Probing the local atomic structure in CoLa0.15Fe1.85O4 as a function of the synthesis method by multi edge XAFS

Imam, N.G.; Aquilanti, G.; Mansour, S.F.; Meneghini, Carlo

doi:10.1088/2053-1591/ab44e5

Cited by 12 publications

(5 citation statements)

References 26 publications

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“…10, shifted and arranged vertically according to their observed FT amplitudes. It is clear that the sample with x = 0.03R (R stands for after irradiation) shows the maximum FT amplitude, suggesting the highest coordination number of the surrounding atoms (Imam et al, 2019). On the contrary, the samples with x = 0.05 and 0.07 show the lowest values of FT amplitude, suggesting the lowest coordination number of the surrounding atoms around the Mn absorbers.…”

Section: Figurementioning

confidence: 94%

“…The obtained prepared powder samples were preliminary characterized using an X-ray diffractometer (ProkerD8-USA) with Cu K radiation (1.54056 A ˚) over a wide range of Bragg angle (from 20 to 80 ). To correct for XRD instrumental broadening, an XRD pattern of LaB 6 standard sample was collected (Imam et al, 2019). The magnetic properties were measured using a vibrating sample magnetometer (VSM) (Model 7410, Lakeshore, USA).…”

Section: Synthesis Procedures and Instrumentationmentioning

confidence: 99%

“…The necessity of the XAFS technique arises from monitoring the induced changes in the electronic and fine/ local structures around absorbing ions in the short-range order of a few angstroms ($ 5 A ˚). This structural change is difficult to monitor from direct X-ray diffraction (XRD) measurements, which determines the average crystal structure in the long-range order (Imam et al, 2019). Moreover, the XRD technique could not distinguish between different elements with similar scattering factors.…”

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confidence: 99%

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Coupling between γ-irradiation and synchrotron-radiation-based XAFS techniques for studying Mn-doped ZnO nanoparticles

Imam¹,

Harfouche²,

Azab³

et al. 2022

J Synchrotron Rad

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γ-Irradiation and synchrotron-radiation-based X-ray absorption fine-structure (XAFS) spectroscopy have been used to induce structure disorder through the interaction of γ-rays (200 kGy) with fabricated Mn-doped ZnO nanoparticles (NPs) and then to examine thoroughly the resultant structural change. The extracted electronic/fine XAFS structural parameters reflect a compositional and γ-irradiation co-dependence. The average crystal structure of samples prepared by the sol-gel method was investigated by X-ray diffraction (XRD). A detailed structural XRD data analysis was carried out by applying a Rietveld refinement using the MAUD program. XAFS spectra were collected at the Zn K-edge (9659 eV) in transmission mode and at the Mn K-edge (6539 eV) in fluorescence mode. Direct evidence of the solubility of Mn ions in the ZnO structure was demonstrated by fitting the extended-XAFS (EXAFS) signal. Near-edge XAFS (XANES) analysis provided the oxidation states of Zn and Mn ions through fingerprint XANES spectra of the sample along with those of standard compounds. Linear combination fitting showed that the most fit chemical forms of Zn and Mn in the samples are ZnO and MnO, respectively. The oxidation states of both Zn and Mn XAFS absorbers were confirmed from pre-edge fitting. The results of the magnetic measurements were explained in light of the average and electronic/local structural information obtained from XRD, XANES and EXAFS techniques. The magnetic properties of the samples translate into an induced change in the average crystal and electronic/local structures upon Mn concentration change and γ-irradiation. XRD confirmed the successful preparation of hexagonal Mn-doped ZnO NPs with a crystallite size in the range 33–41 nm. Both XRD and EXAFS analysis detected a minor amount of Mn3O4 as a secondary phase. XANES and EXAFS provided information exploring the outstanding potential of the utilized protocol for detecting precisely the presence of the secondary phase of Mn3O4, which changes with Mn content (x). Mean-square relative displacement (σ2) values extracted from the EXAFS fitting were found to grow for Zn–Zn/Mn paths demonstrating the substitution of Mn/Zn into Zn crystal sites. The EXAFS analysis explains the reasons behind the enhancement in the magnetic properties and shows that the Mn doping content at x = 0.05 produces the most local atomic disorder in ZnO NPs. There is a strong harmony among the XRD, XANES, EXAFS and magnetization behavior of the Mn-doped ZnO NPs. Maximum magnetization was acquired at an Mn content of 0.05. γ-Ray-irradiated Zn1–x Mn x O NPs are recommended as optimized candidates for showing the diversity of the applications.

