CuO/La_2O_3-Al_2O_3催化剂中CuO物种的迁移和高温固相反应

Transference of CuO Species and Solid-Solid Interaction in CuO/La_2O_3-Al_2O_3 Catalyst

采用XRD、激光Raman光谱和TPR技术研究了CuO/La2O3-Al2O3催化剂中CuO高温迁移及固相反应。结果表明,800℃焙烧的CuO(20%)/La2O3(x%)-Al2O3催化剂,低La2O3负载量(5%和10%)时,La2O3(x%)-Al2O3载体表面即存在CuO和少量CuAl2O4;当La2O3负载量增大(≥20%)时,由于La2O3的阻止作用,使得CuO无法迁移到La2O3内层和Al2O3反应生成CuAl2O4,从而使CuO稳定存在于催化剂表层。高温焙烧(≥900℃),La2O3的隔离作用下降,从而导致生成CuAl2O4。

CuO species and thermal solid-solid interaction in CuO/La2O3-Al2O3 were investigated by XRD, Raman spectroscopy and H2-TPR technique. The experimental results show that for CuO/La2O3 （x%）- Al2O3 catalysts calcined at 800℃, both CuO and a small quantity of CuAl2O4 present on the surface of the La2O3 （x%）-Al2O3 support with the low content of La2O3. With increasing the content of La2O3, it can effectively hinder the transference of CuO into the internal of La2O3 layer and the formation of CuAl2O4. With further increasing the calcined temperatures, the function of separation of La2O3 decreases, then CuAl2O4 forms as a result of solid-solid interaction between CuO and Al2O3.