Can hydrogen be responsible for the catalytic activity of Sc- and Zr-Y zeolites?

Abstract

The spectra of scandium and zirconium exchanged forms of type Y zeolites have been investigated using an NMR technique. The zeolites were activated in vacuum at various temperatures before the NMR spectra were taken. A broad line was observed indicating the presence of water molecules in the zeolites. On heating the zeolites, the line diminished and at the same time a narrow line grew. The increase in intensity of the narrow line is considered to result from the destruction of the zeolite structure rather than simply from the dissociation of water molecules into H + and OH -, i.e. with the formation of Brönsted acid sites.