The formation of oxide nanoparticles on the surface of natural clinoptilolite

Abstract

Nanoparticles of NiO, ZnO and Cu(2)O crystallize when the Ni-, Zn- and Cu-exchanged natural clinoptilolite, respectively, are dehydrated by heating in air at 550 degrees C. The dehydration of Mn-exchanged clinoptilolite does not lead to the crystallization of manganese oxide but affects the crystallinity of the host clinoptilolite lattice, which becomes amorphous. The NiO, ZnO and Cu(2)O nanoparticles are found to be randomly dispersed in the clinoptilolite matrix. The particle size varies from 2 to 5 nm and exceeds the aperture of the clinoptilolite channel (approximately 0.4 nm), suggesting that the crystallization of the oxide phases takes place on the surfaces of clinoptilolite microcrystals.