【摘要】 采用共沉淀法制备了Ce0.1+xTi0.5-xA l0.2Y0.1La0.1O1.8(0≤x≤0.4)材料,并对所制备的材料进行了X射线衍射(XRD)和X射线光电子能谱(XPS)的表征,测定了材料的比表面积(BET法)和储氧量(OSC),同时采用氢气程序升温还原(H2-TPR)和氨气程序升温脱附(NH3-TPD)研究了材料的还原性能和表面酸性.研究结果表明,Ce/Ti摩尔比大于1∶2的材料能形成立方萤石结构的固溶体,Ce/Ti摩尔比为1时,材料表面Ce4+/Ce3+摩尔比达到最大;随着Ce/Ti摩尔比的增大,材料的储氧能力先增大后减小,而TPR还原峰温则是先减小后增大,当Ce/Ti摩尔比为1时,材料的储氧量达到最大,为660μmol/g;还原峰峰温最低,为616℃.以制备的材料为载体制备了一系列Pt/Ce0.1+xTi0.5-xA l0.2Y0.1La0.1O1.8三效催化剂,并对催化剂进行了活性评价.活性测试结果表明,以Ce/Ti比为1的载体材料制成的催化剂对C3H8,CO和NO的起燃温度分别为236,147和228℃,表现出了优异的温度特性.更多还原

【Abstract】 Ce0.1+xTi0.5-xAl0.2Y0.1La0.1O1.8(0≤x≤0.4) mixed oxides were prepared by co-precipitation method and characterized by means of X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),nitrogen adsorption(BET),oxygen storage capacity(OSC),H2-temperature programmed reduction(H2-TPR) and NH3-temperature programmed desorption(NH3-TPD).The results of XRD revealed that there was only one single cubic phase in Ce0.1+xTi0.5-xAl0.2Y0.1La0.1O1.8 system when x value increased from 0.2 to 0.4.The results of XPS showed that the ratio of superficial Ce4+/Ce3+ is maximal when x is 0.2.With the increase of Ce/Ti ratio,OSC is increased to a maximum value,and then gradually decreased.When x value is 0.2,the OSC reaches to 660 μmol/g,and the reduction temperature of Ce4+ is the lowest according to the H2-TPR test(616 ℃).In this paper,a series of Pt/Ce0.1+xTi0.5-xAl0.2Y0.1La0.1O1.8 three-way catalysts were prepared and the catalytic activities of catalysts were investigated.The results revealed that Pt/Ce0.3Ti0.3Al0.2Y0.1La0.1O1.8 exhibits excellent low-temperature catalytic activity.The light-off temperature of C3H8,CO and NO over Pt/Ce0.3Ti0.3Al0.2Y0.1La0.1O1.8 is 236,147 and 228 ℃,respectively.更多还原