ZnO as an efficient nucleating agent and morphology template for rapid, facile and scalable synthesis of MOF-46 and ZnO@MOF-46 with selective sensing properties and enhanced photocatalytic ability

Abstract

MOF-46 and a novel core-shell heterostructure containing ZnO@MOF-46 rods have been successfully synthesized via a simple, versatile and economic method. The products have been characterized by X-ray diffraction (XRD), FTIR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Time and solvent effects on the growth process of ZnO@MOF-46 were investigated. Luminescent properties of the activated sample showed distinct solvent-dependent photoluminescence emissions. The product also demonstrated unique sensing properties in detection of aromatic compounds via a fluorescence quenching and enhancing mechanism. Aromatic compounds with electron-withdrawing substituents such as nitro act as fluorescence quenchers for ZnO@MOF-46 and aromatic compounds with electron-donating substituents such as CH3 were found to enhance the ZnO@MOF-46 fluorescence. The ZnO@MOF-46 showed excellent photodegradation of methylene blue. The degradation rates in presence of various scavengers including benzoquinone, isopropyl alcohol and ammonium oxalate (O2 •-, OH • and h + scavengers, respectively) were studied and the results showed all of species (O2 •-, OH • and h + ) contribute to degradation but the OH • is the main active species and plays a major role in this system and hence photocatalyst degradation was supposed to have a radical mechanism. Band structure parameters of ZnO@MOF-46 were determined using cyclic voltammetry and DRUV/VIS spectroscopy and the mechanism of photodegradation was then discussed.

A sustainable multi-function biomorphic material for pollution remediation or UV absorption: Aerosol assisted preparation of highly porous ZnO-based materials from cork templates

“…Comparing with ZnO literature, some studies report similar behaviour while others are different. •OH radicals, for instance, were described as significant/dominant species, for both undoped and doped compounds [41][42][43], similar to what was observed in this work. •O2 -, on the other hand, has also been reported to be involved in the photocatalysis [41,44], in opposition to what reported here.…”

Sustaining energy systems using metal oxide composites as photocatalysts

“…In the case of ZnO@MOF-46 photocatalyst, the role of °OH was prominent in accelerating the decolorization of MB. The dye was degraded up to 81% in 3h under UV irradiation which was a significant improvement over the 41.5% and 51% in the presence of individual ZnO and MOF-46, respectively [3]. The formation of ZnO@ZIF-8 core-shell heterostructures depended on the concentration of 2-methylimidazole during its synthesis using ZnO colloidal spheres as templates.…”

Metal–Organic Framework‐Based Materials for Solar Water Splitting

“…Zn‐based MOF materials have been applied in PEC research due to their capability to form heterostructure for improved charge separation. [ 42,43 ] For example, Peng et al fabricated Zn and Ni mixed‐metal MOF‐coated ZnO nanowire array (ZnNi‐MOF@ZnO) photoanode through ion‐exchange processing, as shown in Figure a. [ 42 ] The covalent interactions between ZnO and MOF may create intimate interfacial contact, which accelerates charge transfer to the reaction interface under illumination.…”