浸渍/共沉淀法对BaO改性单Pd催化剂净化甲醇汽油车尾气性能的影响(英文)  

Ba O Modified Pd-Based Catalysts:Synthesis by Impregnation/Co-Precipitation and Application in Gasoline-Methanol Exhaust Purification

作　　者：张雪乔[1,2] 田浩杞 叶芝祥[1] 陈耀强[2] 

机构地区：[1]成都信息工程学院资源环境学院,成都610225 [2]四川大学催化材料科学研究所,成都610064

出　　处：《无机化学学报》2015年第1期166-176,共11页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.51408076,11405113);四川省教育厅重点科研基金(No.14ZA0163);成都信息工程学院科研人才基金(No.J201416)资助项目

摘　　要：采用浸渍和共沉淀两种方法分别制备了Ba O改性的Pd/CeO2-ZrO2-La2O3-Al2O3催化剂。运用N2吸附-脱附,X射线衍射(XRD),H2程序升温还原(H2-TPR),NH3程序升温脱附(NH3-TPD),透射电子显微镜(TEM)和X射线光电子能谱(XPS)对催化剂进行表征,并考察其对甲醇,CO,C3H8和NO的催化性能。活性测试结果表明,Ba O的引入可明显改善Pd催化剂对甲醇,CO,C3H8和NO的催化活性,且浸渍法最佳,起燃温度(T50)分别降低了43,31,45和35℃。XRD,H2-TPR及XPS结果表明,浸渍法引入Ba O主要通过表面改性方式,强化Pd-Ce界面间的相互作用,改善催化剂的还原性能,进而提高催化剂的低温活性;而共沉淀法则是通过结构改性方式增加CeO2晶格缺陷,加速活性氧物种的流动,Ce3+浓度的增加是促使CO氧化活性显著提高的主要原因。Barium oxide was developed to modify palladium catalysts supported on CeO2-ZrO2-La2O3-Al2O3（CZLA）compound oxides by impregnation/co-precipitation methods.Low temperature N2adsorption-desorption,X-ray diffraction（XRD）,H2-temperature-programmed reduction（H2-TPR）,NH3-temperature programmed desorption（NH3-TPD）,transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS） were employed to characterize the influence of the preparation method on physicochemical properties of the catalyst.Catalytic activity per-formance for methanol,CO,C3H8 and NO conversion was evaluated.Catalytic activity results show that the addition of Ba O has a positive effect on the conversion of all pollutants,and the best results are achieved by the impregnation method.The light-off temperature decreases by 43,31,45 and 35 ℃,respectively.The XRD,H2-TPR and XPS results confirm that the impregnation method is mainly based on the surface modification.The enrichment of Ba2 ＋strengthens the Pd-Ce interaction in Pd-Ce interface,promoting the reductive ability,thus increasing the catalytic activity at low temperature.The co-precipitation method results in structure disorder and additional anion vacancies accompanied by the formation of more Ce^3＋,which may be beneficial to the conversion of CO.

关 键 词：氧化钡 钯 铈 甲醇 催化转化 

分 类 号：O643.361[理学—物理化学] O643.31[理学—化学]