and stability of Pd/Al2O3 catalyst by increasing the dis- persion of Pd active components, changing the oxidation state of partial palladium and increasing oxygen spe- cies concentration on the surface of catalyst. In case of Pd-Nb/Al2O3 catalyst, the benzene conversion of 90% was obtained at temperature as low as 195 ℃. Moreover, the 1% Pd-5% Nb/Al2O3 catalyst was more active than the 2% Pd/Al2O3 catalyst. It is concluded that Pd and Nb have a synergistic effect in benzene catalytic combustion.