Application of the xenon-adsorption method for the study of metal cluster formation and growth on Y zeolite

摘要: Supported metal clusters of Pt, Ir, Ru, Rh, and Pd were prepared in the supercage Y zeolite by activating their ion-exchanged ammine complexes. Zenon adsorption isotherms obtained from these samples at temperatures ranging 296 to 340 K pressures up 500 Torr, as well chemical shift data {sup 129}XeNMR study adsorbed xenon gas, indicate that can occur quite strongly, becoming saturated above ca. 50 on cluster surface whereas is so weak support quantity increases linearly with pressure according Henry`s law. An application such a simple technique for Pt formation NaY indicates size formed does not change significantly content changed 2 10%. This xenon-adsorption method has also been very useful growth Ru zeolite. There result small are treating precursor, which heating an aqueous ammonia solution RuCl{submore » 3}, vacuum 623 K. The grow gradually high both H{sub 2} under vacuum. agree exposure supported O{sub 423 causes excessive migration species, resulting large agglomeration. Another example, further promise wide applicability method, various X zeolites. Ca{sup 2+}, Y{sup 3+}, perhaps other multivalent cations residing necessary obtain 1-nm univalent give larger clusters.« less