NMR investigation of proton mobility in zeolites

H-Y and H-ZSM-5 zeolites were investigated by 1H MAS NMR spectroscopy over a wide range of temperatures (160–773 K). Signal broadening by up to a factor of 5 and signal narrowing by up to a factor of 40 could be assigned to different hydrogen-exchange reactions in the zeolites. We found that hydrogen forms of a zeolite containing ammonium ions represent ammonium-conducting materials, but in zeolites that were activated at temperatures above 673 K, the hopping of the hydrogen atoms between different aluminum sites (SiOHAl) is independent of proton vehicles.