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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。
Ba O-modified Pd / CeO2-ZrO2-La2O3-Al2O3 catalysts were prepared by impregnation and coprecipitation. The effects of N2 adsorption-desorption, XRD, H2-TPR, NH3-TPD, TEM and XPS were investigated. The catalyst was characterized and its catalytic performance for methanol, CO, C3H8 and NO was investigated. The results of the activity test show that the introduction of BaO can obviously improve the catalytic activity of Pd catalyst for methanol, CO, C3H8 and NO, and the impregnation method is the best, the light-off temperature (T50) decreased by 41, 41, 45 and 35 ℃ respectively. The results of XRD, H2-TPR and XPS show that Ba O introduced by impregnation method mainly improves the interfacial interaction of Pd-Ce by surface modification and improves the reduction performance of the catalyst, thereby increasing the low-temperature activity of the catalyst. The coprecipitation method Through the structural modification of CeO2 lattice defects, accelerating the flow of reactive oxygen species, Ce3 + concentration is the main reason to promote CO oxidation activity significantly increased.