Porosity and nanostructure of silicon oxycarbide derived carbon

Abstract

The unique nanostructure of polymer derived pseudo-amorphous silicon oxycarbide ceramics, which comprises of SiO2 nanodomains, turbostratic graphite, and mixed bond tetrahedral of Si-O/C, enables processing of nanostructured materials with enhanced specific surface area and nanoporosity. Selective etching of the SiO2 nanodomains in a polysilsesquioxane derived SiOC structure left behind highly porous carbonaceous materials with specific surface area in excess of 800 m2g-1, where the obtained porosity and their distribution are remnant of the SiO2 nanodomains. High resolution transmission electron microscopy clearly identified the nanopores and graphene type layers in the oxycarbide derived carbons. The carbon in the SiOC ceramics was found to be better ordered after HF leaching process. Volume fraction of the micropores in the derived carbon was found to increase with the pyrolysis temperature of the parent silicon oxycarbide.

Keywords

• Polymer derived ceramics
• SiOC
• Nanoporosity
• Transmission electron microscopy
• Oxycarbide derived carbon