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Formation of Hierarchically Porous Metal Oxide and Metal Monoliths by Nanocasting into Silica Monoliths

Authors

  • Jan-Henrik Smått,

    Corresponding author
    1. Center for Functional Materials and Laboratory of Physical Chemistry, Åbo Akademi University, Porthansgatan 3-5, FIN-20500, Turku, Finland
    • Center for Functional Materials and Laboratory of Physical Chemistry, Åbo Akademi University, Porthansgatan 3-5, FIN-20500, Turku, Finland.
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  • Franchessa M. Sayler,

    1. Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487-0336, USA
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  • Amy J. Grano,

    1. Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487-0336, USA
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  • Martin G. Bakker

    Corresponding author
    1. Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487-0336, USA
    • Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487-0336, USA.
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  • Support for this work was provided by NSF CHE-0719398 (MGB) and by the Academy of Finland 127919 (JHS). Electron microscopy was carried out in the Central Analytical Facility at The University of Alabama. Mika Lindén (University of Ulm) is gratefully acknowledged for valuable discussion, as are Mikael Järn (Åbo Akademi University) for SEM measurements (SiO2 and ZrO2) and Bernd Spliethoff (MPI, Mülheim an der Ruhr) for TEM measurements (SiO2 and ZrO2). Keana Graves (Fe2O3), Alison Hu (Ni and NiO), and Elizabeth Junkin (Co3O4) provided technical assistance with sample preparation. Supporting Information is available from the Wiley Online Library or from the authors.

Abstract

The formation of hierarchically porous metal and metal oxide monoliths by replication of hierarchically porous silica templates is reviewed. The various factors that impact the structure and properties of the synthesized materials are discussed and illustrated by the formation of new α-Fe2O3, ZrO2, nickel, silver, and silver silicate porous monoliths. The impact of the atmosphere is addressed in the formation of Co3O4 and silver monoliths. For Co3O4, formation of the monolith under vacuum, air, argon, or nitrogen was found to dramatically change the structure of the final material. For silver, decomposition of the silver nitrate under air resulted in porous monoliths composed of silver silicates. Decomposition of silver nitrate under vacuum produced monoliths for which the chemical composition of the monolith was predominantly silver on the exterior of the monolith consisted of silver silicates in the interior of the monolith.

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