(CeO_2)_x(La-Al_2O_3)_(1-x)复合氧化物对柴油车尾气中可溶性有机成分的催化氧化(英文)

Catalytic Oxidation of Soluble Organic Fraction in Diesel Exhausts Using Composite Oxides (CeO_2 )_x (La-Al_2O_3 )_(1-x)

采用共沉淀法制备了一系列(CeO2)x(La-Al2O3)1-x复合氧化物(其中x为质量分数,x=0.00,0.25,0.50,0.75,1.00),以其为催化剂.采用热重-差热分析(TG-DTA)法模拟测试该系列催化剂对柴油车尾气中可溶性有机成分(SOF)的催化氧化性能.结果表明,当x=0.75时,催化剂活性最高,可使SOF在125°C起燃,355°C完全转化.并用低温N2吸附-脱附,储氧量(OSC)测试,X射线衍射(XRD),X射线光电子能谱(XPS)和H2程序升温还原(H2-TPR)等手段对催化剂进行了表征.研究结果表明,适量La和Al共掺杂增大了氧化铈的比表面积和催化剂中Ce3+所占的比例,从而提高了催化剂对SOF的低温吸附能力和催化剂的储释放氧能力,因而提高了催化剂对SOF的氧化活性.所制备的(CeO2)0.75(La-Al2O3)0.25复合氧化物适合应用到柴油车尾气净化催化剂中.

A series of catalytic composite oxides （CeO2）x-（La-AI203）1-x （with mass fractions x=0.00, 0.25, 0.50, 0.75, 1.00） was prepared using a co-precipitation method. Thermogravimetric-differential thermal analysis （TG-DTA） was used to determine the performances of these composite oxides in the catalytic oxidation of the soluble organic fraction （SOF） of diesel exhaust. The results show that the catalyst with the highest activity, i.e., x=0.75, enabled the SOF to light-off at 125 ℃ and completely converted the SOF at 355 ℃. The catalysts were characterized using low-temperature N2 absorption-desorption, oxygen-storage capacity （OSC） measurements, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, and H2 temperature-programmed reduction （H2-TPR）. The results indicate that co-doping appropriate amounts of La and AI into the catalyst increases the specific surface area of the cerium oxide and the proportion of Ce^3＋in the catalyst. This may improve the catalyst＇s enhancing its activity in SOF oxidation. These catalysts for diesel oxidation. adsorption abilities at low temperature and its OSC, （CeO2）0.75（La-AI203）0.25 composite oxides are promising