Synthesis of Porous Network-Like α-Fe2O3 and α/γ-Fe2O3 Nanoparticles and Investigation of Their Photocatalytic Properties

Ghasemifard, Mahdi; Heidari, G.; Ghamari, Misagh; Fathi, Elham; Izi, M.

doi:10.1134/s1995078019040062

Cited by 6 publications

(4 citation statements)

References 27 publications

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“…Biphasic α/γ-Fe 2 O 3 exhibits significantly higher sensitivity than α-Fe 2 O 3 and γ-Fe 2 O 3 alone [57]. The work [58] reports higher photocatalytic activity of heterophase α/γ-Fe 2 O 3 during methylene blue oxidation due to a decrease in the rate of electron-hole pair recombination. Therefore, a new approach to enhance metal oxide catalyst performance is to integrate different crystalline forms of the same metal oxide into a single structure.…”

Section: Introductionmentioning

confidence: 78%

Magnetically Separable Mixed-Phase α/γ-Fe2O3 Catalyst for Photo-Fenton-like Oxidation of Rhodamine B

et al. 2023

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Iron oxides are widely used as catalysts for photo-Fenton-like processes for dye oxidation. In this study, we report on the synthesis of an α/γ-Fe2O3 mixed-phase catalyst with magnetic properties for efficient separation. The catalyst was synthesized using glycine–nitrate precursors. The synthesized α/γ-Fe2O3 samples were characterized using scanning electron microscopy, X-ray diffraction spectroscopy (XRD), Raman shift spectroscopy, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM). The diffraction peaks were indexed with two phases, α-Fe2O3 as the main phase (79.6 wt.%) and γ-Fe2O3 as the secondary phase (20.4 wt.%), determined using the Rietveld refinement method. The presence of Fe2+ was attributed to oxygen vacancies. The mixed-phase α/γ-Fe2O3 catalyst exhibited remarkable photo-Fenton-like degradation performance for Rhodamine B (RhB) in neutral pH. The effects of operating parameters, including H2O2 concentration, catalyst concentration, and RhB concentration, on the degradation efficiency were investigated. The removal rates of color were 99.2% after 12 min at optimal conditions of photo-Fenton-like oxidation of RhB. The sample exhibited a high saturation magnetization of 28.6 emu/g. Additionally, the α/γ-Fe2O3 mixed-phase catalyst showed long-term stability during recycle experiments, with only a 5% decrease in activity.

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Section: Introductionmentioning

confidence: 78%

Magnetically Separable Mixed-Phase α/γ-Fe2O3 Catalyst for Photo-Fenton-like Oxidation of Rhodamine B

et al. 2023

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“…Meanwhile, we take into account the existence of Fe(OH) 3 in some samples, and it takes a suitable temperature to convert them into Fe 2 O 3 . 39 All the samples were annealed in air at 450 °C. XRD observations were used to research the chemical components and crystal structure of the precursor (NiC 2 O 4 ) and the prepared final products (Fe 2 O 3 @NiO).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The results correspond to expectations. Meanwhile, we take into account the existence of Fe(OH) 3 in some samples, and it takes a suitable temperature to convert them into Fe 2 O 3 . All the samples were annealed in air at 450 °C.…”

Section: Resultsmentioning

confidence: 99%

Hollow-Out Fe₂O₃-Loaded NiO Heterojunction Nanorods Enable Real-Time Exhaled Ethanol Monitoring under High Humidity

Zhou

et al. 2023

ACS Appl. Mater. Interfaces

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The analysis of exhaled breath has opened up new exciting avenues in medical diagnostics, sleep monitoring, and drunk driving detection. Nevertheless, the detection accuracy is greatly affected due to high humidity in the exhaled breath. Here, we propose a regulation method to solve the problem of humidity adaptability in the ethanol-monitoring process by building a heterojunction and hollow-out nanostructure. Therefore, large specific surface area hollow-out Fe2O3-loaded NiO heterojunction nanorods assembled by porous ultrathin nanosheets were prepared by a well-tailored interface reaction. The excellent response (51.2 toward 10 ppm ethanol at 80% relative humidity) and selectivity to ethanol under high relative humidity with a lower operating temperature (150 °C) were obtained, and the detection limit was as low as 0.5 ppb with excellent long-term stability. The superior gas-sensing performance was attributed to the high surface activity of the heterojunction and hollow-out nanostructure. More importantly, GC–MS, diffuse reflectance Fourier transform infrared spectroscopy, and DFT were utilized to analyze the mechanisms of heterojunction sensitization, ethanol-sensing reaction, and high-humidity adaptability. Our integrated low-power MEMS Internet of Things (IoT) system based on Fe2O3@NiO successfully demonstrates the functional verification of ethanol detection in human exhalation, and the integrated voice alarm and IoT positioning functions are expected to solve the problem of real-time monitoring and rapid initial screening of drunk driving. Overall, this novel method plays a vital role in areas such as control of material morphology and composition, breath analysis, gas-sensing mechanism research, and artificial olfaction.

