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Author: search.filters.author.Tangcharoen, ThanitSubject: search.filters.subject.Sol-gel auto-combustion

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    Synchrotron X-ray absorption spectroscopy study of disordered cation distribution of nanosized zinc ferrite powders
    (2016-01-01)
    Tangcharoen, Thanit
    ;
    Kongmark, Chanapa
    ;
    Klysubun, Wantana
    ;
    Pecharapa, Wisanu
    The zinc ferrite (ZnFe<inf>2</inf>O<inf>4</inf>) powders of various nanoparticle sizes were synthesised at different milling times (0 to 24 h) of the as-combusted powders. The non-equilibrium site occupancy of zinc (Zn<sup>2+</sup>) and ferric (Fe<sup>3+</sup>) ions was investigated through Zn and Fe K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra. The XRD and SEM strongly confirm the particle size of these ferrites decreasing with the increasing milling time. Compared with the bulk specimen of zinc ferrite, both XANES and EXAFS spectra of zinc ferrite powders clearly exhibit the large translocation of Zn<sup>2+</sup> ions from the tetrahedral (A) sites to the octahedral (B) sites and the opposite translocation of some of Fe3+ ions without affecting the long-range structural order. Moreover, the curve-fitting analysis of Zn and Fe K-edge EXAFS spectra indicates that the degree of inversion increases as the particle size decreases resulting in significant differences in the magnetic behaviours.
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    Characterization and enhanced photocatalytic performance of nanocrystalline Ni-substituted Zn ferrites synthesized by DEA-assisted sol-gel auto-combustion method
    (2013-06-01)
    Tangcharoen, Thanit
    ;
    Ruangphanit, Anucha
    ;
    Klysubun, Wantana
    ;
    Pecharapa, Wisanu
    Nanocrystalline Ni-substituted Zn ferrites with compositions of Ni <inf>x</inf>Zn<inf>1-x</inf>Fe<inf>2</inf>O<inf>4</inf> (x = 0-1.0) were synthesized by sol-gel auto-combustion method using metal nitrate as the reactants. Diethanolamine was selected as the fuel instead of conventional fuels such as urea, citric acid, tartaric acid or glycine. Characterization of after-calcined ferrite samples were conducted in terms of crystal structure, molecular vibrations, morphology and magnetic properties through X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and vibrating sample magnetometer analysis, respectively. The photocatalytic activities of these ferrites were studied in term of degradation of Rhodamine B under daylight-irradiation. The corresponding results indicate that nickel loading content has significant effect on physical, magnetic, optical and photocatalytic properties of the ferrite. Comparing to the undoped Zn ferrite, Ni<inf>0.6</inf>Zn<inf>0.4</inf>Fe<inf>2</inf>O<inf>4</inf> shows the enhancement in photocatalytic activity accompanying the degradation of Rhodamine B aqueous solution up to 77 % within 4 h. The result suggests the feasibility of this material as potential sunlight-activated photocatalyst in wastewater treatment and environment cleaning applications. © 2013 Springer Science+Business Media New York.