Microwave assisted aqueous synthesis of organosilane treated mesoporous Si@ZnO nano architectures as dual-functional, photocatalysts

Abstract

A facile aqueous synthesis has been reported for the preparation of organosilane treated ZnO nano architectures (Si@ZnO) via microwave strategy. An in-situ addition of 3-aminopropyl trimethoxy silane (APTMS) resulted in the formation of polysiloxane network that effectively controlled the exaggerated growth of ZnO finally produced high surface area, mesoporous Si@ZnO nano clusters. The formation of a polysiloxane network was confirmed from the FTIR analysis. Reduction in the crystallite size was verified from the powder X-ray diffraction and TEM analyses. Silane treated ZnO shows highly stable dispersion, in aqueous medium. The quantum confinement effect of size controlled Si@ZnO was confirmed from the blue shift in UV–vis absorption spectra. As a function of APTMS concentration both surface charge and surface area was found to enhance from (−12) to (+35.5)mV and 18 to 80m2g−1, respectively. Such positively charged Si@ZnO nano architectures showed property highly receptive to anionic dyes for the adsorption as well as photodegradation. In this study, size controlled, surface engineered, dual-functional photoactive adsorbent is successfully designed which is potentially useful for the recovery and recycling of dye contaminated water.