Khalipova, Olga S.

Lair, V.

Ringuedé, A.

English

Tomsk State University Repository

МИНИСТЕРСТВО ОБРАЗОВАНИЯ И НАУКИ РОССИЙСКОЙ ФЕДЕРАЦИИ Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования «НАЦИОНАЛЬНЫЙ ИССЛЕДОВАТЕЛЬСКИЙ ТОМСКИЙ ПОЛИТЕХНИЧЕСКИЙ УНИВЕРСИТЕТ»       ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК   Сборник научных трудов X Международной конференция студентов и молодых ученых    РОССИЯ, ТОМСК, 23–26 апреля 2013 г.    PROSPECTS OF FUNDAMENTAL SCIENCES DEVELOPMENT   X INTERNATIONAL CONFERENCE OF STUDENTS AND YOUNG SCIENTISTS   RUSSIA, TOMSK, April 23–26, 2013        Томск 2013  X МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ И МОЛОДЫХ УЧЕНЫХ «ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК»                                                           471 РОССИЯ, ТОМСК, 23 – 26 АПРЕЛЯ 2013 г.         ХИМИЯ СПИСОК ЛИТЕРАТУРЫ  1. Надиров Н.К. Высоковязкие нефти и природные битумы. – Алматы: Изд-во Гылым, 2001. – 415 с.  2. Оборин А.А., Иларионов С.А. Нефтезагрязненные биоценозы. – Пермь.: Изд-во ПГУ, 2008. – 511 с. 3. Другов Ю.С., Родин А.А. Анализ загрязненной почвы и опасных отходов. Практическое руководство. – М.: Изд-во Бином, 2007. – 263 с.     ЭЛЕКТРОХИМИЧЕСКИЙ СИНТЕЗ И ХАРАКТЕРИСТИКАТОНКИХ ПЛЕНОК  CeO2–Gd2O3 О.С. Халипова1, В. Лэр2, A. Рэнгдэ2 Научный руководитель: доктор A. Рэнгдэ2 1Tомский государственный университет, Россия, г. Томск, пр. Ленина, 36, 634050 1Лаборатория электрохимии, химии межфазных поверхностей и моделяции для энергетики, Школа химии Paristech, Париж, улица Пьера и Мари Кюри, 11, 75231код 05 E-mail: Chalipova@mail.ru  ELECTROCHEMICAL SYNTHESIS AND CHARACTERIZATION OF CeO2–Gd2O3THIN FILMS O.S. Khalipova1, V. Lair2, A. Ringuedé2 Scientific Supervisor: Dr.  A. Ringuedé2 1Tomsk State University, Russia, Tomsk, Lenin str., 36, 634050 2Laboratoire d’Electrochimie, Chimie des Interfaces et Modélisation pour l’Énergie, Chimie Paristech, France, 11rue Pierre et Marie Curie, 75231 Paris cedex 05 E-mail: Chalipova@mail.ru  Тонкие пленки CeO2иGd2O3былиполученыметодомэлектроосаждения из водных растворов с различнойконцентрациейнитратовСе(III) иGd(III), при различном времени осажденияи комнатной температуре. Комбинируя условия синтеза обоих одиночных оксидов, Gd-допированные пленки церия были получены на подложках из нержавеющей стали. Структура и морфология электроосажденных пленок были изучены методами рентгенофазового анализа, сканирующей электронной микроскопии и спектроскопией комбинационного рассеивания.   Cerium oxide (CeO2) is a material of special interest due to its wide applications as a promoter or support in three-way catalysts (TWCs) [1], gas sensors [2], optical coatings [3], etc.  In the recent past years ceria doped with rare-earth oxides are intensively investigated for application as a solid electrolyte in solid oxide fuel cells (SOFC) [4] because of their much higher ionic conductivity at lower temperatures compared to the conventional electrolyte material of yttria-stabilized zirconia (YSZ), that allows to use cheaper SOFC components or to overcome fast ageing for instance [5]. It was shown that one of the best dopant is gadolinium, due to its optimum atomic radius and the resulting higher ionic conductivity [6]. Many research articles in literature are dedicated to prepare the doped ceria by variety of methods such as atomic layer deposition [7], laser beam evaporation ion [8], sol–gel processing [9], etc. Among these numerous deposition techniques, which are relatively complex, X МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ И МОЛОДЫХ УЧЕНЫХ «ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК»                                                           472 РОССИЯ, ТОМСК, 23 – 26 АПРЕЛЯ 2013 г.         ХИМИЯ expensive and require high temperature, long heat treatment, etc., electrochemical deposition is a less onerous one, already used in industry and research, owing to its simplicity, easy scale–up (large area substrate) and high quality film. This work deals with the electrodeposition of CeO2–Gd2O3 films and the influence of synthesis parameters on their morphology, thickness and composition. Ceria, gadolinia and gadolinium–doped cerium oxide films were prepared using a classical three-electrode set–up for the electrodeposition: stainless steel disc as working electrode, saturated calomel electrode as reference, and platinum wire as counter–electrode. The substrate (stainless steel 316L) was cleaned in ethanol before deposition. The electrolyte was composed by Ce(NO3)3·6H2O (0,01 M–0,001 М) with or without addition of Gd(NO3)3·5H2O (0,005 M–0,0001 M) and with 0,1 M NaNO3 as supporting electrolyte. For the fabrication of pure gadolinium films, the electrolytic solution contained Gd(NO3)3·5H2O (0,01 М–0,001 М) in addition to the same supporting electrolyte. The solutions were saturated with molecular oxygen for 30 min before starting the experiment, and a slight O2 bubbling in the reactor was maintained during the growth process. Films were deposited applying a −0,7 V/SCE to –0,9 V/SCE potential. Deposition time ranged from 5 min to 30 min. After deposition, samples were rinsed in deionized water. Thermal annealing was done at 600 °C for 1 h, in air, with a heating rate of 2 °C per minute. The films were characterized by different methods. The structural characterization was performed using X-ray diffraction (XRD) and Raman spectroscopy. XRD was performed using Siemens D5000 instrument with Cu Kα radiation. Micro-Raman spectra were measured at room temperature with a Horiba Jobin system (HR800 UV) using line 632,8 nm of He–Ne laser. The morphology of the films was studied by scanning electron microscopy (SEM). Images were made with a high resolution Ultra 55 Zeiss FEG scanning electron microscope.  