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2.
R Soc Open Sci ; 4(6): 170273, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28680680

RESUMO

The current communication signifies the effect of oxygen vacancies (OVs) both qualitatively and quantitatively in multiferroic BiFe0.83Ni0.17O3 by an in-depth atomic-level investigation of its electronic structure and magnetization properties, and these materials have a variety of applications in spintronics, optoelectronics, sensors and solar energy devices. Depending on the precise location of OVs, all the three types of spintronic material namely half-metallic, spin gapless semiconductor and bipolar magnetic conductor have been established in a single material for the first time and both super-exchange and double-exchange interactions are possible in accordance with the precise location of OVs. We have also calculated the vacancy formation energies to predict their thermodynamic stabilities. These results can highlight the impact and importance of OVs that can alter the multiferroic properties of materials.

3.
J Photochem Photobiol B ; 165: 121-132, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27776260

RESUMO

The present work describes the successful synthesize of spinel magnetic ferrite Mn1-xNixFe2O4 (x=0.0, 0.1, 0.2, 0.3, 0.4 & 0.5) nanoparticles via a simple microwave combustion method which was then evaluated for its photocatalytic activity in the degradation of indigo carmine (IC) synthetic dye, a major water pollutant. Our results reveal that the synthesized of Ni2+ doped MnFe2O4 nanoparticles possess well-crystalline pure cubic spinel phase, exhibit excellent optical and magnetic properties. Further, the photocatalytic performance of the synthesized nanoparticles at different concentration ratios of Ni2+ ions was monitored by photocatalytic degradation of indigo carmine synthetic dye under UV (λ=365nm) light irradiation. In order to get maximum photocatalytic degradation (PCD) efficiency, we have optimized various parameters, which include catalyst dosage, initial dye concentration, pH and Ni2+ dopant content. It was found that the reaction was facilitated with optimum catalyst dose of 50mg/100mL, high dye concentrations of 150mg/L and acidic pH and among all the synthesized samples, Mn0·5Ni0.5Fe2O4 exhibit superior performance of photocatalytic activity on the degradation of indigo carmine synthetic dye. These results highlighted the potential use of effective, low-cost and easily available photocatalysts for the promotion of wastewater treatment and environmental remediation. In addition, the antibacterial activity of spinel magnetic Mn1-xNixFe2O4 nanoparticles against two Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram negative bacteria (Pseudomonas aeruginosa and Escherichia coli) was also examined. Our antibacterial activity results are comparable with the results obtained using the antibiotic, streptomycin.


Assuntos
Antibacterianos/farmacologia , Nanopartículas Metálicas/química , Fotólise , Antibacterianos/química , Bactérias/efeitos dos fármacos , Cristalografia por Raios X , Luminescência , Magnetismo , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Difração de Raios X
4.
J Nanosci Nanotechnol ; 15(8): 5910-7, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26369171

RESUMO

Pure and M-doped (Ba, Ce, Mg) ZnO spherical nanoparticles are synthesized by a simple low temperature co-precipitation method, and were characterized by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), and high resolution transmission electron microscopy (HR-TEM). The XRD results showed the formation of single phase ZnO with wurtzite crystal structure and the electron microscopic studies supported the validity for the formation of pure and M-doped (Ba, Ce, Mg) ZnO spherical nanoparticles. Photocatalytic degradation (PCD) of 2,4,6-trichlorophenol, a potent endocrine disrupting chemical in aqueous medium was investigated by both pure and M-doped (Ba, Ce, Mg) ZnO spherical nanoparticles under UV-light irradiation. The influence of the metal dopants on the structure and photocatalytic (PC) activity of ZnO was investigated systematically. Furthermore, the effect of different parameters such as 2,4,6-trichlorophenol concentration, photocatalyst amount, pH and dopant wt% on the resulting PC activity was investigated. The kinetics of the photocatalytic degradation of 2,4,6-trichlorophenol was found to follow the pseudo-first order reaction, and it was established that Ba-doped ZnO is photocatalytically more active than the other photocatalysts.

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