A series of CexZr0.50-xAl0.50O1.75(0.05≤x≤0.45) mixed oxides with different Ce/Zr ratio were prepared by co-precipitation method and characterized by means of X-ray diffraction(XRD),Brunauer-Emmet Teller method(BET),temperature-programmed reduction(H2-TPR) and oxygen pulsing technique.The XRD results showed that all samples kept the single CeO2 cubic fluorite structure after calcination at 600 and 1000 oC for 5 h.The results of BET revealed that CexZr0.50-xAl0.50O1.75 with Ce/Zr molar ratio 1/1 exhibited hi...
Pd/YZ-Al2O3 （Y and Zr modified Al2O3, and hereafter, labelled as A1） catalysts with 4 wt% additive CeO2 and/or La2O3 were prepared and characterized by X-ray photoelectron spectroscopy （XPS）, NO-temperature programmed desorption （NO-TPD）, Nz-adsorption/desorption （Branauer-Emmet-Teller BET method）, X-ray diffraction （XRD） and CO-chemisorption. Catalytic activities for CH4, CO and NO conversion were tested in a gas mixture simulated the emissions from natural gas vehicles （NGVs） operated under stoichiometric conditions. The results indicated that all catalysts exhibited excellent catalytic performances for CH4 and CO oxidation and the promoting effect of CeO2 or La2O3 was significant for NO conversion. XPS results showed that the electron density around Pd was increased by CeO2 and/or La2O3, the binding energy of Pd 3d decreased as the order： Pd/Al 〉 Pd/Ce/Al 〉 Pd/La/Al 〉 Pd/CeLa/Al. The electron-rich Pd showed Rh-like catalytic properties which exhibited good activity for the reduction of NO. NO-TPD results showed that the addition of CeO2 and/or La2O3 increased NO adsorption on surface, and promoted the conversion of NO.
Yile Li Xiaoyu Zhang Enyan Long Hongmei Li Dongdong Wu Li Cai Maochu Gong Yaoqiang Chen
Complete oxidation of benzene over supported manganese oxides catalysts was studied.Composite supports Ce0.5＋xZr0.4–xLa0.1O1.95-Al2O3 （x=0,0.1,0.2,0.3,0.4）,and CeO2-Al2O3 were prepared by co-precipitation method,and manganese oxides （MnOx） catalysts were prepared by incipient wetness method.Catalytic activity was performed in a conventional fixed bed flow reactor.Among these catalysts,MnOx supported on Ce0.8Zr0.1La0.1O1.95-Al2O3 was found to have the highest catalytic activity for benzene oxidation.The complete conversion temperature of benzene on MnOx/Ce0.8Zr0.1La0.1O1.95-Al2O3 was 328 oC.The catalysts were characterized by X-ray diffraction （XRD）,Brunauer-Emmett-Teller （BET） specific surface area,X-ray photoelectron spectra （XPS） and H2-temperature programmed reduction （H2-TPR）.The results of BET and XRD measurements indicated that the addition of ZrO2 improved the textural properties.XPS measurements showed that MnOx was composed of MnO2 and Mn2O3.The catalysts reported in this work have significant potential in industrial application for their high performance and low cost.
