Synthesis and characterization of electrodeposited samaria and samaria-doped ceria thin films

Samaria (Sm2O3) and samaria-doped ceria (SDC) films are electrochemically deposited on stainless steel in view of a potential use in solid oxide fuel cells. As it is possible to deposit separately pure ceria (CeO2) and pure samaria (Sm2O3) in similar conditions, SDC films were successfully obtained in one electrochemical conditions set. Thin films have been fabricated at low-temperature (30 degrees C) by applying a cathodic potential of -0.8 V/SCE, for 2 h. Structural and morphological properties of electrodeposited films have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), techniques and Raman spectroscopy. Special attention has been focused on the Raman spectroscopy study to emphasize the effect of heat treatment and samarium doping. Despite cracks, single SDC phase was obtained crystallizing in a cubic symmetry. (C) 2011 Elsevier Ltd. All rights reserved

Effect of samarium addition and annealing on the properties of electrodeposited ceria thin films

Samarium (Sm)-doped ceria (CeO2) (SDC) is a promising material for high temperature electrochemical devices. Our work demonstrates that thin SDC films can be prepared by a cost-effective electrodeposition method at a low-temperature (30 degrees C) and -0.8 V/SCE (saturated calomel electrode) potential. Analysis of the structural properties of the obtained SDC films, as-grown and annealed at 600 degrees C, has been carried out by X-ray diffraction (XRD). Morphology and film composition were studied using scanning electronic microscopy and energy dispersive X-ray analysis. Vibrational properties were determined by Raman spectroscopy. The effects of samarium addition into the deposition bath on the final film composition have been studied. According to XRD results, film crystallographic properties are directly linked to the percentage of Sm incorporated in the CeO2 lattice. We report on the electrochemical deposition of the SDC films performed over a large range of Sm additions (0-30%). The effect of temperature annealing has been studied as well. (C) 2011 Elsevier B.V. All rights reserved

Electrochemical synthesis and properties of ceria films grown on stainless steel

Electrochemical synthesis of ceria films was performed on a stainless steel substrate in view of Solid Oxide Fuel Cells (SOFC) applications. Films were obtained from aqueous nitrate solutions via cathodic deposition method at room temperature. A constant potential value of -0.8 V/(SCE) was applied to reduce the molecular oxygen as hydroxide precursor, leading to a formation of adherent, homogeneous and covering films in 20 min deposition time. Structure, morphology and composition of as-grown coatings were studied by X-ray diffraction, Raman and energy-dispersive X-ray spectroscopy, as well as scanning electron microscopy. Cubic fluorite-type nanostructured ceria of leaf-like particles was synthesized. Thermal annealing (600A degrees C, 1 h) was found to enhance ceria crystallinity

Samarium-Doped Ceria Nanostructured Thin Films Grown on FTO Glass by Electrodepostion

Electrical, optical or catalytic properties of ceria can be tuned via doping by rare earth elements. The innate properties of ceria-based materials can be further amplified by using nanostructured ceria. In this study, Sm-doped ceria (SDC) coatings were grown on the FTO glass substrate by means of cathodic deposition. Films were obtained from mixed Sm3+/Ce3+ aqueous nitrate solutions, applying -0.8V/(SCE) potential for 1 h. Selected conditions gave rise to adherent, homogeneous and well-covering nanostructured SDC thin films. EDX analysis showed that 0.8 and 1.5 mol% Sm3+ led to 3.4 and 6.3 at.% Sm in the SDC films. XRD and Raman analysis confirmed the formation of cubic fluorite-type CeO2. However, Sm-doping decreased the crystallite size of nanostructured ceria. The effect of annealing on SDC film was also studied. An improvement in crystallite quality was found with increasing temperature. Optical absorption properties were studied and the band gap value (E-g) of 3.07 eV was determined for pure ceria. Sm-doped ceria exhibited a red shifting. The E-g values were 2.97 and 2.81 eV, in due order.12th Annual YUCOMAT Conference, Sep 06-10, 2010, Herceg Novi, Montenegr

Optical properties of Sm-doped ceria nanostructured films grown by electrodeposition at low temperature

Nanostructured undoped and samarium doped ceria thin nanocolumnar films are electrodeposited onto (FTO) glass substrates at low-temperature (30 degrees C) with a subsequent thermal annealing at 600 degrees C for 1 h. Films are obtained from mixed Sm3+/Ce3+ aqueous nitrate solutions, applying a -0.8 V/(SCE) potential for 1 h. Cubic fluorite type ceria nanostructured films of high crystal quality are synthesized as confirmed by X-ray diffraction and Raman spectroscopy. SEM analysis demonstrates that doping with Sm improves the quality of the film with respect to crack formation. The incorporation and activation of the Sm3+ ions in the ceria host as well as the Stark splitting of the manifolds responsible for emission in the red-orange spectral range are investigated by means of photoluminescence spectroscopy. (C) 2012 Elsevier B.V. All rights reserved

Design, Synthesis, Structural and Textural Characterization, and Electrical Properties of Mesoporous Thin Films Made of Rare Earth Oxide Binaries

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MnCo1.9Fe0.1O4 Spinel Protection Layer on Commercial Ferritic Steels for Interconnect Application in SOFC

In solid oxide fuel cells (SOC) for operating temperatures of 800 degrees C or below, the interconnection plates can be made from stainless steel. This is a big economic advantage, but energy losses can be caused by undesirable reactions between the alloys and other SOFC components. The use of coatings on interconnect stainless steels can reduce this degradation. A MnCo1.9Fe0.1O4(MCF) spinel not only significantly decreases the contact resistance between a La0.8Sr0.2FeO3 cathode and a stainless steel interconnect, but also acts as a diffusion barrier to prevent Cr outward migration through the coating. The level of improvement in electrical performance depends on the ferritic substrate composition. For Crofer22APU and F18TNb, with a Mn concentration of 0.4 and 0.12wt%, respectively, the reduction in contact resistance is significant. In comparison, limited improvement is achieved by application of MCF on IT-11 and E-Brite containing no Mn. No influence of the minor additions of Si or Al is observed on contact resistance. The MCF protection layer bonds well to the stainless steel substrates under thermal cycling, but the thermal expansion difference is too large between the La0.8Sr0.2Co0.75Fe0.25O3 contact layer used and Crofer22APU and IT-11. (C) 2008 Elsevier B.V. All rights reserved