Structural, FT-IR, XRD and Raman scattering of new rare-earth-titanate pyrochlore-type oxides LnEuTi2O7 (Ln=Gd, Dy)

Garbout, A.; Taazayet‐Belgacem, I. Ben; Férid, Mokhtar

doi:10.1016/j.jallcom.2013.03.279

Cited by 55 publications

(18 citation statements)

References 42 publications

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“…[17][18][19] Here in this work we demonstrate that the microwave (MW) -assisted method produces off-equilibrium (metastable) pyrochlore-type phases with varying amounts of anti-site defects, in agreement with other more recently developed alternative synthesis methods, e.g. [20][21][22] In the last decades several alternative routes have been proposed such as microwave (MW) synthesis, molten salt mediated synthesis, co-precipitation of hydroxides, sol-gel and citrate based methods, and mechanical milling, where the time and temperature requirements for synthesis are significantly reduced. 19 Traditionally, RE 2 Ti 2 O 7 compounds are prepared by solid state reactions, which require repeated and long synthesis procedures at temperatures of up to ≈ 1400 ºC and intensive grinding at the initial and intermediate stages of processing to achieve single phase material.…”

Section: Introductionsupporting

confidence: 83%

Anti-site disorder and physical properties in microwave synthesized RE₂Ti₂O₇ (RE = Gd, Ho) pyrochlores

et al. 2015

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In this work we report on the microwave assisted synthesis of nano-sized Gd 2 Ti 2 O 7 (GTO) and Ho 2 Ti 2 O 7 (HTO) powders from the RE 2 Ti 2 O 7 pyrochlore family (RE = rare earth). Synchrotron X-ray powder diffraction was used to study RE-Ti cationic anti-site defects with concentrations that decrease in both samples with increasing temperature starting from 1100 ºC, and the defects disappear at 1400 ºC. SQUID magnetometry measurements revealed that GTO shows a predominantly anti-ferromagnetic structure, whereas HTO exhibits magnetic saturation and a ferromagnetic component at low temperature. Impedance spectroscopy data revealed strongly increased ionic oxygen vacancy conduction in HTO ceramic pellets as compared to GTO, which may be associated with a higher degree of oxygen vacancy disorder. This argument was supported by Raman spectroscopy data.

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Section: Introductionsupporting

confidence: 83%

Anti-site disorder and physical properties in microwave synthesized RE₂Ti₂O₇ (RE = Gd, Ho) pyrochlores

et al. 2015

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“…49,50 Therefore, the FTIR spectra of La 2 Sn 2 O 7 prepared with different methods were recorded between 400 to 1000 cm −1 . The region of interest in the FTIR absorption spectra of inorganic compounds is usually in the range of 100-1000 cm −1 , which is generally attributed to the vibrations of cations in the crystal lattice.…”

Section: Ftir Study On the La 2 Sn 2 O 7 Supports Prepared By Differementioning

confidence: 99%

High surface area La₂Sn₂O₇ pyrochlore as a novel, active and stable support for Pd for CO oxidation

Tian

Peng

et al. 2015

Catal. Sci. Technol.

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A high surface area mesoporous La 2 Sn 2 O 7 compound with a well crystallized pyrochlore structure has been successfully prepared by a simple low temperature hydrothermal ĲLa 2 Sn 2 O 7 -HT) method. As a support for Pd, a catalyst with a significantly higher activity for CO oxidation has been achieved in comparison with the other two non-mesoporous pyrochlores prepared by co-precipitation ĲLa 2 Sn 2 O 7 -CP) and sol-gel ĲLa 2 Sn 2 O 7 -SG) methods. The CO adsorption-desorption and STEM results demonstrate that on Pd/La 2 Sn 2 O 7 -HT, the highest Pd dispersion can be achieved among all of the catalysts. Moreover, compared with Pd/La 2 Sn 2 O 7 -CP and Pd/La 2 Sn 2 O 7 -SG, more active oxygen species were formed on Pd/La 2 Sn 2 O 7 -HT. It is believed that these are the two major reasons accounting for the superior CO oxidation activity of Pd/La 2 Sn 2 O 7 -HT. Furthermore, this catalyst also shows a stable reaction performance in the presence of water vapour. In conclusion, the mesoporous La 2 Sn 2 O 7 -HT pyrochlore is an excellent support for Pd, and has the potential to be applied in some real exhaust control processes.Catal. Sci. Technol. This journal is Fig. 10 Water resistance (a) and durability test (b) of the 1% Pd/La 2 Sn 2 O 7 -HT catalyst for CO oxidation.

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“…The medium absorption band at 561 cm -1 and the broad absorption band shown as a shoulder at 694 cm -1 are related with the Ti-O stretching vibration in TiO 6 octahedron and are assigned to F 1u band. The band at 561 cm -1 with the shoulder 694 cm -1 occurs as the characteristic absorption bands in the titanium pyrochlore spectra [19,20]. The above absorption bands give the evidence that the prepared sample is of pyrochlore structure.…”

Section: Resultsmentioning

confidence: 85%

Ionic conduction properties of nanocrystalline Er2Ti2O7 functional material

Sandeep¹

2020

Semicond. phys. quantum electron. and optoelectron.

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The rare-earth titanate Er 2 Ti 2 O 7 nanoceramic prepared by the modified combustion technique exhibits cubic pyrochlore structure with the space group m Fd3. Powder XRD and vibrational spectroscopic tools have been used for structural identification and confirmation. The detailed optical and photoluminescence (PL) properties of the sample have been analyzed using UV-Vis diffuse reflectance spectroscopy and PL spectroscopy. Impedance spectroscopic studies have revealed that the material exhibits conduction by hopping of ions, which increases with temperature. Z-View software has been used to fit the impedance data and deduce the electrical parameters of the samples from the equivalent circuit. The grain activation energy is less than that of grain boundary, which implies that grain conduction is predominant in the sample. The optical and electrical studies confirm that the material is a possible candidate to fabricate optical devices and construct solid oxide fuel cells.

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Structural, FT-IR, XRD and Raman scattering of new rare-earth-titanate pyrochlore-type oxides LnEuTi2O7 (Ln=Gd, Dy)

Cited by 55 publications

References 42 publications

Anti-site disorder and physical properties in microwave synthesized RE₂Ti₂O₇ (RE = Gd, Ho) pyrochlores

Anti-site disorder and physical properties in microwave synthesized RE₂Ti₂O₇ (RE = Gd, Ho) pyrochlores

High surface area La₂Sn₂O₇ pyrochlore as a novel, active and stable support for Pd for CO oxidation

Ionic conduction properties of nanocrystalline Er2Ti2O7 functional material

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Structural, FT-IR, XRD and Raman scattering of new rare-earth-titanate pyrochlore-type oxides LnEuTi2O7 (Ln=Gd, Dy)

Cited by 55 publications

References 42 publications

Anti-site disorder and physical properties in microwave synthesized RE2Ti2O7 (RE = Gd, Ho) pyrochlores

Anti-site disorder and physical properties in microwave synthesized RE2Ti2O7 (RE = Gd, Ho) pyrochlores

High surface area La2Sn2O7 pyrochlore as a novel, active and stable support for Pd for CO oxidation

Ionic conduction properties of nanocrystalline Er2Ti2O7 functional material

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Product

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Anti-site disorder and physical properties in microwave synthesized RE₂Ti₂O₇ (RE = Gd, Ho) pyrochlores

Anti-site disorder and physical properties in microwave synthesized RE₂Ti₂O₇ (RE = Gd, Ho) pyrochlores

High surface area La₂Sn₂O₇ pyrochlore as a novel, active and stable support for Pd for CO oxidation