CuO-ZnO/γ-Al_2O_3催化剂的XRD和EXAFS研究  

XRD and EXAFS Study of Catalyst CuO-ZnO/γ-Al_2O_3

作　　者：王梅生[1] 赵金土[1] 任家瑛 宋兴志[1] 施国顺[2] 程广辉[2] 沈孝良[2] 马礼敦[2] 

机构地区：[1]华东师范大学,上海200062 [2]复旦大学,上海200433

出　　处：《分子催化》1993年第3期212-218,共7页Journal of Molecular Catalysis(China)

摘　　要：用XRD和EXAFS方法,通过对二元系(CuO-ZnO)及三元系(CuO-ZnO/γ-Al_2O_3)催化剂的比较分析,研究了CuO、ZnO和Cu的晶粒度变化以及γ-Al_2O_3的作用;通过对二元系及三元系催化剂氧化态、还原态和用后态的比较分析,研究了Cu和ZnO晶粒度变化以及催化剂的失活机理.The results of comparative study of catalysts CuO-ZnO/γ-A12O3 and CuO-ZnO in oxidized state, reduced state and used state are reported in this paper. 1. Both CuO and ZnO in oxidized state and both Cu and ZnO in reduced state or used state exist as Xighly dispersed crystallites. While γ-A12O3exists as highly dispersed non-crystalline state. 2. It is shown by comparative study between binary system and ternary system that, (a) in oxidized state the crystal size of CuO makes no difference between these two systems. The crystal size of ZnO is larger in the binary system than that in the ternary system, (b) In reduced state the crystal size of Cu and ZnO in the binary system is remarkabey larger than that in the ternary system, (c) In used state the crystal size of Cu and ZnO in the binary system is still larger than that in the ternary system, meanwhile, non-crystalline CuO single layers can be found in the ternary system. The effect of γ-AI2O3 is to restrain the growth of the crystal size of Cu and ZnO, and it is related to the formation of CuO single-layer in used state of the ternary system. 3. It is shown that, (a) the crystal size of ZnO in the binary system increases in the order of oxidized state, reduced state, used state. While the crystal size of Cu in the binary system increases more obviously from reduced state to used state. Cu can be seen on the surface of catalyst even with naked eyes. Therefore, the activity-loss of catalyst in the binary system is most probably related to the gathering of Cu and the growth of its crystal size, (b) the crystal size of ZnO in the ternary system increases remarkably from oxidized state to reduced state, but it changes a little from reduced state to used state. The crystal size of Cu has little or no change, and single layers of CuO is formed, which does not disappear through reduction. Therefore the activity-loss of catalyst in the ternary system is not the same as in the binary system, it is indeed related to the formation of single-layers

关 键 词：XRD EXAFS 催化剂 铜 锌 

分 类 号：O643.36[理学—物理化学]