载钴沸石上Co^(3+)的还原作用

The Reduction of Co^(3+)ions on Co-Supported ZSM-5 Zedlite

本文釆用XRD,XPS,TGA和TPR-XRD技术考察浸渍钴HZSM-5沸石催化剂的还原作用,结果表明:浸渍型载钴沸石经焙烧后,钴主要以Co_3O_40.形态存在于沸石外表面,其粒度为350(?)左右。同时有部分钴离子进入孔内与H^+进行交换,以类似Co(OH)_2形态存在于沸石内表面。500℃还原后,还原度随载钴量增加而增大,其大于57%,粒度在250-270(?)间。还原过程中,出现2个TPR峰,分别相应于过程中的Co^(3+)→Co^(2+)→Co二个阶段,各阶段的特征温度依次为:591-624°K;644-658°K。

The reduction effect of impregnated Co / HZSM-5 zeolite his been studied by XRD, XPS. TGA, orTPR-XRD, It showed that after the zeolite was calcined, most co^(3+) existed on the external surface of the zeolite in the state of Co_3O_4, the particle size was 350. while a part of Co^(2+) exchanged whith H^+ in the pore and existed in the form of Co(OH)_2 on inte rnal surface. After reduction at 500℃, the reduction degree was relevant to the amoun of suppo rted cobalt, it could be 57% or more. the particle size was 250-270. Two peaks appeared in TPR spectra corresponding Separatly to Co^(3+)→Co^(2+)→C^0o, two periods during the reduction, and characteristic tenmperature of each period was 591-624° K, 644-658°K. respectively.