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Section: Figurementioning

confidence: 94%

Section: Synthesis Procedures and Instrumentationmentioning

confidence: 99%

mentioning

confidence: 99%

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Coupling between γ-irradiation and synchrotron-radiation-based XAFS techniques for studying Mn-doped ZnO nanoparticles

Imam¹,

Harfouche²,

Azab³

et al. 2022

J Synchrotron Rad

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“…The high brilliance provided by synchrotron radiation (SR) allows one to study materials where the contaminants (e.g. Pb and Ni) are highly diluted (Imam et al, 2019). Furthermore, the chemical selectivity of XANES allows one to investigate the elements of interest within a matrix (Wang et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Heavy metals concentrations and speciation of Pb and Ni in airborne particulate matter over two residential sites in Greater Cairo – reflection from synchrotron radiation

et al. 2022

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Synchrotron radiation-based techniques [X-ray absorption near-edge structure (XANES) and X-ray fluorescence (XRF)] combined with inductively coupled plasma-mass spectrometry (ICP-MS) were used for the assessment of heavy metals concentrations as well as lead (Pb) and nickel (Ni) speciation in airborne particulate matter (PM10) over two residential sites in Greater Cairo. Nineteen 24 h high-volume samples collected at Giza (G) Square and Helwan (H) University (Egypt) were selected for this study. Mean concentrations of heavy metals in PM10 at both sites were found to have the same descending order of Pb > Cu > Ni > Cd > Co > As, of which concentrations of Pb, Cu, Ni and Cd in H samples were higher than those in G samples. For Pb, synchrotron-based XRF results were in good agreement with concentrations obtained by ICP-MS. The XANES spectra of PM10 at the Pb L 2-edge and Ni K-edge were compared with those of Pb and Ni in model standard compounds to provide information on the potential oxidation states as well as the chemical forms of those elements. The data show that Pb has similar chemical environments in both series G and H with the predominance of Pb2+ oxidation state. Nickel was found as Ni(OH)2, NiO and Ni metal in the analyzed samples. However, the content of Ni in the background filter shows a very strong interference with that of the collected PM10. Carcinogenic and non-carcinogenic risks resulting from the inhalation of the studied heavy metals were assessed for children and adult residents and were found below the safe limits, at both sites.

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“…These unique features make XAFS the perfect tool for gaining physical insights into the reaction mechanism. In fact, XAFS has gradually become a routine and expected characterization technique in the field of catalysis among others [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

X-ray absorption fine structure measurements on Ru–Zn/ZSM-5 during heterogeneous catalysis using an in situ spectroscopic cell

Liu¹,

He²,

Xia³

et al. 2020

Electron. Struct.

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We introduce a design of a portable, multi-functional spectroscopic cell for in situ structural probe of materials using hard x-rays. This versatile reaction cell allows x-ray absorption fine structure (XAFS) and x-ray diffraction measurements in transmission mode on solids at a controlled temperature, pressure, and gas environment. A model heterogeneous catalysis system, co-aromatization of octane with methane catalyzed by Ru–Zn/ZSM-5, was employed to demonstrate the performance of the spectroscopic cell. Quick XAFS measurement at the Ru K-edge was performed during the catalyst activation and catalysis reaction. The chemical reduction of Ru from RuO2 to metallic-like Ru is found to occur rapidly once the temperature is above a threshold, and the reduction is completed in ∼75 s. Prolonged heating during catalysis reaction at constant operating temperature has a minimum effect on the electronic structure of the Ru species.

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Probing the local atomic structure in CoLa_0.15Fe_1.85O₄ as a function of the synthesis method by multi edge XAFS

Cited by 12 publications

References 26 publications

Coupling between γ-irradiation and synchrotron-radiation-based XAFS techniques for studying Mn-doped ZnO nanoparticles

Coupling between γ-irradiation and synchrotron-radiation-based XAFS techniques for studying Mn-doped ZnO nanoparticles

Heavy metals concentrations and speciation of Pb and Ni in airborne particulate matter over two residential sites in Greater Cairo – reflection from synchrotron radiation

X-ray absorption fine structure measurements on Ru–Zn/ZSM-5 during heterogeneous catalysis using an in situ spectroscopic cell

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