Microwave-assisted additive free synthesis of nanocrystalline zinc oxide

Ultra-Fast Growth of ZnO Nanorods on Cotton Fabrics and Their Self-Cleaning and Physiological Comfort Properties

The main aim of the present study was to investigate the effect of microwave irradiation time on the photocatalytic and physiological comfort characteristics of zinc-oxide-nanorod-coated cotton fabrics. An ultra-fast technique was employed to grow the zinc oxide nanorods on cotton fabrics using a microwave-assisted hydrothermal method. The axial (length) and lateral (diameter) growth of the zinc oxide nanorods was observed to increase with microwave irradiation time. The ZnO nanorods uniformly and entirely covered the cotton fibers. The surface morphology, topography and chemical characteristics of the ZnO nanorods were investigated by scanning electron microscopy (SEM), EDS analysis, X-ray diffraction (XRD), atomic force microscopy (AFM) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The degradation of orange II dye under UV light irradiation was observed to assess photocatalytic self-cleaning and solution discoloration ability. The ZnO-nanorod-coated cotton fabrics exhibited excellent photocatalytic activity, as the stains of orange II dye disappeared predominantly within 4 h and the coated fabrics became almost white after 6 h. Analyses of thermal properties, water vapor permeability (WVP), air permeability and stiffness were also performed to investigate the physiological comfort of the ZnO-nanorod-coated fabrics. The thermal conductivity and thermal absorptivity were observed to increase with an increase in the size and density of the ZnO nanorods. Moreover, non-significant reductions in water vapor permeability and air permeability were observed with application of the ZnO nanorods. The stiffness of the ZnO-nanorod-coated cotton fabric increased due to the complete coverage of fibers by the uniform growth of the ZnO nanorods. The ZnO-nanorod-coated cotton fabrics also showed good washing durability and reusability.

A Review of Microwave Synthesis of Zinc Oxide Nanomaterials: Reactants, Process Parameters and Morphoslogies

Zinc oxide (ZnO) is a multifunctional material due to its exceptional physicochemical properties and broad usefulness. The special properties resulting from the reduction of the material size from the macro scale to the nano scale has made the application of ZnO nanomaterials (ZnO NMs) more popular in numerous consumer products. In recent years, particular attention has been drawn to the development of various methods of ZnO NMs synthesis, which above all meet the requirements of the green chemistry approach. The application of the microwave heating technology when obtaining ZnO NMs enables the development of new methods of syntheses, which are characterised by, among others, the possibility to control the properties, repeatability, reproducibility, short synthesis duration, low price, purity, and fulfilment of the eco-friendly approach criterion. The dynamic development of materials engineering is the reason why it is necessary to obtain ZnO NMs with strictly defined properties. The present review aims to discuss the state of the art regarding the microwave synthesis of undoped and doped ZnO NMs. The first part of the review presents the properties of ZnO and new applications of ZnO NMs. Subsequently, the properties of microwave heating are discussed and compared with conventional heating and areas of application are presented. The final part of the paper presents reactants, parameters of processes, and the morphology of products, with a division of the microwave synthesis of ZnO NMs into three primary groups, namely hydrothermal, solvothermal, and hybrid methods.

A Template-Free Microwave Synthesis of One-Dimensional Cu₂O Nanowires with Desired Photocatalytic Property

One-dimensional Cu₂O nanowires were successfully prepared with a template-free microwave synthesis. Neither a surfactant was needed (to induce the growth), nor a long reaction time was required for this method. The structural investigation confirmed the successful preparation of Cu₂O. The morphology images showed that the radial size of the Cu₂O nanowires was 10 nm. The possible growth mechanism was hypothesized according to morphology evolution and references. A series of time-dependent experiments indicated that as time increased, Cu₂O primary particles grew radially into nanowires under microwave energy irradiation. The condition-variable tests revealed that the suitable quantity of NaOH played a vital role in Cu₂O nanowire formation. The photocatalytic property of the sample was investigated by degradation of methyl orange under the irradiation of visible light at room temperature. Benefiting from its unique large surface area, 4 mg of the prepared catalyst degraded 73% of methyl orange (10 mg L⁻¹) in 120 min.

Morphological study of microwave-assisted facile synthesis of gold nanoflowers/nanoparticles in aqueous medium and their catalytic application for reduction of p-nitrophenol to p-aminophenol

The present work reports a facile synthesis of gold (Au) nanoflowers and nanoparticles with various morphologies using different microwave powers in watts in DMSO.

Additive-free 1,4-butanediol mediated synthesis: a suitable route to obtain nanostructured, mesoporous spherical zinc oxide materials with multifunctional properties

A family of mesoporous, self-aggregated zinc oxide materials with spherical morphologies of high crystalline quality, is obtained through a facile, additive-free polyol procedure.

A facile one-step approach for the synthesis of uniform spherical Cu/Cu2O nano- and microparticles with high catalytic activity in the Buchwald–Hartwig amination reaction

An efficient, rapid, and additive-free protocol for synthesis of uniform spherical Cu/Cu₂O nano/microparticles and application in Buchwald–Hartwig amination reaction.

A facile and rapid route for the synthesis of Cu/Cu2O nanoparticles and their application in the Sonogashira coupling reaction of acyl chlorides with terminal alkynes

This work reports a simple, rapid and efficient protocol for synthesis of Cu/Cu₂O nanoparticles. The prepared Cu/Cu₂O nanoparticles were effectively utilized for Sonogashira coupling reaction of acyl chlorides with terminal alkynes.