The X-ray diffraction patterns confirm that the solid solutions of CeO2−Gd2O3 were formed after calcination at 600°C the films which were deposited from electrolytic solutions containing Gd(NO3)3·5H2O and Ce(NO3)3·6H2O with different concentrations, regardless of the process time.  SEM showed observation that morphology and thickness of all as-grown films depends on composition of electrolytic solutions, time of deposition and annealing. At first sight, the films seem to fully cover the surface, as bare substrate is not visible, but on closer inspection there are cracks in the films. The cracks observed in the film are most likely due to shear stresses between oxide film and stainless steel substrate (during oxidation step or/and drying step) [4]. In comparison with the pure as-grown ceria or gadolinium films, the Gd−doped ceria shows much more compact and denser morphology (Inlets in Fig. 1.). During the work, it has been observed that the film's thickness increases with higher concentration of solutions and time of deposition, while it decreases after annealing because of sintering Fig. 1.Raman spectra of pure ceria, pure gadolinia and Gd–doped ceria after calcination at 600°C, 1h in air. Substrate spectrum is given as a reference. Inlets: SEM micrographs of a) pure gadolinia; b) pure ceria and c) Gd–doped ceria films. X МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ И МОЛОДЫХ УЧЕНЫХ «ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК»                                                           473 РОССИЯ, ТОМСК, 23 – 26 АПРЕЛЯ 2013 г.         ХИМИЯ effect, thus higher compactness.  All CeO2−Gd2O3 films deposited on stainless steel were investigated by Raman spectroscopy before and after calcinations. This highly sensitive and non-destructive technique is extremely powerful especially for fast analysis of the phase and relative thickness of samples, and also it can be used to study dopant incorporation. To confirm the formation of gadolinium-doped ceria solid solution, Raman spectra were obtained for pure gadolinium and pure ceria based films (Fig. 1a and Fig. 1b). There is a clear vibrational mode at 475cm−1, which is typical of CeO2 and corresponds to the F2g symmetry, which confirms the formation of CeO2 phase after heat treatment. The formation of a cubic structure of gadolinium films before calcination of samples wasn't further supported by Raman spectroscopy. The vibrational mode at 370cm−1 corresponding to Gd2O3 cubic phase was observed only after calcination of samples, but not anymore for the Gd–doped ceria film. The shift of the 475cm−1 peak to the lowest wave number and its shape confirm the solid solution [4]. The original result of this work is the fabrication from only one electrolytic solution of their Gd–doped ceria films by electrochemical technique. Raman spectroscopy and X-ray diffraction studies clearly shown that solid solution of Gd–doped ceria was obtained, in a cubic structure.  Acknowledgements: S. Borensztajn from the laboratory LISE(UPR 15) for SEM analysis; Tomsk state university for the grand allowing me to perform this study in France.   REFERENCES  1. Kaspar J., Fornasiero P., Graziani M. Use of CeO2−based oxides in the three−way catalysis // Catalysis Today. – 1999. – V. 50. – № 2. – P. 285–298. 2. Jasinski P., Suzuki T., Anderson H.U. Nanocrystalline undoped ceria oxygen sensor // Sensors and Actuators. B, Chemical. – 2003. – V. 95. - № 1–3. – P. 73 – 77. 3. Jiang Y., Bahlawane N. Changes in the structural and optical properties of CeO2 nanocrystalline films: effect of film thickness // Journal of Alloys and Compounds. – 2009. – V. 485. – P. 152–155.   4. Lair V., Zivkovic L.S., Lupan O., Ringuede A.  Synthesis and characterization of electrodeposited samaria and samaria−doped ceria thin films // Electrochimica Acta. – 2011. – V. 56. – P. 4638–4644.  5. Ursaki V.V., Lair V., Zivkovic L., Cassir M., Ringuede A., Lupan O. Optical properties of Sm−doped ceria nanostructured films grown by electrodeposition at low temperature // Optical Materials. – 2012. – V. 34. – P. 1897–1901. 6. Burinskas S., Adomonis V., Dudonis J., etcSynthesis and characterization of GDC solid electrolytes obtained by solid state sintering of multilayer thin films // Solid State Ionics. – 2011. – V. 184. – P. 14–18.  7. Cassir M., Ringuedé A., Niinistö L. Input of atomic layer deposition for solid oxide fuel cell applications // J. Materials Chemistry. – 2010. – V. 20. – P. 8987–8993.  8. Laukaitis G., Dudonis J.  Microstructure of gadolinium doped ceria oxide thin films formed by electron beam deposition // Journal of Alloys and Compounds. – 2008. – V. 459. – P. 320–327.  9. Skofic I.K., Sturm S., Ceh M., Bukovec N. CeO2 thin films obtained by sol–gel deposition and annealed in air or argon // Thin Solid Films. – 2002. – V. 422. – P. 170–175.    

Electrochemical synthesis and characterization of CeO2–Gd2O3 thin films

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Electrochemical synthesis and characterization of CeO2–Gd2O3 thin films

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