Promising solid electrolyte material for an IT-SOFC: crystal structure of the cerium gadolinium holmium oxide Ce0.8Gd0.1Ho0.1O1.9 between 295 and 1023 K

Rahayu, Sri; Forrester, Jennifer S.; Kale, Girish M.; Ghadiri, Mojtaba

doi:10.1107/s2053229617017946

Cited by 7 publications

(5 citation statements)

References 22 publications

(30 reference statements)

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“…A Rietveld size/strain structural refinement was performed on the data obtained from XRD. P'Analytical X'Pert High Score plus software package was used for Rietveld refinement, detail of which can be found elsewhere [19][20][21][22]. Data comprised of Gaussian and Lorentzian components and a Pseudo-Voigt profile was used to refine the relative proportion of each component during the refinement process.…”

Section: Characterisationmentioning

confidence: 99%

Environmentally sustainable facile synthesis of nanocrystalline holmium hafnate (Ho2Hf2O7): Promising new oxide-ion conducting solid electrolyte

et al. 2020

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A 2 B 2 O 7 oxides with defect-fluorite structure are one of the potential candidates for solid oxide fuel cell electrolyte material due to their excessive thermodynamic stability in oxygen potential gradient at elevated temperature between 500 and 900 °C. Holmium hafnate nanoparticles have been synthesised through the Leeds Alginate Process (LAP) using inorganic salts of holmium and hafnium as starting materials immobilized in alginate beads. Ion exchange with sodium alginate and its subsequent thermal treatment have been used to prepare the nanopowder of Ho 2 Hf 2 O 7 . Thermal decomposition of dried beads is carried out at 700 °C for 2 h and 6 h to obtain the nanoparticles of Ho 2 Hf 2 O 7 . This calcination temperature was determined after carrying out simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/ DSC). High Temperature X-ray Diffraction (HT-XRD) was carried out to gain further insight into the thermal decomposition process in static ambient environment. HT-XRD analysis corroborated with the results obtained from TGA/DSC. Nanocrystalline powder of single phase Ho 2 Hf 2 O 7 has been obtained by calcination of oven dried ion-exchanged alginate beads in relatively low temperature range of 500-700 °C. Rietveld refinement of X-ray diffraction (XRD) data confirmed the formation of single phase defect fluorite structure of Ho 2 Hf 2 O 7 . The crystallographic parameters calculated from TEM and XRD analysis are in excellent agreement with each other. Furthermore, TEM-EDX analysis confirms that the Ho 2 Hf 2 O 7 synthesised by the facile alginate process is nearly stoichiometric. Raman spectroscopy gives evidence of the presence of oxide-ion vacancy in holmium hafnate which is supported with ac-impedance spectroscopy measurement at selected three temperatures. The present study suggests that the LAP has the capability of yielding on a large scale single phase defect-fluorite nanoparticles of electrolyte materials for solid oxide fuel cells in environmentally sustainable, economical and energy efficiently manner.

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Section: Characterisationmentioning

confidence: 99%

Environmentally sustainable facile synthesis of nanocrystalline holmium hafnate (Ho2Hf2O7): Promising new oxide-ion conducting solid electrolyte

et al. 2020

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“…NPs of Ce 0.8 Er 0.1 Gd 0.1 O 1.9 were prepared using the process called LAP developed by Kale and co-workers, , from commercial Ce(NO 3 ) 3 ·6H 2 O (>99% of purity), Er(NO 3 ) 3 · x H 2 O (>99.9% of purity), and Gd(NO 3 ) 3 ·6H 2 O (>99.9% of purity). The preparation procedure is shown in Figure .…”

Section: Methodsmentioning

confidence: 99%

“…We also incorporated gadolinium oxide (Gd 2 O 3 ) in the NPs, as they could increase the low phonon energy to ∼600 cm –1 and increase solubility of other rare-earth ions in ceria . For example, several techniques have been employed to synthesize ceria NPs, which include hydrothermal synthesis, combustion synthesis, and sol–gel. − For instance, an environmentally friendly carbon neutral sol–gel method called the leeds alginate process (LAP) has been developed by Kale et al , for synthesizing crystalline complex functional ceramic oxide NPs of controlled stoichiometry in a single step.…”

