Inception and Trapping of ZnO Nanoparticles within Desilicated Mordenite and ZSM‐5 Zeolites

Abstract ZnO nanoparticle inception within mordenite and ZSM‐5 zeolites, of varied Si/Al ratios, was achieved via the exchange of zeolite cations with Zn²⁺, followed by NaOH leaching, and thermal treatment at 550 °C under O₂. ZnO particles were observed by electron microscopy; further characterization included X‐ray diffraction, thermogravimetric analysis, and N₂ sorption. NaOH addition caused a partial desilication of mordenite and ZSM‐5 zeolites as shown by a decreased Si/Al ratio. The bulk and surface Zn and Al concentrations were measured by ICP‐AE spectrometry and XPS, respectively. N₂ sorption isotherms on ZnO/zeolite specimens indicated the existence of micropores and mesopores; the amounts of them in mordenite and ZSM‐5 zeolites were determined from adsorption data at low pressures. The progressive growth of ZnO nanoparticles induced some micropore widening as well as the inception of a slit‐like intrazeolite mesoporosity due to the desilication of the substrate during the NaOH leaching process. The final zeolite products are potentially useful as they are endowed with a twofold micro‐mesoporosity.