Ceramics

Sōmiya, Shigeyuki

doi:10.1016/b0-12-227410-5/00092-2

Cited by 5 publications

(2 citation statements)

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“…The open cavities formed by this framework are occupied by Cs atoms (at 8 c sites). This distribution has the advantage of enhancing the dielectric properties at the microwave regime for communication applications, such as filters, resonators, and antennas. , …”

Section: Resultsmentioning

confidence: 99%

Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs₂AgSbCl₆ Double Perovskite

Rodrigues

Escanhoela

Fragoso

et al. 2021

Ind. Eng. Chem. Res.

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Despite the rapid development and enormous success of organic–inorganic hybrid halide perovskites (AB′X 3), such as CH3NH3PbI3 as absorbers for perovskite-based solar cells (PSCs), the commercial applications of photovoltaic techniques still face several challenges, such as decomposition when exposed to light and moisture, and lead toxicity. On the other hand, the double perovskites (A 2 B′B″X 6) are derived from the AB′X 3 when half of the octahedrally coordinated B′-cations are partially replaced by the suitable B″-cations. They are attracting attention due to a new design strategy to replace Pb2+ ions with the couple of a monovalent M + ion and a trivalent M 3+ ion, leading to a new family of quaternary double perovskites. In this way, we aim to synthesize and characterize Cs2AgSbCl6 powdered samples, designed for solar cell applications. The crystalline phase and morphological features are investigated by X-ray powder diffraction (XRPD), neutron powder diffraction (NPD), scanning electron microscopy (SEM) in complement with UV–vis spectroscopy, showing a suitable band gap of 2.7 eV. The solution synthesis method proved to be efficient in obtaining polycrystalline-Cs2AgSbCl6 samples in a cubic ordered phase. DFT calculations also provided insights on the vibrational properties of Cs2AgSbCl6, corroborating the experimental data and elucidating the optical activity of Raman and infrared modes.

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Section: Resultsmentioning

confidence: 99%

Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs₂AgSbCl₆ Double Perovskite

Rodrigues

Escanhoela

Fragoso

et al. 2021

Ind. Eng. Chem. Res.

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“…It was well known that tetragonal and/or cubic structure was stabilized with the introduction of the oxygen vacancy by doping with several rare earth oxides (MgO, Y 2 O 3 , etc.) (27,28,33). The introduction of vacancies by substituting some of the oxygen atoms with nitrogen atoms also stabilized the tetragonal and/or cubic structure (27,28).…”

Section: Surface Characterizationmentioning

confidence: 96%

Zirconium Oxide-based Cathode without Platinum Group Metals for PEFC

et al. 2009

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Partially oxidized zirconium carbonitrides (Zr-CNO) powders were evaluated as a non-precious cathode for polymer electrolyte fuel cells (PEFCs). Zr-CNO powders were prepared from zirconium carbonitrides (Zr-CN) with heat-treatment under 0.25%O 2 /2%H 2 /N 2 at 1000 -1400 o C. The slow scan voltammetry was performed to evaluate the catalytic activity for the oxygen reduction reaction (ORR) under nitrogen and oxygen in 0.1 mol dm -3 H 2 SO 4 at 30 o C. Although the onset potential of ORR for untreated Zr-CN is 0.55 V vs. reversible hydrogen electrode (RHE), the onset potential of the appropriate oxidized Zr-CNO reached 0.97 V vs. RHE. XRD and XPS data suggested that the surface of the Zr-CNO was oxidized to ZrO 2 and Zr-CN remained in the inner part of the each particle. The existence of tetragonal and/or cubic ZrO 2 in the XRD patterns of the Zr-CNO suggested that the vacancies on the surface of the Zr-CNO might affect the catalytic activity for the ORR. IntroductionPolymer electrolyte fuel cells (PEFCs) are expected to become a prominent technology in a variety of energy generation applications such as residential, portable and automotive power sources due to their high efficiency of energy conversion, low pollutant emission, and high power density. There are, however, some technological and economical problems before the commercialization of PEFCs. One of the technological problems is a large overpotential of oxygen reduction reaction (ORR), although platinum is utilized as an electrocatalyst in the present. The large overpotential of the ORR should be reduced to obtain high energy efficiency. On the other hand, one of the economical problems is the high cost of platinum catalysts due to the limitation of its amount of resources. Although many attempts have been made to reduce platinum usage, the cost of electrodes still remains high. Therefore, development of a non-precious metal based catalyst Pt is strongly required because Pt is scarce and expensive.Many studies have been performed to develop non-platinum cathode catalysts for lowtemperature fuel cells. Macrocyclic transition metal (cobalt or iron was mainly used as active site) complexes and novel metal chalcogenides were famous as candidates for the alternative platinum catalyst. Since the early 1960s, metal transition complexes of the N 4 -chelate type such as phtalocyanines, porphyrins, and tetraazaanulens, etc had some catalytic activity for the ORR (1-3). However, these compounds were unstable in acidic and oxidizing atmpsphere (4). In recent years, heat-treatment of the carbon-supported N 4 -chelates containing iron and/or cobalt was found to enhance the catalytic activity and ECS Transactions, 25 (1) 129-139 (2009) 10.1149/1.3210565 © The Electrochemical Society 129 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.236.-224.35 Downloaded on 2015-06-25 to IPstability greatly (5). However, the stability of the complexes is still insufficient, because the condition of PEFC ...

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DC conductivity mechanism in La0.7Sr0.3MnO3 (LSMO)-ZnO nanocomposites

Chatterjee

Labar²,

Nooruddin

et al. 2023

Journal of Applied Physics

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La0.7Sr0.3MnO3 (LSMO)-ZnO nanocomposites with varying concentrations of ZnO have been synthesized using the solution combustion method. A bimodal particle size distribution has been formed in all the samples. The crystallite size increases in the composites as compared to LSMO. The study on electrical resistivity reveals that LSMO exhibits a metal-to-insulator transition at 359 K, while the inclusion of ZnO suppresses the metallic behavior in the composites and increases the resistivity. Transport behavior of the samples in metallic and semiconducting regions has been explained with a known polynomial equation and a two-channel conduction model obeying the small polaron hopping mechanism, respectively. A very low activation energy in the range of 10–12 meV is observed due to smaller-sized particles. The presence of ZnO drives the hopping mechanism from adiabatic in LSMO to become non-adiabatic in the composites and enhances the maximum temperature coefficient of resistance. 80% LSMO-20% ZnO (by weight ratio) composite shows a maximum TCR of −29.81%/K at 248 K, which makes it a potential candidate for several applications in sensing devices. The Curie temperature of the material decreases with the increase in ZnO content in the sample. The results of this study also confirm the existence of correlation between the electrical and magnetic properties of LSMO.

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Ceramics

Cited by 5 publications

References 50 publications

Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs₂AgSbCl₆ Double Perovskite

Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs₂AgSbCl₆ Double Perovskite

Zirconium Oxide-based Cathode without Platinum Group Metals for PEFC

DC conductivity mechanism in La0.7Sr0.3MnO3 (LSMO)-ZnO nanocomposites

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Ceramics

Cited by 5 publications

References 50 publications

Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs2AgSbCl6 Double Perovskite

Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs2AgSbCl6 Double Perovskite

Zirconium Oxide-based Cathode without Platinum Group Metals for PEFC

DC conductivity mechanism in La0.7Sr0.3MnO3 (LSMO)-ZnO nanocomposites

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Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs₂AgSbCl₆ Double Perovskite

Experimental and Theoretical Investigations on the Structural, Electronic, and Vibrational Properties of Cs₂AgSbCl₆ Double Perovskite