G D Prasanna

Bio: G D Prasanna is an academic researcher from Kuvempu University. The author has contributed to research in topics: Materials science & Polyaniline. The author has an hindex of 4, co-authored 10 publications receiving 139 citations.

Structural and dielectric properties of Fe doped ZnO nanoparticles

Abstract: Nano-sized Zn1−xFexO (where x = 0.00, 0.005, 0.01, 0.02, 0.03, 0.04) powders have been prepared by solution combustion method. The powder samples have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectra, scanning electron microscope (SEM) and energy dispersive analysis of X-rays (EDAX). The XRD patterns showed the formation of single phase wurtzite structure. The average particle size is found to be in the range of 19–34 nm. SEM images show high porosity in the material. The dielectric studies have been performed at room temperature in the frequency range 1 kHz–5 MHz and different mechanisms were used to explain the observed behavior.

Low-Frequency Dependence of Conductivity and Dielectric Properties of Polyaniline/ZnFe 2 O 4 Nanocomposites

Abstract: Conducting polyaniline/ZnFe2O4 nanocomposites are synthesized by using a simple and inexpensive one-step in-situ polymerization method in the presence of ZnFe2O4 nanoparticles. The structural, morphological and electrical properties of the samples are characterized by x-ray diffraction, Fourier transform infrared spectra and scanning electron microscopy. These results reveal the formation of polyaniline/ZnFe2O4 nanocomposites. The morphology of these samples is studied by scanning electron microscopy. Further, the ac conductivity (σac) of these composites is investigated in the frequency range of 1 kHz–10 MHz. The presence of polarons and bipolarons are responsible for the frequency dependence of ac conductivity in these nanocomposites. The ac conductivity is found to be constant up to 1 MHz and thereafter it increases steeply. The ac conductivity of 0.695 Scm−1 at room temperature is observed as the maxima for the polyaniline with 40wt% of the ZnFe2O4 nanocomposite.

Photocatalytic Oxidation of Dye Bearing Wastewater by Iron Doped Zinc Oxide

Abstract: In the present study, photocatalytic oxidation of dye bearing wastewater has been done using iron doped zinc oxide (Fe/ZnO) photocatalyst. Various photocatalysts were synthesized by solution combustion synthesis method, and their structural, morphological, and optical properties were studied using N2 adsorption–desorption, Fourier transform infrared spectroscopy, X-ray diffractometer, thermogravimetric analysis, field emission scanning electron microscope, transition electron microscope, and UV–visible diffuse reflectance spectra. Effect of various parameters such as the amount of iron doped, calcination temperature, calcination time, pH of the dye solution, catalyst dose, hydrogen peroxide dose, reaction temperature, and initial concentration of the dye solution were optimized. At optimum conditions, more that 71% color removal, 94% dye degradation, and 41% total organic carbon removal was observed for acid red 1 dye solution having an initial concentration of 50 mg/L and initial color of 2730 Pt:Co units.

Solvothermal synthesis of CoxFe3−xO4 spheres and their microwave absorption properties

Abstract: CoxFe3−xO4 (x = 0–1) spheres are synthesized via a solvothermal reaction using ethylene glycol (EG) as a solvent They are characterized, and the results show that the prepared spheres are mainly 300–500 nm in diameter and constituted by small grains For the EG solution containing stoichiometric ingredients (atomic ratio of Co2+:Fe3+ = 1:2), the obtained spheres are Co09Fe21O4 at 200 °C (sphere A) and Co074Fe226O4 (sphere B) at 300 °C, whose crystallites are 23 nm and 30 nm in size, respectively VSM measurements reveal improved properties with sphere B Variations of complex permittivity and permeability for different composite (75% mass ratio of spheres) have been studied as a function of frequency The calculated reflectivity value indicates that the composite containing sphere A displays better microwave absorption capability The minimum reflection loss reaches −41089 dB at 1208 GHz, with a matching thickness of 2 mm The dielectric loss contributes even more than magnetic loss in the frequency range of 3–14 GHz The synergistic effect of dual losses makes the submicrosphere a promising absorbent in X and Ku bands The composite consisting of sphere B is inferior in dielectric properties owing to ferrous ion migration from octahedral to tetrahedral sites and due to the big crystallites lacking defects After the calcination treatment of the spheres at 700 °C, the dielectric loss turns out to be low due to the disappearing Fe2+ ↔ Fe3+ pairs in adjacent octahedral sites and the loss of defects Variations of the cobalt ratio in spheres can change the resonance frequency and crystallinity of the spheres and ultimately the minimum reflection loss and corresponding frequency band The microwave absorption properties of mixed magnetite and cobalt ferrite spheres are influenced by the cationic stoichiometry and crystalline integrity