Zirconia-based Aerogels via Hydrolysis of Salts and Alkoxides: The Influence of the Synthesis Procedures on the Properties of the Aerogels

Authors

  • Dr. Helmut Schäfer,

    Corresponding author
    1. University of Osnabrück, Institute of Chemistry of New Materials, Physical Chemistry, Barbarastraße 7, 49069 Osnabrück (Germany)
    • Helmut Schäfer, University of Osnabrück, Institute of Chemistry of New Materials, Physical Chemistry, Barbarastraße 7, 49069 Osnabrück (Germany)

      Lorenz Ratke, German Aerospace Center, Institute of Materials Physics in Space, Linder Höhe, 51147 Cologne (Germany)

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  • Susanne Brandt,

    1. German Aerospace Center, Institute of Materials Physics in Space, Linder Höhe, 51147 Cologne (Germany)
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  • Dr. Barbara Milow,

    1. German Aerospace Center, Institute of Materials Physics in Space, Linder Höhe, 51147 Cologne (Germany)
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  • Sachar Ichilmann,

    1. University of Osnabrück, Institute of Chemistry of New Materials, Physical Chemistry, Barbarastraße 7, 49069 Osnabrück (Germany)
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  • Prof. Dr. Martin Steinhart,

    1. University of Osnabrück, Institute of Chemistry of New Materials, Physical Chemistry, Barbarastraße 7, 49069 Osnabrück (Germany)
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  • Prof. Dr. Lorenz Ratke

    Corresponding author
    1. German Aerospace Center, Institute of Materials Physics in Space, Linder Höhe, 51147 Cologne (Germany)
    • Helmut Schäfer, University of Osnabrück, Institute of Chemistry of New Materials, Physical Chemistry, Barbarastraße 7, 49069 Osnabrück (Germany)

      Lorenz Ratke, German Aerospace Center, Institute of Materials Physics in Space, Linder Höhe, 51147 Cologne (Germany)

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Abstract

This contribution aims at evaluating different synthesis procedures leading to zirconia-based aerogels. A series of undoped and yttrium-doped zirconia aerogels have been prepared via hydrolysis and condensation reaction of different alkoxy- and different inorganic salt-based precursors followed by supercritical drying. Well-established but deleterious zirconium n-propoxide (TPOZ) or zirconium n-butoxide (TBOZ) were used as metal precursors in combination with acids like nitric acid and acetic acid as auxiliary agent for the generation of non-yttrium stabilized zirconia aerogels. Yttrium-stabilized zirconia aerogels as well as pure zirconia aerogels were obtained by the salt route starting from ZrCl4 and crosslinking agents like propylene oxide or acetylacetone. The characteristics of the products were analyzed by nitrogen adsorption measurements, electron microscopy, and X-ray scattering. It turned out that with respect to all relevant properties of the aerogels as well as the practicability of the synthesis procedures, approaches based on inexpensive non-toxic salt precursors are the methods of choice. The salt-based approaches allow not only for low-cost, easy-to-handle synthesis procedures with realizable gelation times of less than 60 seconds, but also delivered the products with the highest surface area (449 m2 g−1 for ZrCl4) within this series of syntheses.

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