Iron oxide (Fe2O3) synthesized via solution-combustion technique with varying fuel-to-oxidizer ratio: FT-IR, XRD, optical and dielectric characterization

• Published in: Materials chemistry and physics Vol. 286; p. 126118
• Main Authors: Kashyap, Shreyas J., Sankannavar, Ravi, Madhu, G.M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.07.2022; Elsevier BV
• Subjects: Combustion; Crystallites; Dielectric properties; Diffuse reflectance spectroscopy; Electron micrographs; Energy dispersive X ray spectroscopy; Ferric oxide; Fourier transforms; Frequency analysis; Fuel-to-oxidizer ratio; Fuels; Functional groups; Gamma phase; Glycine; Infrared spectroscopy; Iron oxide; Iron oxides; Nanoparticles; Optical properties; Oxidizing agents; Rietveld refinement; Spectrum analysis; Synthesis; Thermal analysis; Thermogravimetric analysis; Ultraviolet reflection; X ray powder diffraction; XRD; Iron oxide; Rietveld refinement; Fuel-to-oxidizer ratio; XRD; Dielectric properties
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2022.126118

This study addresses the effect of fuel-to-oxidizer ratio (∅ =1.47, 1.57, 1.67, 1.77 and 1.87) on the structural, optical and dielectric properties of iron oxide nanoparticles synthesized through solution-combustion technique with glycine as the fuel. The synthesized samples were characterized using scanning electron microscopy, energy dispersive X-ray (EDX) spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), ultraviolet–visible (UV-VIS) diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRPD) with Rietveld refinement, thermogravimetric analysis (TGA) and frequency-dependent dielectric analysis. Electron micrographs show no change in morphology with respect to ∅. The EDX results revealed the existence of Fe and O. FT-IR confirmed the metal-oxygen (M − O) functional groups of iron oxides typically present near ∼ 570 and ∼ 520 cm−1. The synthesized samples showed typical reflectance spectrum of iron oxides during UV–Vis DRS analysis, where the maximum optical band gap of 1.80 eV was displayed by Fe2O3 with ∅ = 1.67. The diffraction peaks were indexed with two phases: α-Fe2O3 and γ-Fe2O3. It was observed that the γ-phase decreased as ∅ increased. Rietveld refinement showed that ∅ = 1.47 had γ-phase as the majority (96.46 wt%), while ∅ = 1.87 had α-phase as the majority (79.90 wt%). The average crystallite size of α-phase was found to be 44.72 nm, while that of the γ-phase was 27.53 nm. The real and imaginary parts of dielectric constant, dielectric tangent loss, electric modulus, impedance and ac conductivity with respect to varying frequency were studied. All the parameters display typical trends shown by Fe-based ceramics agreeing to the Maxwell-Wagner type of interfacial polarization. The modulus studies revealed that the samples show non-Debye type relaxations and it can be concluded that these materials are well suited for high-frequency applications. •Fe2O3 was prepared by solution-combustion method with varying fuel-to-oxidizer ratio (1.47–1.87).•All the prepared samples have tetragonal and rhombohedral crystal structures.•The samples exhibited low dielectric loss and good stability over the frequency range studied.•AC electrical conductivity increased with increasing frequency.