1H Magic Angle Spinning NMR Evidence for Dissociative Adsorption of Hydrogen on Ag+-Exchanged A- and Y-Zeolites

1 H magic angle spinning NMR gave firm evidence for formation of acidic protons (4.0 ppm) and hydride species (−1.8 ppm), where the former exists as OH groups (acidic protons) and the latter has an interaction with three equivalent Ag atoms, existing as Ag 3 H when Ag + -exchanged A-zeolite is reduced with hydrogen. The formations of Ag 3 H and of acidic protons by the heterolytic dissociation of H 2 over Ag 3 + are reversible. The heterolytic dissociation of H 2 was also observed over Ag-Y-zeolite, the silver hydride species being observed at −0.1 ppm.