CuO/CeO2-Al2O3催化剂中CuO物种的原位XRD、Raman和TPR表征

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.

Characterization of CuO Species in CuO/CeO2-Al2O3 Catalysts by In-situ XRD, Raman Spectroscopy and TPR

CuO species and thermal solid-solid interaction in CuO(w,%)/ 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.