Structural and Magnetic Properties of Co Doped CeO$_{2}$ Nano-Particles

Kumar, Shalendra; Kim, Y.J.; Koo, Bon Heun; Choi, Heekyu; Lee, Chan Gyu

doi:10.1109/tmag.2009.2018602

Cited by 27 publications

(7 citation statements)

References 14 publications

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“…This decrease in oxygen occupancy is related to an increase in the content of oxygen vacancies in the ceria matrix to preserve electron neutrality, as proposed elsewhere [32]. The decrease in the lattice parameter of ceria-supported cobalt samples has been associated with the substitution of bigger Ce 4þ ion (radii ¼ 0.97 Å) by the smaller Co 2þ ion (radii ¼ 0.90 Å) or Co 3þ ion (radii ¼ 0.61 Å) [33,34]. The increase in lattice constant is explained in terms of strains in the lattice generated by an increasing molar fraction of oxygen vacancies [35].…”

Section: Sample Characterizationsupporting

confidence: 53%

Preparation, structural characterization and catalytic properties of Co/CeO2 catalysts for the steam reforming of ethanol and hydrogen production

Lovón

Lovón-Quintana

Almerindo

et al. 2012

Journal of Power Sources

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h i g h l i g h t s < Ceria-supported cobalt catalysts, with different cobalt contents, were prepared by the polymeric precursor method. < The catalysts were evaluated for the steam reforming of ethanol for hydrogen production. < The cobalt content of the catalyst influences the metal-support interaction which results in distinct catalyst performances. < The catalyst with the highest cobalt content showed the best performance among the catalysts tested. a b s t r a c tIn this paper, Co/CeO 2 catalysts, with different cobalt contents were prepared by the polymeric precursor method and were evaluated for the steam reforming of ethanol. The catalysts were characterized by N 2 physisorption (BET method), X-ray diffraction (XRD), UVevisible diffuse reflectance, temperature programmed reduction analysis (TPR) and field emission scanning electron microscopy (FEG-SEM). It was observed that the catalytic behavior could be influenced by the experimental conditions and the nature of the catalyst employed. Physicalechemical characterizations revealed that the cobalt content of the catalyst influences the metal-support interaction which results in distinct catalyst performances. The catalyst with the highest cobalt content showed the best performance among the catalysts tested, exhibiting complete ethanol conversion, hydrogen selectivity close to 66% and good stability at a reaction temperature of 600 C.

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Section: Sample Characterizationsupporting

confidence: 53%

Preparation, structural characterization and catalytic properties of Co/CeO2 catalysts for the steam reforming of ethanol and hydrogen production

Lovón

Lovón-Quintana

Almerindo

et al. 2012

Journal of Power Sources

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“…They found that 4% Ni doped CeO 2 sample exhibits a maximum value of saturation magnetization $1.21m emu/g and coercive field in the 40-120 Oe range. Previously, we have also reported weak ferromagnetism in TM (Fe, Co, Ni) doped CeO 2 nanoparticles [9][10][11]17]. Furthermore, we can say that the observed ferromagnetism in Ce 1Àx Mn x O 2 (0.0 x 0.10) nanoparticles may be intrinsic because it is very easy to rule out any impurity cause for the magnetic signal in Ce 1Àx Mn x O 2 (0.0 x 0.10) nanoparticles.…”

Section: Resultsmentioning

confidence: 65%

Signature of room temperature ferromagnetism in Mn doped CeO2 nanoparticles

Kumar

Anwar

Choi

et al. 2012

Materials Research Bulletin

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“…Some authors showed that Co-doped CeO 2 thin films present intrinsic ferromagnetic properties at room temperature [18][19][20][21] while others suggested in similar films, grown using the same techniques, that the magnetic properties are due to Co clusters. 22,23 In powder form, the same discrepancy exists as both intrinsic FM 24,25 and extrinsic FM due to Co clusters 26 were reported. Note that in all the studies claiming intrinsic FM, the non-observation of clusters and spurious phases is mainly supported by X-ray diffraction and high resolution transmission electron microscopy.…”

Section: Introductionmentioning

confidence: 74%

High-temperature ferromagnetism in Co-doped CeO2 synthesized by the coprecipitation technique

Colis

Bouaine

Schmerber

et al. 2012

Phys. Chem. Chem. Phys.

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The aim of the present study is to check the influence of annealing under vacuum and a mixture of N(2)-H(2) atmosphere on the magnetic properties of polycrystalline Co-doped CeO(2) diluted magnetic oxides (DMOs) with Co concentrations of 5 at% synthesized using the coprecipitation technique. X-Ray diffraction (XRD) patterns and transmission electron microscopy (TEM) showed for all samples the expected CeO(2) cubic fluorite-type structure and that Co ions are uniformly distributed inside the samples. Room-temperature Raman and photoluminescence (PL) spectroscopies indicate an increase in the concentration of oxygen vacancies upon Co doping and further annealing. Field dependent magnetization measurements revealed a paramagnetic behavior for as-prepared Co-doped CeO(2), while a ferromagnetic behavior appears when the same samples are annealed under vacuum or N(2)-H(2) atmosphere. Temperature dependent magnetization measurements suggest that the observed ferromagnetism is due to the presence of metallic Co clusters with nanometric size and broad size distribution. These results are supported by electron paramagnetic resonance studies.

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Structural and Magnetic Properties of Co Doped CeO$_{2}$ Nano-Particles

Cited by 27 publications

References 14 publications

Preparation, structural characterization and catalytic properties of Co/CeO2 catalysts for the steam reforming of ethanol and hydrogen production

Preparation, structural characterization and catalytic properties of Co/CeO2 catalysts for the steam reforming of ethanol and hydrogen production

Signature of room temperature ferromagnetism in Mn doped CeO2 nanoparticles

High-temperature ferromagnetism in Co-doped CeO2 synthesized by the coprecipitation technique

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