Spectroscopic characterization of iron bismuth (antimony/tantalum) pyrochlores synthesized by the molten salts method

León-Flores, J.; Pérez-Mazariego, J.L.; Flores-Morales, S.S.; Hinojosa, Roberto Andrés González; Arévalo-López, E.P.; Escamilla, R.; Gómez, R.

doi:10.1016/j.ceramint.2021.08.084

Cited by 5 publications

(3 citation statements)

References 30 publications

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“…The commercial ZnO NPs binding energy region is in good concordance with those values reported in NIST [69] 1044.7 eV (2p 1/2 ) and 1021.5 eV (2p 3/2 ). However, for the black ZnO NPs in the 2p core-level region it is observed the presence of a small shift into higher energies; compared against the commercial zinc oxide nanoparticles, and being indicative of an electronic density redistribution around the Zn atoms [70][71][72] supporting the assumption of vacancies in the black ZnO, as HRTEM results suggested and as it was previously reported in similar works for black ZnO [42,48,49].…”

Section: Resultssupporting

confidence: 71%

Black ZnO nanoparticles synthesized by a green chemistry process

León-Flores,

Melo-Uscanga,

Pérez-Mazariego

et al. 2024

Nano Ex.

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The green chemistry synthesis has acquired importance in recent years because of the avoidance of hazardous byproducts. In the present work, black ZnO nanoparticles were synthesized by a combustion green chemistry process using coffee extract as a reducer agent and stabilizer of the reaction. The preponderance size distribution of the black ZnO nanoparticles was found between 15 and 30 nm. High-resolution transmission electron microscopy shows distorted regions from the atomic column, while the estimated energy band gap measured by UV-Vis spectroscopy is 2.22 eV, which is a 30% value below the typical band gap for bulk ZnO. XPS measurements display a shift in the binding energy of the black ZnO compared against commercial ZnO. From the experimental evidence, it is proposed that the black color of the zinc oxide was a consequence of vacancies in the ZnO structure. Vacancies in the structure were modeled theoretically by considering a variation in the Coulomb interaction between Zn – O atoms by applying the Hubbard + U DFT approximation. The theoretical electronic distribution of the vacant ZnO was compared with experimental results obtained by Raman, FTIR and the experimental profile of the valence band region. These results open the exploration of green synthesized black zinc oxide nanoparticles to many technological applications.

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Section: Resultssupporting

confidence: 71%

Black ZnO nanoparticles synthesized by a green chemistry process

León-Flores,

Melo-Uscanga,

Pérez-Mazariego

et al. 2024

Nano Ex.

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“…In recent years, the need of cleaner and sustainable methodologies or the socalled green chemistry methods aim to avoid or diminish the waste reagents production after chemical reactions. The Molten Salts Method (MSM) is an alternative route for the synthesis of complex oxide materials which has been successfully tested for the formation of perovskite, sillenite and pyrochlore compounds [14][15][16][17][18][19] which also offers a high scalable material production. The synthesis process uses a mixture of convenient salts as a reaction media for the constituent metal oxide precursors that enhance time-saving formation process; therefore, the products achieved after the reaction are the complex oxide material and saline water [14].…”

Section: Introductionmentioning

confidence: 99%

Firing salts method for the synthesis of orthorhombic Gd₂TiO₅: experimental characterization supported by DFT first principles calculations

Quintana-García,

León-Flores,

Pérez-Mazariego

et al. 2024

Mater. Res. Express

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This work presents the synthesis by the new “firing salts method” (FSM) of orthorhombic Gd2TiO5 which requires only two hours at 1200 ºC. X Ray Diffraction, High Resolution Transmission Electron Microscopy, Fourier Transform Infrared Spectroscopy and Raman spectroscopy characterized it. Electron microscopy shows particle size distribution between 50 – 500 nm with orthorhombic structure according to Rietveld analysis. Raman – infrared spectroscopies and first principles calculations indicate that the second order contribution to the spectra comes from the Ti-O5 interactions. First principles calculations (Density Functional Theory) were used as an aid for the interpretation of the experimental results to assign the normal modes to the bands on the Raman and IR spectra; it also provided an insight of the chemical reactivity of the synthesis.

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“…However, using nickel ferrite for technological purposes requires low-cost and highly scalable production methods with a reduction of waste reagents. The molten salts synthesis is a green chemistry approach [15], which has been successfully tested in the formation of complex oxides [16][17][18][19][20][21] comprising the combination of simple oxide reagents in the desired stoichiometry into an adequate proportion of salts that entails a time-saving and highly scalable synthesis process, with non-toxic reagents involved since the by-product after the reaction process is saline water.…”

Section: Introductionmentioning

confidence: 99%

Rapid synthesis of nickel ferrite nanoparticles by the molten salt method

León-Flores,

Pérez-Mazariego,

Olmedo-Reséndiz

et al. 2023

Mater. Res. Express

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It is presented a “shocking thermal treatment” methodology as a modification to the molten salts process to rapidly obtain pure phase nickel ferrite nanoparticles within a high-scalable green synthesis scheme. Analysis from X-ray diffraction and electron microscopy (SEM and TEM) confirms the formation of the nanostructures, with the most frequent crystallite sizes between 55-85 nm. Room temperature magnetic characterization, from Mössbauer spectroscopy and magnetic measurements M(H), evidences their superparamagnetic distribution with a magnetic saturation of 47.9 emu/g. An approximated stoichiometry of (Ni0.03 Fe0.97)A (Ni0.97Fe1.03)BO4 was proposed from Rietveld refinement, Mössbauer and energy-dispersive X-ray spectroscopies. The effect on the electronic structure due to the shocking thermal treatment was elucidated by estimating the optical band gap with values between 1.78 and 2.38 eV.

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Spectroscopic characterization of iron bismuth (antimony/tantalum) pyrochlores synthesized by the molten salts method

Cited by 5 publications

References 30 publications

Black ZnO nanoparticles synthesized by a green chemistry process

Black ZnO nanoparticles synthesized by a green chemistry process

Firing salts method for the synthesis of orthorhombic Gd₂TiO₅: experimental characterization supported by DFT first principles calculations

Rapid synthesis of nickel ferrite nanoparticles by the molten salt method

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Spectroscopic characterization of iron bismuth (antimony/tantalum) pyrochlores synthesized by the molten salts method

Cited by 5 publications

References 30 publications

Black ZnO nanoparticles synthesized by a green chemistry process

Black ZnO nanoparticles synthesized by a green chemistry process

Firing salts method for the synthesis of orthorhombic Gd2TiO5: experimental characterization supported by DFT first principles calculations

Rapid synthesis of nickel ferrite nanoparticles by the molten salt method

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Product

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Firing salts method for the synthesis of orthorhombic Gd₂TiO₅: experimental characterization supported by DFT first principles calculations