Hierarchical ZnO/zeolite nanostructures: synthesis, growth mechanism and hydrogen detection

Abstract

An improved hydrothermal method has been contrived for the synthesis of highly uniform, ordered, and monodispersed zeolite nanocrystals. An efficient impregnation of zinc on the outer surface of zeolite was carried out using aqueous solution at room temperature followed by high temperature calcination to form an interpenetrating network of hierarchical ZnO/zeolite-nanostructured assembly. The hierarchical structures offer high surface area, a porous structural network, a stimulated surface for catalytic and redox reactions, and better electron transport properties. Morphological and comprehensive structural analysis was carried out by advanced techniques including XRD, FESEM, TEM, STEM-EDS, BET and XPS, respectively. A plausible growth mechanism has been proposed for the formation of zeolite and ZnO/zeolite hierarchical nanocrystals. The hydrogen gas sensor made with these ZnO/zeolite hierarchical nanocrystals exhibited a very fast response of ∼10 s with slow recovery.