Oxygen vacancy and Ce3+ ion dependent magnetism of monocrystal CeO2 nanopoles synthesized by a facile hydrothermal method

Wang, Leini; Meng, Fanning

doi:10.1016/j.materresbull.2013.05.036

Cited by 158 publications

(53 citation statements)

References 46 publications

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“…7 the observed RT-FM in undoped CeO 2 resulted from exchange interactions between Ce 3+ and V O according to the FCE mechanism. Similar behavior has also been reported for CeO 2 in previous work [19,[44][45][46][47][48][49] and for other oxides such as ZnO [50], TiO 2 [51] and MgO [30] where it was also found that the RT-FM is strongly affected by V O . With Sm 3+ and Sr 2+ doping, it is possible to increase the number of Ce 3+ /V O coupling pairs, giving rise to increased M S values.…”

Section: Resultssupporting

confidence: 88%

Modification of Ce valence states by Sm/Sr co-doping of CeO 2 nanoparticles for improved magneto-electrochemical properties

et al. 2016

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Section: Resultssupporting

confidence: 88%

Modification of Ce valence states by Sm/Sr co-doping of CeO 2 nanoparticles for improved magneto-electrochemical properties

et al. 2016

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“…Wang et al . proposed that the peak at binding energy 529.01 eV can be attributed to lattice oxygen ions in CeO 2 , the peak at 530.13 eV to absorbed oxygen, and the peak at 531.33 eV to lattice oxygen ions in Ce 2 O 3 33 . Thus, the peak in the O1s spectra at 531.5 eV, which was attributed to surface oxygen, should include a certain content of Ce 3+ -related surface defects, i.e.…”

Section: Resultsmentioning

confidence: 99%

Oxygen vacancy clusters essential for the catalytic activity of CeO2 nanocubes for o-xylene oxidation

Wang

et al. 2017

Sci Rep

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Catalytic oxidation of o-xylene was investigated on CeO2 nanocubes calcined at 350, 450, 550, and 650 °C, among which the samples calcined at 550 °C exhibited the highest activity and long durability. Positron annihilation spectroscopy measurements revealed that the size and distribution of oxygen vacancies for CeO2 nanocubes could be tuned by carefully controlling the calcination temperature. An excellent linear correlation between a factor related to size and density of oxygen vacancy clusters and reaction rate of o-xylene oxidation was revealed on ceria nanocubes. This means that oxygen vacancy clusters with suitable size and distribution are responsible for catalytic reaction via simultaneous adsorption and activation of oxygen and o-xylene. Electron spin resonance spectra revealed that over the CeO2 cubes, water vapor significantly promoted the formation of ∙OH radicals with a sharp decrease in the signals relating to oxygen vacancies, accelerating the transformation of o-xylene to the intermediate benzoate species, resulting in an enhancement of catalytic activity. Water thus serves as a “smart” molecule; its introduction into the feed mixture further confirmed the key role of oxygen vacancies in the catalytic performance of CeO2 nanocubes. A possible mechanism of oxygen vacancy formation during the calcination process was also proposed.

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“…The binding energy peaks labeled as V1 and V2 are located at 883.26 eV and 902.81 eV, indicating the Ce 3+ 3d 5/2 and Ce 3+ 3d 3/2 . The peaks (U1, U2 U3, U4, U5, and U6) of Ce 4+ 3d 5/2 and Ce 4+ 3d 3/2 are respectively shown at binding energy of 881.48, 888.34, 897.73, 899.85, 907.05, and 916.34 eV [32–34]. Compared with the sample after UV irradiation in Fig.…”

Section: Resultsmentioning

confidence: 99%

Room-Temperature Magnetism of Ceria Nanocubes by Inductively Transferring Electrons to Ce Atoms from Nearby Oxygen Vacancy

Kang

Guo

et al. 2015

Nano-Micro Lett.

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Ceria (CeO2) nanocubes were synthesized by a hydrothermal method and weak ferromagnetism was observed in room temperature. After ultraviolet irradiation, the saturation magnetization was significantly enhanced from ~3.18 × 10−3 to ~1.89 × 10−2 emu g−1. This is due to the increase of oxygen vacancies in CeO2 structure which was confirmed by X-ray photoelectron spectra. The first-principle calculation with Vienna ab-initio simulation package was used to illustrate the enhanced ferromagnetism mechanism after calculating the density of states (DOSs) and partial density of states (PDOSs) of CeO2 without and with different oxygen vacancies. It was found that the increase of oxygen vacancies will enlarge the PDOSs of Ce 4f orbital and DOSs. Two electrons in one oxygen vacancy are respectively excited to 4f orbital of two Ce atoms neighboring the vacancy, making these electron spin directions on 4f orbitals of these two Ce atoms parallel. This superexchange interaction leads to the formation of ferromagnetism in CeO2 at room temperature. Our work indicates that ultraviolet irradiation is an effective method to enhance the magnetism of CeO2 nanocube, and the first-principle calculation can understand well the enhanced magnetism.

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Oxygen vacancy and Ce3+ ion dependent magnetism of monocrystal CeO2 nanopoles synthesized by a facile hydrothermal method

Cited by 158 publications

References 46 publications

Modification of Ce valence states by Sm/Sr co-doping of CeO 2 nanoparticles for improved magneto-electrochemical properties

Modification of Ce valence states by Sm/Sr co-doping of CeO 2 nanoparticles for improved magneto-electrochemical properties

Oxygen vacancy clusters essential for the catalytic activity of CeO2 nanocubes for o-xylene oxidation

Room-Temperature Magnetism of Ceria Nanocubes by Inductively Transferring Electrons to Ce Atoms from Nearby Oxygen Vacancy

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