Porous CeOX/SiC nanocomposites prepared from reverse polycarbosilane-based microemulsions

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

  • Emanuel Kockrick - , Technische Universität Dresden (Autor:in)
  • Piotr Krawiec - , Technische Universität Dresden (Autor:in)
  • Uwe Petasen - , Fraunhofer Institute for Ceramic Technologies and Systems (Autor:in)
  • Hans Peter Martin - , Fraunhofer Institute for Ceramic Technologies and Systems (Autor:in)
  • Mathias Herrmann - , Fraunhofer Institute for Ceramic Technologies and Systems (Autor:in)
  • Stefan Kaskel - , Professur für Anorganische Chemie (I) (AC1) (Autor:in)

Abstract

Reverse microemulsions consisting of aqueous cerium nitrate solution as the internal phase and polycarbosilane dissolved in heptane as the continuous phase were used as a precursor for the controlled synthesis of dispersed cerium oxide particles inside a porous SiC matrix. According to dynamic light scattering experiments, the effective diameter of the cerium hydroxide particles obtained after ammonia addition is effectively controlled in a range of 2-10 nm with the molar water/surfactant ratio (Rw = 6-16). Pyrolysis at 1200 to 1500°C produces materials with specific surface areas up to 240 m 2 g-1. Whereas crystallization of the matrix is achieved only at higher temperature, cerium oxide particles form agglomerates composed of smaller nanoparticles that tend to dissolve into the ceramic matrix at 1500°C leaving macropores behind. The high specific surface area is attributed to the presence of mesopores with a broad size distribution. Excess carbon present after pyrolysis is removed by oxidation at 900°C causing a significant decrease of the surface area for high surface area materials, whereas intermediate surface area materials (50-100 m2 g -1) show a high textural stability.

Details

OriginalspracheEnglisch
Seiten (von - bis)77-83
Seitenumfang7
FachzeitschriftChemistry of materials
Jahrgang20
Ausgabenummer1
PublikationsstatusVeröffentlicht - 8 Jan. 2008
Peer-Review-StatusJa