Structural and optical properties of sol-gel derived α-Fe2O3 nanoparticles

Mathevula, L.E.; Noto, L.L.; Mothudi, B.M.; Chithambo, M.L.; Dhlamini, M.S.

doi:10.1016/j.jlumin.2017.07.055

Cited by 58 publications

(22 citation statements)

References 38 publications

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“…In samples F25, F30 and F40, band II is completely removed and the intensity of band I increases compared with that of samples with lower Fe contents. This can be related to the formation of an additional Fe 2 O 3 phase, confirming the results of the DRS analysis (Mathevula et al, 2017). The luminescence of band I may be related to emission from shallow defect levels such as Zn 0…”

Section: Figure 11supporting

confidence: 83%

Mechanistic insights into defect generation and tuning of optical properties in Zn_1−xFe_xAl₂O₄(0.01 ≤x≤ 0.40) nanocrystals

Jain

Manju

Vashishtha

et al. 2020

Acta Crystallogr Sect B

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The correlation of several defects and optical and magnetic properties with Fe content in Zn1−x Fe x Al2O4 (0.01 ≤ x ≤ 0.40) nanocrystals has been scrutinized through X-ray diffraction, O K-edge X-ray absorption near-edge structure, FT–IR, diffuse reflectance, photoluminescence and electron spin-resonance spectroscopies, and vibrating sample magnetometry. Increasing Fe content causes elongation in the octahedral units of the lattice, accompanied by distortion in the octahedral coordination. Fe introduces non-radiative centres in the forbidden gap, thereby tuning the band gap from 4.37 to 3.88 eV and eliminating emission in the visible region. Zn vacancies are found to tail off, while {\rm Fe}_i^{\bullet \bullet \bullet}, {\rm Al}_{\rm Zn}^\bullet and FeAl × antisite defects increase in concentration with increasing Fe content. Inhomogeneous broadening of spin-resonance signals infers strong spin-lattice interactions of Fe3+ ions at distorted octahedral and non-symmetric tetrahedral sites. A transition is observed from paramagnetism to superparamagnetism at higher Fe concentrations. A visual colour change from pearly white to orange–brown is observed in Zn1−x Fe x Al2O4 nanocrystals with increasing Fe content, revealing its potential candidature for pigments in the paint and dye industries.

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Section: Figure 11supporting

confidence: 83%

Mechanistic insights into defect generation and tuning of optical properties in Zn_1−xFe_xAl₂O₄(0.01 ≤x≤ 0.40) nanocrystals

Jain

Manju

Vashishtha

et al. 2020

Acta Crystallogr Sect B

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“…Figure 1 shows the X-ray diffraction (XRD) pattern of the prepared sample annealed at 500 °C for 2 h. The diffraction peaks can be readily indexed to the rhombohedral (hexagonal) structures of hematite (JCPDS No: 33-0664) [29] with the lattice parameters a = b = 5.0387 Å and c = 13.767 Å. The peaks of hematite phase are located at 2θ = 24.11°, 33.16°, 35.56°, 40.87°, 49.43°, 53.96°, 62.46°, and 64.02°; they are assigned to (012), (104), (110), (113), (024), (116), (214), and (300) planes, respectively.…”

Section: Resultsmentioning

confidence: 99%

NO2 Selective Sensor Based on α-Fe2O3 Nanoparticles Synthesized via Hydrothermal Technique

Hjiri

Aida

Neri

2019

Sensors

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In the present work, hematite (α-Fe2O3) nanopowders were successfully prepared via a hydrothermal route. The morphology and microstructure of the synthesized nanopowders were analyzed by using scanning and transmission electron microscopy (SEM and TEM, respectively) analysis and X-ray diffraction. Gas sensing devices were fabricated by printing α-Fe2O3 nanopowders on alumina substrates provided with an interdigitated platinum electrode. To determine the sensor sensitivity toward NO2, one of the main environmental pollutants, tests with low concentrations of NO2 in air were carried out. The results of sensing tests performed at the operating temperature of 200 °C have shown that the α-Fe2O3 sensor exhibits p-type semiconductor behavior and high sensitivity. Further, the dynamics exhibited by the sensor are also very fast. Lastly, to determine the selectivity of the α-Fe2O3 sensor, it was tested toward different gases. The sensor displayed large selectivity to nitrogen dioxide, which can be attributed to larger affinity towards NO2 in comparison to other pollutant gases present in the environment, such as CO and CO2.

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“…The crystalline size of α-Fe 2 O 3 nanoparticles samples showed values between 15 and 30 nm, with a removal efficiency of chromium near 50% to smaller particles. Sol-gel method was applied by [46] to form hematite nanoparticles from Fe(NO 3 ) 3 •9H 2 O dispersed in ethanol. The particles produced by this method possess sizes below 10 nm and excellent optical properties, with a band gap energy near 2 eV.…”

Section: α-Hematite (Fe 2 O 3 )mentioning

confidence: 99%

Photocatalytic Adsorbents Nanoparticles

Colpani¹,

Dal’Toé²,

Zanetti³

et al. 2019

Advanced Sorption Process Applications

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Photocatalysis and high adsorption coupling in a same nanoparticle have been emerged as a prominent class of cost-effective materials to degrade recalcitrant contaminants in wastewater. α-Hematite, metal-organic frameworks and TiO 2 nanocomposites have been investigated due to their features that overcome the other conventional photocatalysts and adsorbents to remove contaminants in aqueous medium. Several methods are applied to synthesize these nanostructures with different properties and physicochemical features and a brief review is shown to these well-established techniques to provide an understanding for the construction and application of these advanced materials.

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Structural and optical properties of sol-gel derived α-Fe2O3 nanoparticles

Cited by 58 publications

References 38 publications

Mechanistic insights into defect generation and tuning of optical properties in Zn_1−xFe_xAl₂O₄(0.01 ≤x≤ 0.40) nanocrystals

Mechanistic insights into defect generation and tuning of optical properties in Zn_1−xFe_xAl₂O₄(0.01 ≤x≤ 0.40) nanocrystals

NO2 Selective Sensor Based on α-Fe2O3 Nanoparticles Synthesized via Hydrothermal Technique

Photocatalytic Adsorbents Nanoparticles

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Structural and optical properties of sol-gel derived α-Fe2O3 nanoparticles

Cited by 58 publications

References 38 publications

Mechanistic insights into defect generation and tuning of optical properties in Zn1−xFexAl2O4(0.01 ≤x≤ 0.40) nanocrystals

Mechanistic insights into defect generation and tuning of optical properties in Zn1−xFexAl2O4(0.01 ≤x≤ 0.40) nanocrystals

NO2 Selective Sensor Based on α-Fe2O3 Nanoparticles Synthesized via Hydrothermal Technique

Photocatalytic Adsorbents Nanoparticles

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Mechanistic insights into defect generation and tuning of optical properties in Zn_1−xFe_xAl₂O₄(0.01 ≤x≤ 0.40) nanocrystals

Mechanistic insights into defect generation and tuning of optical properties in Zn_1−xFe_xAl₂O₄(0.01 ≤x≤ 0.40) nanocrystals