制备方法对Ce_(0.5)Zr_(0.5)O_2固溶体微观晶相结构及还原性能影响的研究

Microstructure and Reducibility of Ce_(0.5)Zr_(0.5)O_2 Solid Solutions Prepared by Different Routes

采用不同合成方法制备了4种组成为Ce0.5Zr0.5O2的铈锆固溶体。通过XRD,BET,H2-TPR,HREM以及SEAD等表征手段,研究了微观晶相结构对铈锆固溶体还原性能的影响规律,以及对固溶体储放氧能力的影响。分析结果表明,在同一组成下,不同制备方法得到截然不同的晶相组成,4种固溶体包含4种不同的晶相组合。通过对微观晶相结构的定量分析,发现立方相的形成对促进固溶体的还原性能起到重要作用。其中,反相微乳法制得的铈锆固溶体能够形成完整的立方相结构,在H2-TPR还原过程中耗氢量最大,表明其具有优良的可还原性及储放氧能力,适合作为TWC,POX等催化剂载体。

A series of Ce0.5Zr0.5O2 sohd solutions were prepared by four different routes. The texture, microstructure and reducibility of the as-prepared solid solutions were examined by means of BET, XRD, HREM, SEAD and H2-TPR. The results showed that different microstructure and texture properties could be achieved by using different synthesis method even for the same compositions. The cubic phase was proved to be the key factor of the enhancement of the reducibility of the Ce0.5 Zr0.5O2 solid solution. Among the four samples, the one prepared by reverse microemulsion method showed a perfect cubic phase and the most reducible property.