Coupling in situ synchrotron radiation with ex situ spectroscopy characterizations to study the formation of Ba_{1鈭?span style='font-style: italic'>x}Sr_xTiO₃ nanoparticles in supercritical fluids

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• 作者：Gilles Philippot^a ; Kirsten M.Ø ; . Jensen^b ; Mogens Christensen^b ; Catherine Elissalde^a ; Mario Maglione^a ; Bo B. Iversen^b ; ^{bo@chem.au.dk" class="auth_mail} ; Cyril Aymonier^a ; ^{aymonier@icmcb-bordeaux.cnrs.fr" class="auth_mail}
• 关键词：Barium strontium titanate ; Supercritical fluids ; In situ ; Synchrotron WAXS ; Growth mechanism
• 刊名：The Journal of Supercritical Fluids
• 出版年：March, 2014
• 年：2014
• 卷：87
• 期：Complete
• 页码：111-117
• 全文大小：1804 K

文摘

High quality barium strontium titanate (Ba_xSr_{1 鈭?#xA0;x}TiO₃ with 0 鈮?#xA0;x 鈮?#xA0;1-BST) nanoparticles can be synthesized using supercritical fluids technology. Well crystallized particles of 20 nm with a narrow size distribution were produced in a single step. The reaction is achieved at relatively low temperature (T < 400 掳C) and in tens of seconds. The combination of in situ synchrotron wide angle X-ray scattering (WAXS) and ex situ analyses in the form of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM) leads to an understanding of the influence of the substitution of barium cations with strontium ones on the BST nanoparticle growth. A correlation between particle size, density of -OH groups at the surface of the particles and BST composition is exhibited; the higher the -OH density and the lower the strontium concentration, the larger the particles. This confirms that the formation of BST nanoparticles in supercritical fluids is governed by a sol-gel mechanism.