中文摘要：

通过溶胶-凝胶法制备了xMnyCe/γ-Al_2O_3（x∶y为摩尔比,x=4,6,8,10;y=10）催化剂。利用X射线衍射（X-raydiffraction,XRD）和X射线光电子能谱（X-rayphotoelectronspectroscopy,XPS）对催化剂的理化性能进行了表征,并在管式固定床反应器中考察了在不同温度下催化剂对NO的催化氧化活性影响规律。结果表明,NO转化率随着温度的升高而增加,在300℃时达到峰值,随后受热力学控制,NO转化率随温度的升高有所降低。在250~350℃温度区间,xMn10Ce/γ-Al_2O_3（x≥6）催化剂都表现出较好的NO催化氧化活性。其中,6Mn10Ce/γ-Al_2O_3催化剂的低温催化活性较好,在200℃时对NO的转化率达44.8%,300℃时高达83.6%。Mn-Ce/γ-Al_2O_3催化剂的NO氧化性能由强到弱为：6Mn10Ce/γ-Al_2O_3〉8Mn10Ce/γ-Al_2O_3〉10Mn10Ce/γ-Al_2O_3〉4Mn10Ce/γ-Al_2O_3。

英文摘要：

With the aim of studying the effect of Mn-Ce catalysts on the NO oxidation activity,a series of xM nyC e/γ-Al_2O_3（x：y is mole ratio,x=4,6,8,10; y=10） catalysts were synthesized by a sol-gel method.The samples were dried at 110 ℃ for 24 h,calcined in air for 1 h at 300℃ and then for 5 h at 500 ℃ to obtain the required 40-60 mesh powder.The effect of metallic Mn and Ce on their microstructure and catalytic properties were investigated by X-ray Diffraction（XRD） and X-ray Photoelectron Spectroscopy（XPS） analysis.According to the results of analysis,the diffraction peaks of Mn_2O_3 became stronger and then shifted to weaker with the value of x increasing from 4 to 10,while Mn_2O_3 reached up to its peak value when x was 6.The grain size of cerium in the form of CeO_2 was 26 nm as indicated by Scherrer equation.CeO 2 diffraction peak shifted to a higher angle,due to the cell shrinkage caused by the fact that a part of Ce^4＋ ions were replaced by Mn^4＋ and Mn^3＋,which improved the oxygen vacancy concentration and increased the activity of catalyst.The dissymmetric peak of Mn 2p3/2 observed in XPS spectra proved that Mn^3＋ and Mn^4＋ were both present in the xM n10Ce/γ-Al_2O_3 catalyst.MnO_2 could be reducted to Mn O while Mn O would be oxidated to Mn O2 by the lattice oxygen generated by CeO 2.And the peak of O 1s indicated that the content of lattice oxygen of 6Mn10Ce/γ-Al_2O_3 and 8Mn10Ce/γ-Al_2O_3 was different,which was mainly because of the different Mn/Ce ratio.The higher level of O was more favorable to the oxidative of NO.Furthermore,the effects of temperature on the catalytic oxidation activity of NO were investigated based upon a tubular fixed bed reactor in the range of 150-450 ℃ with an inside diameter of 10 mm and plugged between two silica wool layers to prevent the sample being blew away.The gases used in test were 500 ppm NO,10% O2,with N2 in balance and a space velocity of 55 000/h.Results show that NO2 concentration over 6Mn10Ce/γ-Al_2O_3 catalysts reached stable af