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“…Generally, S and W line shape parameters, which describe the width of the annihilation spectrum, are used to obtain qualitative information about the electronic structure of solids 5 . As shown in Figure 1, parameters S and W are respectively defined as the ratio of the area of the central part of the spectrum (small linear momentum) and the ratio of the area of the areas with high momentum (tail of the spectrum or areas far from the center of the spectrum) to the total area of the CDBS spectrum 6 . Another method of CDBS spectrum analysis is to consider spectral data in the form of normalized count ratio in each channel to their corresponding number in the reference sample spectrum.…”

Section: Methodsmentioning

confidence: 99%

Characterization of polar groups in polyvinyl chloride–ethyl vinyl acetate blends using coincidence Doppler broadening spectroscopy

Ghasemifard,

Ghamari

2023

J of Applied Polymer Sci

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Coincidence Doppler broadening spectroscopy (CDBS), known for its exceptional precision, is extensively employed in examining the electronic states of polymers. In this study, polyvinyl chloride (PVC)–ethyl vinyl acetate (EVA) polymers blends were prepared using conventional techniques, following specific ratios (75:25, 50:50, and 25:75, respectively). Spectroscopic analysis reveals that the longitudinal component of linear momentum surpasses the momentum unit (i.e., 10−3 m0c) when considering the ratio curve associated with the participation of oxygen core electrons. When compared to non‐polymer samples, the PVA polymer and PVA–EVA polymer blend exhibit greater free volume voids in contrast to non‐polymer structural defects. Furthermore, the annihilation of ortho‐positronium with core electrons, likely EVA oxygen core electrons, contributes to the measured free volume voids. An increased annihilation of positrons or positroniums by oxygen in the CDBS spectrum leads to higher calculated W parameter values. Conversely, as the PVC content increases, the W parameter decreases, suggesting reduced ortho‐positronium annihilation and consequently, enhanced formation of para‐positronium in the overall annihilation process. In summary, this investigation demonstrates the utility of CDBS in elucidating the electronic states and free volume voids in PVC and EVA polymers.

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Synthesis of Porous Network-Like α-Fe2O3 and α/γ-Fe2O3 Nanoparticles and Investigation of Their Photocatalytic Properties

Cited by 6 publications

References 27 publications

Magnetically Separable Mixed-Phase α/γ-Fe2O3 Catalyst for Photo-Fenton-like Oxidation of Rhodamine B

Magnetically Separable Mixed-Phase α/γ-Fe2O3 Catalyst for Photo-Fenton-like Oxidation of Rhodamine B

Hollow-Out Fe₂O₃-Loaded NiO Heterojunction Nanorods Enable Real-Time Exhaled Ethanol Monitoring under High Humidity

Characterization of polar groups in polyvinyl chloride–ethyl vinyl acetate blends using coincidence Doppler broadening spectroscopy

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Synthesis of Porous Network-Like α-Fe2O3 and α/γ-Fe2O3 Nanoparticles and Investigation of Their Photocatalytic Properties

Cited by 6 publications

References 27 publications

Magnetically Separable Mixed-Phase α/γ-Fe2O3 Catalyst for Photo-Fenton-like Oxidation of Rhodamine B

Magnetically Separable Mixed-Phase α/γ-Fe2O3 Catalyst for Photo-Fenton-like Oxidation of Rhodamine B

Hollow-Out Fe2O3-Loaded NiO Heterojunction Nanorods Enable Real-Time Exhaled Ethanol Monitoring under High Humidity

Characterization of polar groups in polyvinyl chloride–ethyl vinyl acetate blends using coincidence Doppler broadening spectroscopy

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Product

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Hollow-Out Fe₂O₃-Loaded NiO Heterojunction Nanorods Enable Real-Time Exhaled Ethanol Monitoring under High Humidity