制备条件对介孔纳米铈基储氧材料性能的影响
Influence of Different Preparation Conditions on Cerium-based Oxygen Storage Material
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摘要: 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 N 2 吸附 - 脱附、H 2 - 程序升温还原( H 2 - T P R ) 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 5~1 0m L / m i n 时, 材料的比表面积和孔容最大, 分别为 1 9 0m2 /g 、 0. 4 2m L /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 .Abstract: 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 5~10 mL/min, and the specific surface areas and pore volume were 190 m2/g and 0.42 mL/g, respectively. In addition, the sample calcined in hydrogen-nitrogen gas mixture showed higher redox properties by improving the diffusion rate of bulk oxygen
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