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Redox stability and electrochemical study of nickel doped chromites as anodes for H2/CH4-fueled solid oxide fuel cells

Paper ID Volume ID Publish Year Pages File Format Full-Text
46438 46439 2012 11 PDF Available
Title
Redox stability and electrochemical study of nickel doped chromites as anodes for H2/CH4-fueled solid oxide fuel cells
Abstract

The influence of nickel and strontium incorporation in LaCrO3 on the crystalline structure, redox behavior and electrochemical performance by impedance spectroscopy using symmetrical cells has been studied. Namely, the La1−xSrxCr1−yNiyO3−δ (x = 0, 0.15; y = 0.05, 0.1, 0.2) system was investigated. Structural and redox evolution has been monitored by X-ray diffraction in oxidized and reduced samples. Reduced samples kept the initial perovskite structure although metallic nickel nanoparticles were detected on the perovskite grain surface by TEM analysis. The re-oxidized surface did not present nickel particles, suggesting the nickel re-incorporation into perovskite lattice coupled with cation diffusion. The perovskites were tested as SOFC anodes and the polarization resistance depended on the nickel stoichiometry and the reduction temperature. La0.85Sr0.15Cr0.9Ni0.1O3−δ reduced at 800 °C showed the lowest polarization resistance, both in hydrogen and methane. In fact this composition showed a 20% methane conversion at 900 °C for the methane steam reforming in a fixed bed reactor. Tolerance to redox cycling was proved electrochemically by in situ treatments of La0.85Sr0.15Cr0.9Ni0.1O3−δ electrode. Materials were further analyzed by TPR and XPS (in oxidized and reduced state) in order to identify the possible species involved in the electrocatalytic processes.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Catalysts including La1−xSrxCr1−yNiyO3−δ (x = 0, 0.15; y = 0.05, 0.1, 0.2) were prepared and tested. ► The electrochemical test (EIS) anode was done using both H2 and CH4 as fuels on YSZ electrolyte. ► Structural and redox evolution was monitored by XRD, TEM and XPS in oxidized and reduced samples. ► Upon reduction the perovskite structure is kept and metallic nickel nanoparticles are formed.

Keywords
Anode; Chromites; Redox cycle; Nickel; Nanoparticle; Redox cycling; Methane steam reforming
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Redox stability and electrochemical study of nickel doped chromites as anodes for H2/CH4-fueled solid oxide fuel cells
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 115–116, 5 April 2012, Pages 346–356
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us