A Sol–Gel Route for the Synthesis of Bi2Ru2O7 Pyrochlore Oxide for Oxygen Reaction in Alkaline Medium

Kahoul, A.; Nkeng, Paul; Hammouche, A.; Naamoune, Farid; Poillerat, G.

doi:10.1006/jssc.2001.9346

Cited by 27 publications

(17 citation statements)

References 17 publications

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“…This is comparable with the similar study of synthesis of Bi 2 Ru 2 O 7 from polymer precursor. 15 Figure 2 is the XRD patterns for different calcination temperatures of Bi 2 Ru 2 O 7 calcined for 6 h in stagnant air. The crystalline structure was exhibited upon calcination at 600°C.…”

Section: Resultsmentioning

confidence: 99%

“…A sol-gel route, the Pechini process, has been reported for the synthesis of the fine powder Bi 2 Ru 2 O 7 . 15 The bismuth ruthenate pyrochlores, Bi 2 ͑Ru 2−x Bi x ͒O 7−␦ ͑x = 0.0, 0.2, 0.4, 0.6, 0.8͒, were synthesized by the reported method with some modification. Bismuth nitrate instead of bismuth oxide was used for easy dissolution in the solvent.…”

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confidence: 99%

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Bismuth Ruthenate-Based Pyrochlores for IT-SOFC Applications

Zhong

2006

Electrochem. Solid-State Lett.

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The densification and electrochemical activity for oxygen reduction of the bismuth ruthenate pyrochlores, Bi 2 ͑Ru 2−x Bi x ͒O 7−␦ ͑x = 0.0-0.8͒ synthesized by the Pechini method, have been investigated as the interconnect and cathode materials for intermediate temperature solid oxide fuel cells ͑IT-SOFCs͒. The substitution of bismuth on the ruthenium site significantly improves the densification process. Some compositions of the pyrochlore family are promising coating materials for metallic interconnects. Anode-supported fuel cells with doped ceria as the electrolyte have been fabricated and tested. Impedance spectra of the fuel cells demonstrate high catalytic activity for oxygen reduction. The area-specific resistance at 600°C is less than 1.0 ⍀ cm 2 .Solid oxide fuel cells ͑SOFCs͒ are promising power generation devices for the future as they have demonstrated high energy conversion efficiency, high power density, extremely low pollution, in addition to flexibility in using hydrocarbon fuel. A major obstacle for commercial applications of SOFC still is high cost, both in terms of materials and processing. An intermediate temperature solid oxide fuel cell ͑IT-SOFC͒ operating between 500-800°C, which allows the utilization of inexpensive metallic interconnects and sealing materials, can significantly reduce the cost of SOFCs. The IT-SOFC also will have better reliability and portability. To keep up with the performance of traditional SOFC that operates between 900-1000°C, new materials with improved performance have to be used. An essential new material for IT-SOFC is metallic interconnects which have excellent mechanical strength, premium performance due to low resistance, and low cost due to easy fabrication. Some chromium-based alloys have become the leading candidates of the metallic interconnect due to their thermal expansion match to the other fuel cell components and relative stability in air at the operating temperature. 1,2The chromium alloys do oxidize in air at high temperatures. A chromia ͑Cr 2 O 3 ͒ scale that forms on the surface is electrically conductive. The scale adheres on the alloy and slows down further oxidation. When the temperature is below 800°C, the chromium alloy-based metallic interconnect is reasonably stable. The conductive-scale-forming alloys are quite unique among high temperature alloys. However, some chromium species ͓probably CrO 3 and/or CrO 2 ͑OH͒ 2 ͔ are volatile in air even below 700°C. Over time, the fuel cell fails due to chromium poisoning of the cathode. 3,4 It is necessary to develop a coating materials for metallic interconnects so that it does not contact the cathode directly. LaCrO 3 -, LaMnO 3 -, LaCoO 3 -based perovskites and ͑Mn,Co,Cr͒ 3 O 4 spinels have been investigated as the coating materials. 4-9 The coating material needs to be electrically conductive and dense enough to be gas tight. These coating materials do prevent ͑or slow down͒ chromium poisoning of the cathode and therefore enhance the life of the fuel cell stack. However, better coating materials a...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Bismuth Ruthenate-Based Pyrochlores for IT-SOFC Applications

Zhong

2006

Electrochem. Solid-State Lett.

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“…Traditionally, there are three basic reactions in Pechini process, i.e., chelating between metal cations and hydroxycarboxylic acid, esterification, and polymerization of excess hydroxycarboxylic acid with glycol [7,10,11]. Accordingly, mechanism for the generation of MoO 2 microsphere via modified Pechini method was proposed.…”

Section: Mechanismmentioning

confidence: 99%

“…Pechini route (polymerized complex method) is one of the most widely used sol-gel method to prepare various ceramics with controllable size and improved property compared to those elaborated through conventional procedure [10,11]. This method make use of certain weak b-hydroxycarboxylic acids (CA is preferred), which can form stable chelating complexes with many metal ions.…”

Section: Introductionmentioning

confidence: 99%

Ethanothermal reduction to MoO2 microspheres via modified Pechini method

Wang

Zhang

et al. 2006

Journal of Crystal Growth

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“…The method has been applied for certain metal oxides such as LiMn 2 O 4 spinel [10], Bi 2 Ru 2 O 7 pyrochlore, and La 1 − x Ca x CoO 3 perovskites [11][12][13]. A clear solution was obtained by heating a mixture of citric acid (50 g) and ethylene glycol (50 ml) (Aldrich) at 90°C for 30 min.…”

Section: Synthesis Of Fepo 4 Compoundmentioning

confidence: 99%

Electrochemical performances of FePO4-positive active mass prepared through a new sol–gel method

Kahoul

Hammouche

2009

Ionics

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This investigation is a contribution to the research on alternative cathode materials with much more promising performances for lithium batteries. It deals with the electrochemical properties of iron phosphate compound FePO 4 , chemically prepared through the so-called sol-gel Pechini process, terminated by a calcination of the product precursor at temperatures (T c ) ranging between 350°C and 650°C. A crystalline phase was obtained for temperatures ≥400°C. The particle size decreased with the decrease in T c , giving rise to a Brunauer-Emmett-Teller (BET)-specific surface area, S BET , as high as 28 m 2 g −1 for the sample annealed at 400°C. The electrochemical properties of FePO 4 -based composite cathodes were characterized on three-electrode laboratory cells. Charge-discharge cycling determined a maximum reversible capacity of 132 mAh g −1 , which fell with the increase in T c . A direct correlation was established between the activity of the material and its active surface area.

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A Sol–Gel Route for the Synthesis of Bi2Ru2O7 Pyrochlore Oxide for Oxygen Reaction in Alkaline Medium

Cited by 27 publications

References 17 publications

Bismuth Ruthenate-Based Pyrochlores for IT-SOFC Applications

Bismuth Ruthenate-Based Pyrochlores for IT-SOFC Applications

Ethanothermal reduction to MoO2 microspheres via modified Pechini method

Electrochemical performances of FePO4-positive active mass prepared through a new sol–gel method

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