Structural/surface characterization and catalytic evaluation of rare-earth (Y, Sm and La) doped ceria composite oxides for CH3SH catalytic decomposition

He, Dedong; Chen, Dingkai; Hao, Husheng; Yu, Jianguo; Liu, Jiangping; Lu, Jichang; Liu, Feng; Wan, Gengping; He, Shan; Luo, Yongming

doi:10.1016/j.apsusc.2016.08.129

Cited by 78 publications

(49 citation statements)

References 51 publications

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“…Finally we will calculate the magnetization M of a Sm doped CeO 2 NP. The radius of the doping ion Sm 3+ (1.17 Å) is larger compared to that of Ce 4+ (0.97 Å) and leads to increasing of the lattice what is in qualitative agreement with the experimental data of many authors . The grain size decreases with increasing Sm concentration .…”

Section: Numerical Results and Discussionsupporting

confidence: 89%

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Magnetic Properties of Rare Earth Doped SnO₂, TiO₂ and CeO₂ Nanoparticles

Apostolov

Apostolova

Wesselinowa

2018

Physica Status Solidi (b)

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The magnetic properties of rare earth doped SnO 2 , TiO 2 , and CeO 2 nanoparticles are studied theoretically. The discrepancies in the literature for some doping cases are explained, for example, the lattice parameters and the magnetization in Pr and Sm doped CeO 2 nanoparticles. There is a strong connection between the lattice deformations and the magnetization M. M decreases (except for Y doped CeO 2 ) due to the larger radius of the rare earth ions compared to that of the host ions which leads to increase of the lattice parameters and decrease of the exchange interactions. The decrease of M is due also to the enhanced number of oxygen vacancies with increasing dopant concentration. For Y doping the lattice parameters decrease and M increases with increasing Y concentration. We have discussed the origin of the different behavior of M in rare earth doped nanoparticles.

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Section: Numerical Results and Discussionsupporting

confidence: 89%

“…This decreasing is in qualitative agreement with the experimental data. Many authors reported a decrease of the lattice parameters in Y 3+ doped CeO 2 NPs . We obtain an increasing of the exchange interaction constant

J_{d}

in the defect states.…”

Section: Numerical Results and Discussionsupporting

confidence: 58%

Magnetic Properties of Rare Earth Doped SnO₂, TiO₂ and CeO₂ Nanoparticles

Apostolov

Apostolova

Wesselinowa

2018

Physica Status Solidi (b)

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“…In fact oxide of rare earth elements have been widely used as structural or electronic promoters to improve the activity, selectivity and thermal stability of CeO 2 through the formation of solid solution [26][27]29]. When doping with lanthanide cations an increase in the concentration of oxygen vacancies in the ceria structure is expected.…”

Section: Introductionmentioning

confidence: 99%

“…Thus rare earth elements (Gd, La, Y, Eu, Pr, Sm, Nd) are a good choice for this [26][27]. In fact oxide of rare earth elements have been widely used as structural or electronic promoters to improve the activity, selectivity and thermal stability of CeO 2 through the formation of solid solution [26][27]29].…”

Section: Introductionmentioning

confidence: 99%

“…For some practical applications dopants such as transition and non-transition metal ions may be introduced in the lattice of support like CeO 2 , increasing its temperature stability and ability to store and release oxygen [25][26][27]. Metallic cations with ionic radius and electronegativity close to those of cerium are thought to be the most appropriate modifiers of structural and chemical properties of ceria [28].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and characterization of Rh/MnO 2 -CeO 2 /Al 2 O 3 catalysts for CO-PrOx reaction

Laguna

López-Cartés

2017

Molecular Catalysis

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Rh/MnO 2 -CeO 2 /Al 2 O 3 catalysts with different manganese-to-ceria ratios have been synthesized, characterized and tested in CO-PrOx reaction. The physicochemical properties of the solids were studied by XRD, Raman spectroscopy, BET surface area, H 2 -TPR, TGA-DTG and TEM. The differences observed in the textural, structural and redox properties were related to the Mn-toceria ratio of the samples. The segregation of Mn species was observed at high Mn-to-Ce ratios.In opposite way, MnO 2 -CeO 2 solid solutions were obtained at low Mn to Ce ones. In this last case, the physicochemical properties of the solids were favored by the intimate Rh-Ce-Mn contact. The effect of the Mn-Ce presence on Rh catalysts which promotes the catalytic behavior towards selective CO oxidation was observed to be better at low temperatures. At higher temperatures, Mn species promote the Reverse Water Gas Shift reaction, whilst ceria promotes the H 2 oxidation in the whole range of working temperatures.

