Porous CoFe2 O4 /C NRAs supported on nickel foam@NC (denoted as NF@NC-CoFe2 O4 /C NRAs) are directly fabricated by the carbonization of bimetal-organic framework NRAs grown on NF@poly-aniline(PANI), and they exhibit high electrocatalytic activity, low overpotential, and high stability for the oxygen evolution reaction in alkaline media.

Bimetal-Organic Framework Derived CoFe2O4/C Porous Hybrid Nanorod Arrays as High-Performance Electrocatalysts for Oxygen Evolution Reaction

The role of cobalt ferrite magnetic nanoparticles in medical science

Highly ordered mesoporous copper ferrite (meso-CuFe2O4) with high surface area and large pore size was successfully fabricated and firstly proposed as a heterogeneous Fenton catalyst. It was synthesized through the nanocasting strategy by using KIT-6 as hard template. The morphology and physicochemical properties of meso-CuFe2O4 were characterized by SEM, TEM, XRD, XPS, FT-IR, Raman spectra, etc. The obtained results showed that the surface area and the pore size of meso-CuFe2O4 were 122 m2 g−1 and 9.2 nm, respectively. The meso-CuFe2O4 presented excellent catalytic activity for the degradation of imidacloprid, achieving almost complete removal of 10 mg L−1 imidacloprid after 5 h at the reaction conditions of 0.3 g L−1 catalyst and 40 mM H2O2. Kinetic analysis showed that the degradation of imidacloprid follows the pseudo-first order. The apparent rate constant for meso-CuFe2O4 was 1.0445 h−1, which was 1.5, 2 and 2.5 times than those of meso-CoFe2O4, con-CuFe2O4 and nano-Fe3O4, respectively. The amount of hydroxyl radical (OH) generated was directly proportional to the degradation efficiency of imidacloprid, suggesting the involvement of OH in oxidizing imidacloprid. The obtained results indicated that meso-CuFe2O4 presented the highest activity, which was not only due to its ordered mesoporous structure with high surface area and large pore size, but also assigned to the redox recycle of Fe2+/Fe3+ and Cu+/Cu2+ in meso-CuFe2O4. The special effect of Cu was discussed in terms of the thermodynamically favorable Fe3+ reduction by Cu+, regenerating the active species Fe2+. The meso-CuFe2O4 presented very low iron leaching (<1 ppm) even in acidic condition and retained almost its high catalytic activity after 5 consecutive runs. Besides, meso-CuFe2O4 possessed medium saturation magnetization, which had provided a potential advantage for the recovery and reuse of catalyst.

Magnetic ordered mesoporous copper ferrite as a heterogeneous Fenton catalyst for the degradation of imidacloprid

MOF-templated synthesis of CoFe2O4 nanocrystals and its coupling with peroxymonosulfate for degradation of bisphenol A.

CoFe2O4 magnetic nanoparticles as a highly active heterogeneous catalyst of oxone for the degradation of diclofenac in water

Cation distribution and particle size effect on Raman spectrum of CoFe2O4

Cobalt ferrite nanoparticles of different sizes are prepared by varying the concentration of Co2+ metal ions using precipitation approach. The average crystallite size, coercivity (HC), and saturation magnetization (MS) increases from 11 to 16 nm, 0.12 to 0.8 kOe, and 28 to 52 emu/g, respectively, as Co2+ ion concentration is reduced from 0.4 to 0.025 M. High resolution transmission electron microscopy and X-ray diffraction analysis confirms that CoFe2O4 nanoparticles are crystalline in nature with cubic structure. Raman spectroscopic investigation shows traces of paramagnetic ferrihydrite in samples prepared with Co2+ ion concentration greater than 0.1 M. These experimental results suggest that metal ion concentration plays an important role in the size, magnetic property and purity of precipitated cobalt ferrite nanoparticles. The variation in the average crystalline size with Co2+ ion concentration is in good agreement with the nucleation theory. Our approach is useful in tuning the size and magnetic p...

Influence of Co2+ Ion Concentration on the Size, Magnetic Properties, and Purity of CoFe2O4 Spinel Ferrite Nanoparticles

Cation distribution in NixMg1−xFe2O4 studied by XPS and Mössbauer spectroscopy

This article discusses aspects of biofouling and corrosion in the thermo-fluid heat exchanger (TFHX) and in the cooling water system of a nuclear test reactor. During inspection, it was observed that  >90% of the TFHX tube bundle was clogged with thick fouling deposits. Both X-ray diffraction and Mossbauer analyses of the fouling deposit demonstrated iron corrosion products. The exterior of the tubercle showed the presence of a calcium and magnesium carbonate mixture along with iron oxides. Raman spectroscopy analysis confirmed the presence of calcium carbonate scale in the calcite phase. The interior of the tubercle contained significant iron sulphide, magnetite and iron-oxy-hydroxide. A microbiological assay showed a considerable population of iron oxidizing bacteria and sulphate reducing bacteria (105 to 106 cfu g−1 of deposit). As the temperature of the TFHX is in the range of 45–50°C, the microbiota isolated/assayed from the fouling deposit are designated as thermo-tolerant bacteria. The mean corrosi...

P. Chandramohan

Papers

Cation distribution and particle size effect on Raman spectrum of CoFe2O4

Influence of Co2+ Ion Concentration on the Size, Magnetic Properties, and Purity of CoFe2O4 Spinel Ferrite Nanoparticles

Cation distribution in NixMg1−xFe2O4 studied by XPS and Mössbauer spectroscopy

Biofouling and microbial corrosion problem in the thermo-fluid heat exchanger and cooling water system of a nuclear test reactor.

Studies on the synthesis and characterization of cesium-containing iron phosphate glasses