Tin oxide surfaces. Part 2.—Infra-red study of the adsorption of pyridine and ammonia on tin(IV) oxide
Abstract
The adsorption of pyridine and ammonia on tin(IV) oxide has been studied by infra-red spectroscopy. The surface exhibits Lewis acidity but does not show any Brönsted acidity towards these bases even in the presence of water vapour.
It has also been shown that when ammonia cations are formed on the surface (by preadsorption of HCl), they are not free to rotate. In addition, when HCl is added to a damp surface, the molecular water is protonated to give hydroxonium ions which are evidenced by their infra-red spectrum.