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Asymmetric Oxygen Vacancies: the Intrinsic Redox Active Sites in Metal Oxide Catalysts

et al. 2019

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stability in many important reactions, [1] especially in some redox reactions, such as CO oxidation, [2] water-gas shift (WGS) reaction, [3] selective catalytic reduction of NO x , [4] oxidation of volatile organic compounds (VOCs), [5] and soot combustion. [6,7] It is commonly known that the catalytic reaction takes place at defect sites of these oxide catalysts. [8] However, it is not always found a monotonous relation between the catalytic performance and the concentration of a certain kind of defect sites, such as oxygen vacancies, [9,10] lattice distortion [11] and defect generated Lewis acid/base sites, [12,13] as well as metastable valence states of cations. [14] As discussed by McFarland and Metiu, [15] heterogeneous catalytic reactions are run under steady-state conditions instead of at equilibrium. It is difficult to accurately describe the catalytic performance of oxide catalysts using the property parameters of as-prepared catalysts, which are more likely to be in thermodynamic equilibrium during the preparation process. For example, according to many reports, the redox properties of catalysts were believed to relate to the amount of oxygen vacancies (regarded as active sites) in oxide catalysts. However, the steady-state concentration of oxygen vacancies is related to the rate of vacancy formation and that of vacancy vanishing. In other words, a real active oxygen vacancy should have high abilities of adsorbing the reactant molecules and desorbing the product molecules, allowing molecules easy come, easy go. To keep a balance of these two opposite abilities, the local environment of the oxygen vacancy plays an important role.It has been well accepted that doping of low-valence dopants in oxides can create oxygen vacancies due to a charge compensation effect, [16,17] accompanied by improved oxygen activation ability, which is usually considered as the key factor in promoting catalytic activity for redox reactions. However, when the oxides are doped by same-valence or high-valence dopants, the effect of doping on their catalytic performance will become much more complicated. Fortunately, for most oxidation reactions catalyzed by metal oxides, the lattice oxygen atoms at/near the surface of oxides are the active species based on a generally accepted Mars− van Krevelen (MvK) mechanism. [18] Therefore, the bonding situations of these surface oxygen atoms should be the key factors affecting the catalytic performance.In the last few years, researchers have paid more attention to the chemical environment of oxygen vacancies, including To identify the intrinsic active sites in oxides or oxide supported catalysts is a research frontier in the fields of heterogeneous catalysis and material science. In particular, the role of oxygen vacancies on the redox properties of oxide catalysts is still not fully understood. Herein, some relevant research dealing with M 1 -O-M 2 or M 1 -□-M 2 linkages as active sites in mixed oxides, in oxide supported single-atom catalysts, and at metal/oxide interfaces of oxide supporte...

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Structural/surface characterization and catalytic evaluation of rare-earth (Y, Sm and La) doped ceria composite oxides for CH3SH catalytic decomposition

Cited by 78 publications

References 51 publications

Magnetic Properties of Rare Earth Doped SnO₂, TiO₂ and CeO₂ Nanoparticles

Magnetic Properties of Rare Earth Doped SnO₂, TiO₂ and CeO₂ Nanoparticles

Synthesis and characterization of Rh/MnO 2 -CeO 2 /Al 2 O 3 catalysts for CO-PrOx reaction

Asymmetric Oxygen Vacancies: the Intrinsic Redox Active Sites in Metal Oxide Catalysts

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Structural/surface characterization and catalytic evaluation of rare-earth (Y, Sm and La) doped ceria composite oxides for CH3SH catalytic decomposition

Cited by 78 publications

References 51 publications

Magnetic Properties of Rare Earth Doped SnO2, TiO2 and CeO2 Nanoparticles

Magnetic Properties of Rare Earth Doped SnO2, TiO2 and CeO2 Nanoparticles

Synthesis and characterization of Rh/MnO 2 -CeO 2 /Al 2 O 3 catalysts for CO-PrOx reaction

Asymmetric Oxygen Vacancies: the Intrinsic Redox Active Sites in Metal Oxide Catalysts

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Magnetic Properties of Rare Earth Doped SnO₂, TiO₂ and CeO₂ Nanoparticles

Magnetic Properties of Rare Earth Doped SnO₂, TiO₂ and CeO₂ Nanoparticles