自模板法制备高热稳定铈锆固溶体

Preparation of Highly Thermally Stable Ceria Zirconia Solid Solutions by Self Template Method

为解决纳米铈锆固溶体高温易烧结、合成过程添加大量表面活性剂、制备步骤繁琐等问题,开发了一种自模板法、不需添加表面活性剂,且操作简单易行的制备高热稳定铈锆固溶体的方法。通过该方法,制备了不同碳酸铵浓度刻蚀得到的铈锆固溶体,并通过XRD、HRTEM、ICP-OES、XPS、N_(2)吸附脱附测试等表征手段来确认刻蚀步骤对所得铈锆固溶体的影响。结果表明,碳酸铵能选择性地将Ce和Zr的氢氧化物沉淀混合物中的部分Zr刻蚀进溶液中,以此达到在固溶体原位造孔的目的。所得的刻蚀铈锆固溶体在1000℃老化5 h后的比表面积高达30 m^(2)/g,远高于普通共沉淀法制备的具有相同铈锆比的样品,表明碳酸铵刻蚀处理能够提高铈锆固溶体的热稳定性,对高性能铈锆固溶体的可控合成具有较好的指导意义。

In order to solve the problems of high temperature sintering,adding a large amount of surfactants in the syn-thesis process,and cumbersome preparation steps of nano ceria zirconia solid solutions,a self template method without adding surfactants was developed for the preparation of highly thermally stable cerium zirconium solid solutions,which is simple and easy to operate.Through this method,ceria zirconia solid solutions obtained by etching with different ammonium carbonate concentrations were prepared,and the effects of etching step on the obtained ceria zirconia solid solutions were confirmed by characterization methods such as XRD,HRTEM,ICP-OES,XPS,N_(2) adsorption isotherms.The results show that ammonium carbonate can selectively etch a portion of Zr in the hydroxide precipitation mixture of Ce and Zr into the solution,thereby a-chieving the goal of in situ pore formation in the solid solutions.The specific surface area of the etched ceria zirconia solid so-lutions obtained after aging for 5 hours at 1000℃ is more than 30 m^(2)/g,which is much higher than the sample prepared by the common coprecipitation method with the same cerium zirconium ratio.This indicates that ammonium carbonate etching treatment can improve the thermal stability of ceria zirconia solid solutions,and has superior guiding significance for the con-trollable synthesis of ceria zirconia solid solutions with high performance.