Letter abstract
Nature Materials 2, 386 - 390 (2003)
Published online: 25 May 2003 | doi:10.1038/nmat903
Subject Categories: Metals and alloys | Porous materials | Design synthesis and processing
Dextran templating for the synthesis of metallic and metal oxide sponges
Dominic Walsh1, Laura Arcelli2, Toshiyuki Ikoma3, Junzo Tanaka3 & Stephen Mann1
Silver or gold-containing porous frameworks have been used extensively in catalysis, electrochemistry, heat dissipation and biofiltration1, 2, 3. These materials are often prepared by thermal reduction of metal-ion-impregnated porous insoluble supports (such as alumina and pumice), and have surface areas of about 1 m2 g-1, which is typically higher than that obtained for pure metal powders or foils prepared electrolytically4 or by infiltration and thermal decomposition of insoluble cellulose supports5. Starch gels have been used in association with zeolite nanoparticles to produce porous inorganic materials with structural hierarchy6, but the use of soft sacrificial templates in the synthesis of metallic sponges has not been investigated. Here we demonstrate that self-supporting macroporous frameworks of silver, gold and copper oxide, as well as composites of silver/copper oxide or silver/titania can be routinely prepared by heating metal-salt-containing pastes of the polysaccharide, dextran, to temperatures between 500 and 900 °C. Magnetic sponges were similarly prepared by replacing the metal salt precursor with preformed iron oxide (magnetite) nanoparticles. The use of dextran as a sacrificial template for the fabrication of metallic and metal oxide sponges should have significant benefits over existing technologies because the method is facile, inexpensive, environmentally benign, and amenable to scale-up and processing.
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
- Department of Chemistry, University of Perugia, Via Elce di Solto 8, I-06123 Perugia, Italy
- National Institute for Materials Science, Biomaterials Center, 305-0044 Namiki 1-1, Tsukuba, Ibaraki, Japan
Correspondence to: Stephen Mann1 e-mail: s.mann@bristol.ac.uk
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