制备条件对介孔纳米铈基储氧材料性能的影响

采用共沉淀法制备了铈基储氧材料,考察了滴定速率对该材料织构参数的影响.此外,分别将样品置于空气和氮氢混合气氛围中焙烧,考察了焙烧气氛对该材料氧化还原性能的影响.采用低温N2吸附-脱附、H2-程序升温还原(H2-TPR)及氧脉冲吸附法对材料进行了表征.结果表明,共沉淀法可以制备出结构稳定的纳米铈基材料,当盐溶液滴定速率在5~10 mL/min时,材料的比表面积和孔容最大,分别为190 m2/g、0.42mL/g;此外,在氮氢混合气氛中处理过后能大幅度提高体相氧的扩散速率,从而提高其氧化还原性能.

Influence of Different Preparation Conditions on Cerium-based Oxygen Storage Material

The ceria-based materials were prepared by coprecipitation,and the influence of titration rate on textural properties was investigated.Additionally,the materials were calcined in air and hydrogen-nitrogen gas mixture,respectively,and the influence of calcination conditions on the redox performance of ceria-based oxygen storage materials was investigated.The materials were characterized by low temperature nitrogen adsorption-desorption,H2-temperature programmed reduction(H2-TPR)and oxygen storage capacity(OSC).The results indicated that the ceria-based materials prepared by coprecipitation were formed as stable nanostructure.The sample exhibited the best textrual properties when the titrational rate was 5~10mL/min,and the specific surface areas and pore volume were 190m2/g and 0.42mL/g,respectively.In addition,the sample calcined in hydrogen-nitrogen gas mixture showed higher redox properties by improving the diffusion rate of bulk oxygen.