中文摘要：

考察了一系列在不同温度下制备的Cu/Al2O3催化剂对苯催化燃烧的性能，并利用X-射线粉末衍射（XRD）、X-射线光电子能谱（XPS）、程序升温还原（TPR）对催化剂进行了表征．结果表明：低于单层分散的CuO具有可在低温还原的特性．在低于单层分散阈值的范围内，随着CuO负载量的增加催化剂活性加．超过单层分散阈值，催化剂活性反而下降．单层分散的CuO物种是非稳态的．随着焙烧温度的增加，分散阈值也会发生增加，这可能是Cu物种扩散至载体晶相引起的，在这种中情况下，催化剂活性下降．

英文摘要：

The surface dispersion behavior of a series of Cu/γ-Al2O3 catalysts calcined at 300,450 and 600 ℃ were investigated. The dispersion status of copper species obtained from surface and bulk characterization, studied by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and temperature-programmed reduction （TPR） , has been correlated with benzene oxidation activity of the catalysts. The results indicated that copper oxide present in a monolayer dispersed state below the dispersion loading threshold, which could be reduced at lower temperature. The remarkable increase of activity was observed over Cu/γ-Al2O3 catalyst when higher copper loading was imputed even total copper amount was less than threshold. Further increase of copper loading （ higher than threshold） resulted in comparatively lower activity. The monolayer dispersed phase was thermodynamically unstable. Dispersion threshold increased with increasing calcination temperature because copper ions diffused into the support, which led to lower catalytic activity for benzene oxidation.