Synthesis of nanocrystalline conducting composite oxides based on a non-ion selective combined complexing process for functional applications

Zhou, Wei; Jin, Wanqin

doi:10.1016/j.jallcom.2006.02.029

Cited by 120 publications

(61 citation statements)

References 29 publications

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“…PdO and Pd 0.95 Mn 0.05 O powders were synthesised to study the effect of Mn alloying on microstructure stability of the nanoparticles using the combined EDTA-citrate complexing sol-gel processing [16] [VerborgenE]by following similar procedures as described in ref. [13].…”

Section: Methodsmentioning

confidence: 99%

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

et al. 2009

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The effect of Mn alloying on PdO powder and Pd‐impregnated Pd + YSZ cathode for the O2 reduction reaction in intermediate temperature solid oxide fuel cells has been studied in detail. The microstructure, thermal stability, electrochemical activity and performance stability of the powder and cathode were analysed using thermal gravimetric analysis, X‐ray diffraction, scanning electron microscopy/energy dispersive spectroscopy and electrochemical impedance spectroscopy. The results indicate that an addition of 5 mol.‐% Mn effectively inhibits the growth and coalescence of Pd and PdO particles at high temperatures and stabilises the microstructure of the powders and the electrode; as a consequence, the electrochemical performance and stability of the cathode are significantly improved. The electrochemical performance of the Pd + YSZ and Pd0.95Mn0.05 + YSZ cathodes so prepared is much better than that of the conventional LSM‐based cathodes and is also comparable with the mixed ionic and electronic conducting oxide cathodes such as LSCF.

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Section: Methodsmentioning

confidence: 99%

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

et al. 2009

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“…Citric acid is a chelating agent which forms complexes with metal ions in the sol. It helps the molecularlevel mixing of metal ions [30]. Therefore, with higher amount of citric acid, the compositional homogeneity of the gel would be more.…”

Section: Resultsmentioning

confidence: 99%

Effect of fuel-to-oxidant ratio on phase constituents, microstructure and magnetic properties of NiFe2O4-based composite nanopowder synthesized by sol–gel auto-combustion method

Alamolhoda

Mirkazemi

Benvidi

et al. 2015

J Sol-Gel Sci Technol

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In this research, NiFe 2 O 4 -based composite nanopowder with 0.8, 1, 1.35, 1.7 fuel-to-oxidant (F/O) ratios was synthesized by sol-gel auto-combustion method. Changes in phase constituents, microstructure and magnetic properties due to changes in F/O ratios were evaluated by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM) techniques. XRD and Raman spectroscopy results show the presence of NiFe 2 O 4 , FeNi 3 , a-Fe 2 O 3 and NiO phases. The amount of nickel ferrite was increased, while the amount of FeNi 3 was decreased with increasing F/O ratio from 0.8 to 1.35. Mean crystallite sizes of the samples are in the range of 40-46 nm. FESEM studies depicted the formation of NiFe 2 O 4 particles coexisting with FeNi 3 phase. Changes in F/O ratios alter the saturation magnetization values from 37 to 60 emu/g as a result of changes in FeNi 3 and NiFe 2 O 4 amounts. Coercivity values are in the range of 135-177Oe. Graphical Abstract In this research nano-sized NiFe 2 O 4 powders with 0.8, 1, 1.35, 1.7 Fuel to Oxidant (F/O) ratios were synthesized by sol-gel auto-combustion method. FESEM studies depicted the formation of NiFe 2 O 4 particles coexisting with FeNi 3 phase. Changes in F/O ratios alter the saturation magnetization values from 37 to 60emu/g as a result of changes in FeNi 3 and NiFe 2 O 4 amounts. Coercivity values are in the range of 135 to 177Oe.

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“…pH 9, and EDTA has the fourth pK a at 10.3. 24 To our knowledge, the behavior of Co− EDTA complexes in alkaline solutions has not been studied in detail. On the other hand, the dependence of Φ on the total concentration was explored at pH 8 in the absence and in the presence of urea (Figure 2b).…”

Section: Articlementioning

confidence: 99%

Chaotropic Agents Boosting the Performance of Photoionic Cells

et al. 2015

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Photoionic cells are a simple and scalable concept for direct solar energy storage, where the redox fuels produced by the photoreaction are separated in different phases to prevent recombination. The presence of chaotropic agents such as urea, that break the structure of water, was found to drastically enhance the quantum yield; a 10-fold increase of quantum yield to over 13% was achieved by addition of chaotropes into a system based on the reductive quenching of Azure B by Co(II)EDTA in water and the extraction of the leuco dye in 1,2-dichloroethane. ■ INTRODUCTIONSolar energy conversion is one of the global challenges for a sustainable economy. At present, two major routes are being followed: photovoltaic (PV) systems to generate electricity and solar thermal collectors to generate heat. However, all PV technologies must immediately distribute the produced electricity either to a storage system or to the electrical grid, irrespective of demand. Recently, we have proposed a simple and scalable concept for solar energy storage: photoionic cells. 1 This is an extension of the early work of Rabinowitch et al. 2−5 and Albery et al. 6−9 on photogalvanic cells (essentially photochemical concentration cells), but in photoionic cells the charge separation takes place at the interface between two immiscible electrolyte solutions. 1 The system is based on a dye−quencher couple where, upon light excitation, the excited dye (for example thionine) is quenched in the aqueous solution by the quencher (e.g., [Co(II)EDTA] 2− ) to form both an oxidized quencher (e.g., [Co(III)EDTA] − ) and reduced neutral dye (leucothionine) that partitions to the organic phase. The two immiscible liquid phases are separated, and the redox energy is stored in the respective electrolyte solutions. These two solutions can then be electrochemically discharged in a flow cell to generate electricity on demand. The main potential advantage of photoionic cells over classical solar cells is the unique ability to convert solar energy directly into "redox fuels" that can be consumed only when electricity is required to generate electricity to meet a specific demand.The original thionine−cobalt EDTA system 1 has some drawbacks, like low potential difference between the two photogenerated redox couples and very low solubility of thionine, which limits the quantum yield of the system. Another serious issue that has to be considered is dye aggregation, leading to significant loss of performance. In order to overcome such drawbacks, in this work we have explored Azure B (H 2 AzB) as an interesting alternative in the development of systems capable of capturing, converting, and storing solar energy in the form of reduced and oxidized photoproducts separated by a polarized interface formed between two immiscible electrolyte solutions.We have systematically studied the effects of the physicochemical and photophysical properties of a dye on the quantum yield, and we have optimized the reaction conditions in the photoionic cells in order to maximize the ...

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Synthesis of nanocrystalline conducting composite oxides based on a non-ion selective combined complexing process for functional applications

Cited by 120 publications

References 29 publications

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

Mn‐Stabilised Microstructure and Performance of Pd‐impregnated YSZ Cathode for Intermediate Temperature Solid Oxide Fuel Cells

Effect of fuel-to-oxidant ratio on phase constituents, microstructure and magnetic properties of NiFe2O4-based composite nanopowder synthesized by sol–gel auto-combustion method

Chaotropic Agents Boosting the Performance of Photoionic Cells

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