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Vanadia-silica aerogels from vanadylacetylacetonate

机译:钒氧乙酰丙酮化物的钒硅气凝胶

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For the preparation of vanadium pentoxide doped silica gels, vanadium(V) oxide trialkoxides are the precursors of choice [A.E. Stiegman H. Eckert, G. Plett, S.S. Kim, M. Anderson, A. Yavrouia, Chem. Mater. 5 (11) (1993) 1591; D.C.M. Dutoit, M. Schneider, P. Fabrizioli, A. Baiker. Chem. Mater. 8 (1996) 734] as they possess already the desired oxidation number. Ln vanadylacetylacetonate, the oxidation number of vanadium is only +4 instead of +5. However, vanadylacetylacetonate is less reactive with water and thus easier to handle, less toxic and cheaper than vanadium(V) oxide triisopropoxide. Gels were prepared using vanadylacetylacetonate, tetramethoxysilane, methanol and water containing HCl or NH3 as catalyst. After supercritical drying with respect to CO2 and heat treatment in air, vanadia doped silica aerogels show the same colour change upon adsorption of water molecules as vanadium(V) oxide triisopropoxide doped silica xerogels. Structural properties were investigated by N-2-absorption and SAXS measurements. (C) 1998 Elsevier Science B.V. All rights reserved. [References: 5]
机译:为了制备五氧化二钒掺杂的硅胶,选择三氧化二钒(V)是前体[A.E. Stiegman H.Eckert,G.Plett,S.S。Kim,M.Anderson,A.Yavrouia,Chem。母校5(11)(1993)1591;直流电Dutoit,M。Schneider,P。Fabrizioli,A。Baiker。化学母校8(1996)734],因为它们已经具有所需的氧化数。钒基乙酰丙酮锡,钒的氧化数仅为+4而不是+5。但是,相比于三氧化二钒钒,乙酰丙酮氧钒与水的反应性较低,因此更易于处理,毒性较小且便宜。使用钒基乙酰丙酮酸酯,四甲氧基硅烷,甲醇和含有HCl或NH3的水作为催化剂制备凝胶。在对二氧化碳进行超临界干燥并在空气中进行热处理后,掺杂钒的二氧化硅气凝胶在吸附水分子时显示出与掺杂钒(V)的三异丙醇氧化物的二氧化硅干凝胶相同的颜色变化。通过N-2-吸收和SAXS测量研究了结构性质。 (C)1998 Elsevier Science B.V.保留所有权利。 [参考:5]

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