First Successful Application of the Thallous Ion Exchange (TIE) Method. Preparation of Fully Indium-Exchanged Zeolite Y (FAU, Si/Al = 1.69)

Abstract

Fully indium-exchanged zeolite Y, |In+62.6(In57+)1.2|[Si121Al71O384], was prepared by thallous ion exchange (TIE), a vapor phase ion exchange method. InCl(g, 510 Pa) was allowed to react with a single crystal of Tl71–Y under anhydrous conditions at 623 K. A second crystal prepared as above was washed with deionized water and redehydrated to give |In+39.7 (In57+)4.5|[Si121Al71O384]. The structures of fully dehydrated Tl71–Y and these two forms of In–Y were determined by single-crystal crystallography using synchrotron X-radiation. Then the two In–Y crystals were subjected to scanning electron microscopy energy-dispersive X-ray (SEM-EDX) analysis. Both methods indicated that no Tl remained in the In–Y crystals. The additional steps of washing and redehydration caused some of the In+ ions in the first In–Y crystal to disproportionate to give additional In57+ clusters in the sodalite cavities and In0 atoms on the crystal surface. Most of the In+ ions in both forms of In–Y are easily accessible to guest molecu...