表面活性剂对CeZrYO储氧材料性能的影响

Influence of Surfactant on Performance of CeZrYO Oxygen Storage Material

采用表面活性剂聚乙二醇改性共沉淀法制备了铈锆钇储氧材料,并详细考察了表面活性剂的添加方式和添加量对储氧材料性能的影响.采用X射线衍射、氧脉冲吸附、H2程序升温还原和N2吸附技术对储氧材料的晶体结构、储氧性能、还原性能和织构性能进行了表征.结果表明,表面活性剂的添加方式和添加量对储氧材料的性能有重要影响.随着表面活性剂添加量的增加,储氧材料的储氧量先增加后减少,在添加量为50%时达最大值.在表面活性剂添加量相同的情况下,与一次性添加制得的样品相比,分两次添加制得的样品的比表面积和孔体积有所增大,抗老化性能有所提高.一次性添加表面活性剂制得的样品经高温老化后,小于10nm的孔基本消失;而分两次添加表面活性剂制得的样品经高温老化后,仍保持有这些小孔.

A CeO2-ZrO2-Y2O3 oxygen storage material was prepared by a surfactant polyethylene glycol-modified coprecipitation method. The influence of the surfactant amount and addition manner on the performance of the oxygen storage material was investigated in detail. The crystal structure, oxygen storage capacity （OSC）, reduction performance, and textural properties of the material were characterized using X-ray diffraction, oxygen pulse adsorption, H2 temperature-programmed reduction, and N2 adsorption. The surfactant amount and addition manner significantly influenced the performance of the oxygen storage material. With the increase of the surfactant amount, the OSC of the material first increased and then decreased, and reached the highest value when the surfactant amount was 50 %. Compared with the material prepared by adding all the surfactant before the precipitation step, the material prepared by adding the surfactant in twice （before the precipitation step and before the dryness step） had larger specific surface area and pore volume and better anti-high temperature aging. When the surfactant was added by once, the material lost the pores smaller than 10 nm after calcination at 1 000 ℃ , but when the surfactant was added in twice, the material still maintained these pores after calcination.