Sol-Gel Synthesis Assisted by Supercritical CO₂ - A Flexible Process for Ceramic Powder and Membrane Preparation

Abstract:

The increasing interest in supercritical fluids for synthesizing inorganic materials stimulated the development of new processes for production of nanophased powders/layers with controlled characteristics. Original processes based on sol-gel synthesis assisted by supercritical CO2 have been developed. Unusual powder structures/morphologies have been evidenced and cosolvent characteristics have been proved to influence powder specific surface area and crystallite sizes. The development of a new semi-continuous process also enabled to tailor powder morphology by controlling hydrodynamic parameters (injection speed and stirring rate). Especially, yttria-stabilized zirconia prepared with this method are composed of 5-7 nm crystallites aggregated in spherical nanoparticles (<100nm) and yielding particularly high specific surface areas (up to 250 m2/g). These YSZ powders can be compacted/deposited and sintered to prepare nanosized dense membranes for ionic conduction. Finally, SC-CO2 sol-gel processes can also be adapted to directly prepare gas separation membranes. In particular, an innovative process has been developed to coat tubular porous ceramic substrates with porous silica-based layer.

• Periodical: Advances in Science and Technology (Volume 62)
• Pages: 113-118
• DOI: https://doi.org/10.4028/www.scientific.net/AST.62.113
• Online since: October 2010
• Authors: Audrey Hertz, Véronique Durand, Stéphane Sarrade, Christian Guizard, Anne Julbe, Jean-Christophe Ruiz, Frédéric Charton
• Keywords: Dense Membrane, Gas Separation, Ionic Conducting Ceramic, Porous Membrane, Sol-Gel Process, Supercritical CO₂

References

[1] C. Guizard, A. Julbe, O. Robbe and S. Sarrade: Catalysis Today Vol 104 (2005), p.120.

DOI: 10.1016/j.cattod.2005.03.046

[2] A. Hertz, Y. -M. Corre, S. Sarrade, C. Guizard, A. Julbe, J. -C. Ruiz and B. Fournel: Journal of European Ceramic Society 30 (2010), p.1691.

DOI: 10.1016/j.jeurceramsoc.2010.01.021

[3] A. Hertz, S. Sarrade, C. Guizard and A. Julbe: Journal of European Ceramic Society 26 (2006, ), p.1195.

DOI: 10.1016/j.jeurceramsoc.2004.12.033

[4] C. Guizard, A. Julbe, S. Sarrade, O. Robbe and S. Papet: Chemical reaction of metal-organic precursors in supercritical CO2. Application to ceramic oxides preparation, in: Proceeding of 8th Meeting on Supercritical fluids, Bordeaux, France (2002).

[5] S. Sarrade, L. Schrive, C. Guizard and A. Julbe: Manufacture of single or mixed metal oxides or silicon oxide, Patent WO9851613 (1998).