CuO/CeO_2-Al_2O_3催化剂中CuO物种的原位XRD、Raman和TPR表征

Characterization of CuO Species in CuO/CeO_2-Al_2O_3 Catalysts by In-situ XRD, Raman Spectroscopy and TPR

采用原位XRD、激光Raman光谱和TPR(程序升温还原)技术研究了CuO(w,%)/CeO2-Al2O3催化剂中CuO物种的存在形式及其CuO物种的迁移.低温焙烧(300℃)催化剂,CuO以高分散和晶相两种形式存在于CeO2-Al2O3载体表层.随着焙烧温度的升高,CuO开始从表层向CeO2内层迁移.处于内层的CuO部分以晶相形式存在,部分与Al2O3载体反应生成CuAl2O4.高温有利于表层CuO向CeO2内层迁移,同时促进CuAl2O4生成.结果表明结合原位XRD、激光Raman光谱和TPR技术可以有效地观察催化剂中CuO物种的存在形式和分布.

CuO species and thermal solid-solid interaction in CuO（ω,%）/CeO2-Al2O3 catalysts prepared by an impregnation method are characterized by in-situ XRD, Raman spectroscopy and H2-TPR techniques. Experiment results show that CuO presents as highly dispersed and bulk CuO on the surface of CuO（33.3%）/CeO2-Al2O3 calcined at 300℃. At high temperatures CuO can be transferred from the surface into the internal layer of CeO2 and the transference of CuO increases with increasing the calcination temperature. Some of CuO that exists in the internal layer of CeO2 presents as bulk CuO, some of that interacts with the support Al2O3 to produce CuAl2O4. The calcination temperature also promotes the CuO-Al2O3 interaction. It shows that the existence of different CuO species can be effectively confirmed by in-situ XRD, Raman spectroscopy and H2-TPR techniques.