Platinum cluster supported on Zeolite a by ion exchange of PT(NH3)(4)(2+)

Abstract

The ion exchange of Pt(NH3)42+ was found to take place easily up to 10 wt% Pt into NaA zeolite after ca. 50% of Na+ was substituted with 1/2Ca2+, due to the expansion of the α-cage aperture. The reduction of the Pt(NH3)42+ ion exchanged in CaNaA gave a small Pt cluster supported on A zeolite (Pt/CaNaA), similar to the preparation of Pt cluster supported on Y zeolite (Pt/Y). The chemisorption of H and O on 1 - 2 wt% Pt/CaNaA was similar to that of Pt/NaY containing ca. 1-nm Pt clusters, but much lower on 10 wt% Pt/CaNaA due to partial destruction of the zeolite framework. The turnover frequency for catalytic hydrogenation of cyclopropane over 1 − 2 wt% Pt/CaNaA was considerably lower than that over Pt/NaY.