Specific Adsorption and Redox Features of CuZSM-5--Effect of Ion-Exchange Methods

摘要

CuZSM-5 samples exhibit a prominent adsorption feature for N_2 molecules at 298 K and its property has varied depending on the preparative methods used. The chemisorpiton of N_2 was observed for the CuZSM-5 (NM) sample at 298 K, as well as the high adsorption propensity of the CuZSM-5 (P) sample for an N_2 molecule. These facts can be explained quite naturally as due to the occurrence of the site-selective ion-exchange in the respective ion-exchange processes. In addition, there is direct evidence for the existence of metallic copper clusters, which are formed by an ion-exchange procedure by the microwave method using an aqueous solution of CuCl_2, followed by heat treatment at above 673 K in vacuo. The site-selective analysis of the copper ion exchanged is in progress.