Highly crystalline silicon carbide of controlled mesoporosity

The control of porosity in silicon carbide (SiC) at the mesoporous scale is a major concern for a range of separation applications. It was recently reported that mesoporous amorphous SiC could be synthesized by templating polycarbosilane precursors around polymeric templates, and after pyrolysis at 1000 degrees C under inert atmosphere. In this publication, we report the synthesis of highly crystalline mesoporous beta-SiC based on the same approach, but involving much higher temperature pyrolyses (up to 1900 degrees C). The structure evolution with regards to the pyrolysis temperature is carefully studied by means of various analytical tools. Finally, the influence of different synthesis parameters on the control of the mesopomus structure is also discussed. It is shown for the first time that pure mesoporous beta-SiC with 10 nm pore diameter and a specific surface area larger than 50 m(2)/g can be obtained with a very high degree of crystallinity.