Synthesis and Optical Properties of Two Cobalt Oxides (CoO and Co₃O₄) Nanofibers Produced by Electrospinning Process

Abstract

In the present study, cobalt(II) oxide (CoO), which is hard to synthesize because of the chemical activity of cobalt metal, and the popular cobalt(II, III) oxide (Co 3 O 4 ) have been successfully produced in smooth and continuous nanofibrous form by using the electrospinning technique. An aqueous cobalt acetate tetrahydrate and poly(vinyl alcohol) mixture has been electrospun and vacuously dried at 80 °C. Pure, smooth and solid Co 3 O 4 nanofibers were produced when the dried nanofiber mats were calcined in air atmosphere at 700 °C. Water gas has been prepared by a novel technique to produce pure CoO nanofibers from the original cobalt acetate/poly(vinyl alcohol) nanofiber mats. The nanofiber mats have been hydrothermally treated in the presence of carbon at 300 °C in an especially designed reactor. The invoked physiochemical analyses have affirmed formation of both oxides in nanofibrous shape. The optical properties of the obtained nanofibers have been studied. UV-visible absorbance spectra have indicated that the band gap energy differences for the Co 3 O 4 and CoO nanofibers are 2.4 and 2.21 eV, respectively.

Silver Nanofibres by a Novel Electrospinning Process: Nanofibres with Plasmon Resonance in the IR Region and Thermal Hysteresis Electrical Conductivity Features

“…Figure 3 shows the FTIR results for the utilised silver acetate, the pristine PVA and the electrospun nanofibre mats. As shown in this figure, the characteristics absorption bands of the acetate anion which appear from 1590-600 cm -1 [37,38] can be observed in the spectra of AgOAc and the nanofibre mats. Within this range, two main peaks at 1570 and 1408 cm -1 can be clearly seen in the nanofibre mats and the pure AgOAc spectra.…”

Synthesis and characterization of maghemite iron oxide (γ-Fe2O3) nanofibers: novel semiconductor with magnetic feature

“…This technique involves the use of a high voltage to charge the surface of a polymer solution droplet and thus to induce the ejection of a liquid jet through a spinneret. Due to bending instability, the jet is subsequently stretched by many times to form continuous, ultrathin fibers [36]. Figure 1 shows a schematic diagram for the standard electrospinning set-up which has been used in the present study.…”

Low-temperature synthesis of core/shell of Co3O4@ZnO nanoparticle characterization and dielectric properties

“…4a. The bulk zinc oxide (ZnO) has wide bandgap (WBG) of 3.37 eV, the semiconductors (WBG) are semiconductor materials which have a relatively large bandgap compared to conventional semiconductors [14], and the bulk Co 3 O 4 has a bandgap between 2.85 and 1.70 eV [15]. The optical absorption spectrum of CZ core/ shell NPs has been carried out using UV-Vis spectrophotometer.…”