Section: Introductionmentioning

confidence: 99%

Erbium-Doped Nanoparticle–Polymer Composite Thin Films for Photonic Applications: Structural and Optical Properties

et al. 2020

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Erbium-doped nanocrystal (NC)-dispersed polymer thin films are attractive core materials for use in optical waveguides as they can provide high optical gain and enable the formation of compact waveguide amplifiers. Nonetheless, there are significant challenges associated with obtaining good dispersibility of NCs into a polymer matrix and favorable optical properties. Therefore, in this paper, we report the fabrication of Er3+-doped ceria (EGC) NCs employing the Leeds alginate process (LAP) and their incorporation into a siloxane polymer matrix. The surface morphology and compositional, structural, and optical properties of the fabricated films are evaluated to assess the NC dispersion and their suitability for the waveguide amplifier. The photoluminescence (PL) and lifetime measurements of the NCs–polymer nanocomposite thin film samples show intense, broadband PL emission of the Er3+ ions at 1534 nm (4I13/2 → 4I15/3 transition) with a full width at half-maximum (fwhm) of ∼64 nm and lifetime in the range of 2.6–3.0 ms. The inhomogeneously broadened PL spectra and improvement in lifetime of NCs in the polymer are important results that we report. The EGC NCs–polymer nanocomposite thin films also exhibit excellent transparency in the NIR wavelength range and a refractive index in the range of 1.53–1.58 in the visible wavelength. The work presented here clearly demonstrates the potential of using high-quality Er-doped nanocomposite polymer thin films for interesting applications such as compact low-cost waveguide amplifiers and lasers.

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“…Data was comprised of Gaussian and Lorentzian components and a Pseudo-Voigt profile was used to refine the relative proportion of each component during refinement process. Detail of Rietveld procedure can be found elsewhere [15][16][17][18] .…”

Section: 2characterisationmentioning

confidence: 99%

Structural study of holmium zirconate nanoparticles obtained through carbon neutral sol-gel process

et al. 2019

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The pyrochlore oxides are of potential interest as ion conducting electrolyte for intermediate temperature solid oxide fuel cell (SOFC). Nanopowders of holmium zirconate have been synthesised through ion-exchange between sodium alginate gel and metal complex solution followed by its thermal decomposition. Nanoparticles of Ho2Zr2O7 were obtained by calcining the dried gel beads at 700˚C for 2h and 6h duration respectively. An insight into calcination has been obtained employing simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC). Thermal decomposition was also followed using High Temperature X-ray Diffraction (HTXRD) in static ambient atmosphere. Results from TGA/DSC and HTXRD corroborate each other. Fine crystalline nanopowders of single phase Ho2Zr2O7 could be obtained after thermal decomposition at relatively low temperature (600-700˚C). Powder X-ray diffraction (XRD) revealed that the material has crystallized as single phase cubic Ho2Zr2O7 with defect fluorite structure. XRD and Raman spectroscopy were used to analyse the local structure of holmium zirconate. XRD scans of holmium zirconate and holmium hafnate prepared through identical method have been compared and effect of cationic radius of Zr 4+ and Hf 4+ on B-site was studied. The crystallographic data obtained from XRD and transmission electron microscopy (TEM) are in good agreement with each other. This sol gel method referred also as Leeds Alginate Process (LAP) is simple, cost effective, energy efficient and carbon neutral for the preparation of pyrochlore oxides (A2B2O7) solid electrolyte material for SOFC.

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Promising solid electrolyte material for an IT-SOFC: crystal structure of the cerium gadolinium holmium oxide Ce_0.8Gd_0.1Ho_0.1O_1.9 between 295 and 1023 K

Cited by 7 publications

References 22 publications

Environmentally sustainable facile synthesis of nanocrystalline holmium hafnate (Ho2Hf2O7): Promising new oxide-ion conducting solid electrolyte

Environmentally sustainable facile synthesis of nanocrystalline holmium hafnate (Ho2Hf2O7): Promising new oxide-ion conducting solid electrolyte

Erbium-Doped Nanoparticle–Polymer Composite Thin Films for Photonic Applications: Structural and Optical Properties

Structural study of holmium zirconate nanoparticles obtained through carbon neutral sol-gel process

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