Magnetic and dielectric properties of carbon nanotubes with embedded cobalt nanoparticles

Andreev, A. F.; Kazakova, Мariya A.; Ищенко, А. В.; Selyutin, Alexander G.; Lapina, Olga B.; Кузнецов, Владимир Л.; Lacaillerie, Jean-Baptiste d’Espinose de

doi:10.1016/j.carbon.2016.11.070

Cited by 48 publications

(36 citation statements)

References 69 publications

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“…Co, Fe, and Co/Fe‐oxide/MWCNT samples were prepared by incipient wet impregnation of oxidized MWCNTs with aqueous solutions of cobalt(II) and iron(III) nitrates . After impregnation for 12 h, the products were dried at 110 °C for 4 h followed by calcination at 350 °C for 4 h under an argon atmosphere.…”

Section: Methodssupporting

confidence: 91%

“…To obtain mono‐ or bimetallic (Fe/Co) oxide nanoparticles supported on oxidized multiwalled carbon nanotubes, with various Fe/Co ratios, the wet impregnation technique was used . The concentration of the initial iron and cobalt nitrate solution was varied to obtain samples with a total metal loading of approximately 13.5 wt % and different Fe/Co ratios.…”

Section: Resultsmentioning

confidence: 99%

“…It is therefore expected that the deposition happens via wall defects. This means the metal cations of the initial impregnation solution penetrate through the wall defects into the tube channels, presumably by capillary forces . Analysis of the HRTEM images (Figure a–f) clearly reveals that for all the characterized samples, whether monometallic (Co or Fe) or mixed Fe/Co oxides, two ensembles of predominantly spherical nanoparticles of different average diameters localized inside and outside (on the surface) of the MWCNTs were formed.…”

Section: Resultsmentioning

confidence: 99%

“…Investigations of morphology,structure, particle localization, and chemical state of the Fe/Co/MWCNT catalysts To obtain mono-o rb imetallic (Fe/Co) oxide nanoparticles supported on oxidized multiwalled carbon nanotubes, with variousF e/Co ratios, the wet impregnationt echnique was used. [26,27] The concentrationo ft he initial iron and cobalt nitrates olution was varied to obtain samples with at otal metal loading of approximately 13.5 wt %a nd different Fe/Co ChemSusChem 2018ChemSusChem , 11,1204ChemSusChem -1214 www.chemsuschem.org ratios. Ab atch of 13 samples with the general composition Fe x Co 1Àx /MWCNT with x = 1, 0.99, 0.95, 0.9, 0.7, 0.6, 0.5, 0.4, 0.3, 0.1, 0.05, 0.01, and 0w as synthesized to study the dependence of the ORR/OER bifunctional activity on the catalyst composition.…”

Section: Resultsmentioning

confidence: 99%

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Bifunctional Oxygen Reduction/Oxygen Evolution Activity of Mixed Fe/Co Oxide Nanoparticles with Variable Fe/Co Ratios Supported on Multiwalled Carbon Nanotubes

et al. 2018

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A facile strategy is reported for the synthesis of Fe/Co mixed metal oxide nanoparticles supported on, and embedded inside, high purity oxidized multiwalled carbon nanotubes (MWCNTs) of narrow diameter distribution as effective bifunctional catalysts able to reversibly drive the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) in alkaline solutions. Variation of the Fe/Co ratio resulted in a pronounced trend in the bifunctional ORR/OER activity. Controlled synthesis and in-depth characterization enabled the identification of an optimal Fe/Co composition, which afforded a low OER/OER reversible overvoltage of only 0.831 V, taking the OER at 10 mA cm and the ORR at -1 mA cm . Importantly, the optimal catalyst with a Fe/Co ratio of 2:3 exhibited very promising long-term stability with no evident change in the potential for both the ORR and the OER after 400 charge/discharge (OER/ORR) cycles at 15 mA cm in 6 m KOH. Moreover, detailed investigation of the structure, size, and phase composition of the mixed Fe/Co oxide nanoparticles, as well as their localization (inside of or on the surface of the MWCNTs) revealed insight of the possible contribution of the individual catalyst components and their synergistic interaction in the catalysis.

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Section: Methodssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Bifunctional Oxygen Reduction/Oxygen Evolution Activity of Mixed Fe/Co Oxide Nanoparticles with Variable Fe/Co Ratios Supported on Multiwalled Carbon Nanotubes

et al. 2018

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“…31 Mg-containing samples were prepared by impregnation of functionalized MWNTs with the aqueous solutions of magnesium nitrate (MgĲNO 3 ) 2 ·6H 2 O, 98%, Vekton). 32 After impregnation for 6 h the samples were dried at 110°C for 4 hours followed by calcination at 350°C for 4 hours under argon. By varying the concentration of the magnesium nitrate solutions, samples of 5 and 20 wt% Mg loadings were obtained.…”

Section: Catalystsmentioning

confidence: 99%

Aldose to ketose interconversion: galactose and arabinose isomerization over heterogeneous catalysts

Murzin

Murzina

Aho

et al. 2017

Catal. Sci. Technol.

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Isomerization of glucose, galactose and arabinose to corresponding keto-sugars was studied in the present work over a range of heterogeneous catalysts. Magnesium aluminates with different ratios between oxides resulting in materials with a Mg/Al ratio from 0.2 to 0.9 were prepared, characterized and evaluated in terms of their catalytic behavior. The catalyst with a Mg/Al ratio close to hydrotalcites was the most efficient considering activity, selectivity and stability. The sugar structure was shown to have a minor influence on catalytic activity and selectivity.

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Fe–Mo and Co–Mo Catalysts with Varying Composition for Multi‐Walled Carbon Nanotube Growth

Kazakova

Кузнецов

Bokova‐Sirosh

et al. 2017

Physica Status Solidi (b)

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The formation of active component of Fe-Mo and Co-Mo catalysts for carbon nanotube growth with variable Mo content is studied with in situ XRD, XPS, and STEM&EDX. The activation of bimetallic Fe-Mo catalysts under the growth conditions leads to the formation of Fe-Mo alloy particles in contrast to Co-containing catalysts in which active alloy incorporates only a small portion of Mo (<2-3 at.%). The stable carbide formation for these systems is not detected. The effect of Mo content in Fe-Mo and Co-Mo catalysts on the properties of MWCNTs is additionally investigated using the Raman spectroscopy in combination with measurements of the temperature dependence of conductivity. It is shown that MWCNT defectiveness depends on the active component composition for both Fe-Mo and Co-Mo catalysts. The current carrier concentration for the MWCNTs grown on Fe-Mo catalysts slightly increases with the Mo content. The opposite effect is observed for the tubes grown on Co-Mo catalysts, showing a decrease in the current carrier concentration with the increase of Mo concentration.

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Magnetic and dielectric properties of carbon nanotubes with embedded cobalt nanoparticles

Cited by 48 publications

References 69 publications

Bifunctional Oxygen Reduction/Oxygen Evolution Activity of Mixed Fe/Co Oxide Nanoparticles with Variable Fe/Co Ratios Supported on Multiwalled Carbon Nanotubes

Bifunctional Oxygen Reduction/Oxygen Evolution Activity of Mixed Fe/Co Oxide Nanoparticles with Variable Fe/Co Ratios Supported on Multiwalled Carbon Nanotubes

Aldose to ketose interconversion: galactose and arabinose isomerization over heterogeneous catalysts

Fe–Mo and Co–Mo Catalysts with Varying Composition for Multi‐Walled Carbon Nanotube Growth

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