铜锌催化剂组分间相互作用的研究

INTERACTION AMONG THE COMPONENTS OF COPPER-ZINC WATER-GAS SHIFT CATALYSTS

本文用ICP、XRD和TPD-MS(O_2)等技术研究了铜锌催化剂组分间的相互作用,发现氧化态Cu-Zn催化剂中部分ZnO熔于CuO中生成了(Cu,Zn)O固熔体。低温变换反应条件下的Cu-Zn催化剂处于还原态,它与氧化态的主要差别在于失去了(Cu,Zn)O的晶格氧。研究了Cu-Zn-Mn催化剂中部分Mn进入ZnO晶格生成(Zn,Mn)O固溶体及其对变换反应活性的影响。本文还用TPD-MS(O_2)技术考察了添加Mn、Al等组分对Cu-Zn催化剂组分间相互作用的影响。

Interaction among the components of catalysts, based on copper-zinc, Cu-Zn-Al, Cu-Zn-Mn, and Cu-Zn-Al-Mn, has been investigated by the techniques of In ductively Coupled Plasma(ICP), X-Ray Diffraction(XRD), and Temperature Programmed Desorption/ecomposition-Mass Spectrography detecting oxygen(TPD-MS(O_2)). It has been revealed that for Cu-Zn catalysts in oxidation state, a parte of Zno goes into CuO to form (Cu, Zn)O solid solution. Under the low temperature shift condition, the Cu-Zn catalysts are converted to being at the reduction state with the loss of lattice oxygen originally contained in the (Cu, Zn)O solid solution.Compairison of the d spacings of ZnO in the catalysts after activity determination with that of the JCPDS cards (Table 5) shows that a part of Mn^(2+) substitutes Zn^(2+) in the ZnO phase, forming (Zn, Mn)O solid solution. It has been proved that the addition of Mn to Cu-Zn catalyst not only enlarges the specific surface area but also enhences the number of active center per unit area.The results of TPD-MS(O_2) studies show that the addition of the components of Mn or Al to the Cu-Zn catalyst affect the interaction among thc components of Cu-Zn catalysts.