摘要
分别用离子交换法和等体积浸渍法制备了 2 0 %Zn/HZSM 5催化剂 ,并对催化剂中锌组分的不稳定性进行了研究 .高温还原条件下 ,锌由催化剂中缓慢流失 ,而氧化条件下锌组分是稳定的 .锌在氢热处理条件下的流失速率与催化剂的制备方法有关 ,锌组分的稳定性与锌在沸石上的分布及锌物种的状态有关 .将离子交换法制备的Zn/HZSM 5在 5 5 0℃下氢处理 2 0h ,并分别用XRD ,TEM ,XPS以及丙烷芳构化反应评价对其理化性质进行了表征 .结果表明 ,该催化剂保持了沸石阳离子交换位锌物种的存在 。
The instability of Zn component in 2 0%Zn/HZSM 5, prepared by ion exchange (Zn/HZSM 5(e)) and impregnation (Zn/HZSM 5(i)), was investigated. It was shown that the Zn in the catalyst was slowly eluted under reduction condition with H 2 at high temperature, but was not under oxidation condition. The Zn loss rate related to the preparation method for the catalyst. It was suggested that the stability of Zn component depends on both the distribution and the state of Zn species in Zn/HZSM 5. The variation of physicochemical properties of Zn/HZSM 5(e), before and after pretreatment with H 2 at 550 ℃ for 20 h, was investigated by XRD, TEM, XPS and C 3H 8 aromatization evaluation. The results showed that the catalyst kept the existentce of Zn species to reside at its cation sites and the catalytic activity did not decrease.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2000年第2期125-128,共4页
