Oxygen chemical potential variation in ceria-based solid oxide fuel cells determined by Raman spectroscopy

Mineshige, Atsushi; Taji, Toshiya; Muroi, Yasunori; Kobune, Masafumi; Fujii, Satoshi; Nishi, Naoya; Inaba, Masaaki; Ogumi, Zempachi

doi:10.1016/s0167-2738(00)00403-3

Cited by 101 publications

(58 citation statements)

References 15 publications

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“…In this structure, cerium cations are located at the corners and center of the faces of a cubic unit cell and oxygen anions are placed in the octahedral positions. The F2g band is related to the oxygen anions' vibration around the octahedral position [14,15].…”

Section: Characterization Of the Catalysts' Crystallinity By Raman Spmentioning

confidence: 99%

Improved CO Oxidation Activity of 3DOM Pr-Doped Ceria Catalysts: Something Other Than an Ordered Macroporous Structure

et al. 2017

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Abstract:It is demonstrated that the synthesis procedure for preparing three-dimensionally ordered macroporous (3DOM) Pr-doped ceria catalysts using a polymethylmethacrylate (PMMA) template not only affects the porous structure, but also the chemistry of the ceria surface. The PMMA template does not affect the crystalline features (type of phases, crystallite size, and cell parameter) of Pr-doped ceria, Ce and Pr location into the particles, and the bulk reduction of the Ce-Pr mixed oxide catalysts. On the contrary, the utilization of the PMMA template improves both the porosity and surface redox properties. 3DOM Ce-Pr mixed oxide catalysts combine micro, meso, and macropores, the most area being in the macropore range, while a reference unshaped catalyst presents poor porosity in all ranges. However, the catalyzed CO oxidation rates do not correlate with the surface area of the catalysts (neither micro nor meso/macro). The Ce-Pr-3DOM catalyst also presents improved surface reducibility with regards to the counterpart reference material prepared without the template, and improved redox behavior under reaction conditions; that is, it has a higher area and this area is reduced and reoxidized more easily. X-ray photoelectron spectroscopy analysis evidences that this is mainly attributed to praseodymium cations, which accomplish redox cycles more easily than cerium cations.

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Section: Characterization Of the Catalysts' Crystallinity By Raman Spmentioning

confidence: 99%

Improved CO Oxidation Activity of 3DOM Pr-Doped Ceria Catalysts: Something Other Than an Ordered Macroporous Structure

et al. 2017

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“…A slight peak shift to a lower wavenumber (454 cm -1 ) was observed in the film prepared in the mixed solution, suggesting that the heavier Sm 3+ was present in the CeO 2 lattice [34]. Additionally, the broad peak at 500 ~ 650 cm -1 that appeared was related to the oxygen defects which originated from the partial substitution of Sm 3+ for Ce 4+ , i.e., Ce 1-x Sm x O 2-y [35]. These results demonstrated that the electrochemical growth of the CeO 2 layer together with Sm under a cathodic potential induces the incorporation of Sm 3+ into the CeO 2 lattice in a manner similar to the coprecipitation method for the powder synthesis of doped ceria.…”

Section: Crystal Structure Of As-deposited Filmmentioning

confidence: 93%

Optimization of electrochemical synthesis conditions for dense and doped ceria thin films

Kamada¹,

Enomoto²,

Hojo³

2009

Electrochimica Acta

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In the present study, the appropriate electrolysis conditions were determined for attaining doped ceria thin films with a high density and adhesion in an aqueous solution containing of Ce 3+ and Sm 3+ ions. Based on a comparison of the anodic and cathodic polarizations, while the former only induced the deposition of Ce 3+ , the latter accomplished the simultaneous deposition of Ce and Sm species. Under an applied cathodic bias below the hydrogen evolution potential, the Ce 3+ and Sm 3+ were reacted with OH -ions generated by the reduction of water molecules, and then were deposited on the electrode as a hydroxide. The hydroxide was subsequently oxidized and dehydrated to form the ceria-based thin layer. The morphologies of the as-deposited films were significantly altered on the basis of the applied potential. Moreover, the addition of acetic acid to the electrolysis bath caused the production of a transparent, dense, and adherent film. The XRD pattern and Raman spectrum of the thin film revealed that the film was crystallized as the fluorite structure without any heat treatment, and Sm 3+ is substituted at the Ce 4+ site. Moreover, the Sm content in the film could be easily controlled by the metal concentration in the solution.

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“…The three Ce0.64Zr0.27Nd0.09O δ catalysts show an intense band around 465 cm -1 characteristic of the cubic fluorite structure of ceria [36], which is in accordance with the X-ray diffractograms (Figure 4), and another band or shoulder at 560-590 cm -1 that can be attributed to oxygen vacant sites created on the mixed oxide lattice [37]. The actual position of the main ceria band is in fact lower than -1 for all Ce0.64Zr0.27Nd0.09O δ catalysts, which is the typical value for plane ceria.…”

Section: Analysis Of Zr and Nd Doping Into The Ceria Lattice By Ramanmentioning

confidence: 96%

Effect of the CeZrNd mixed oxide synthesis method in the catalytic combustion of soot

2015

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Ce0.64Zr0.27Nd0.09O δ mixed oxides have been prepared by three different methods (nitrates calcination, coprecipitation and microemulsion), characterized by N2 adsortion, XRD, H2-TPR, Raman spectroscopy and XPS, and tested for soot combustion in NOx/O2. The catalyst prepared by microemulsion method is the most active one, which is related to its high surface area (147 m 2 /g) and low crystallite size (6 nm), and the lowest activity was obtained with the catalyst prepared by coprecipitation (74 m 2 /g; 9 nm). The catalyst prepared by nitrates precursors calcination is slightly less active to that prepared by microemulsion but the synthesis procedure is very straightforward and surfactants or other chemicals are not required, being very convenient for scaling up and practical utilization. The high activity of the catalyst prepared by nitrates calcination can be attributed to the better introduction of Nd cations into the parent ceria framework than on catalysts prepared by coprecipitaion and microemulsion, which promotes the creation of more oxygen vacancies.

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Oxygen chemical potential variation in ceria-based solid oxide fuel cells determined by Raman spectroscopy

Cited by 101 publications

References 15 publications

Improved CO Oxidation Activity of 3DOM Pr-Doped Ceria Catalysts: Something Other Than an Ordered Macroporous Structure

Improved CO Oxidation Activity of 3DOM Pr-Doped Ceria Catalysts: Something Other Than an Ordered Macroporous Structure

Optimization of electrochemical synthesis conditions for dense and doped ceria thin films

Effect of the CeZrNd mixed oxide synthesis method in the catalytic combustion of soot

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