Porous biomorphic silicon carbide nanofibers from bacterial nanocellulose

Abstract

This paper reports the synthesis of biomorphic SiC from bacterial nanocellulose (BNC) aerogel templates through silicon vapor infiltration-reaction. The as-received bacterial nanocellulose hydrogels were submitted to CO2 supercritical drying to form BNC aerogels that were pyrolyzed at 800 °C. The carbon aerogels were placed on top of a silicon powder bed and heated to 1300 °C for Si-vapor infiltration-reaction. XRD phase analysis confirmed that biomorphic β-SiC nanofibers resulted from Si reaction with carbon. Morphological characterization by scanning electron microscopy revealed that the formed SiC maintained the original nanofibrous structure of BNC. Residual carbon was observed in the thermogravimetric analysis. The specific surface area decreased after vapor infiltration, although the porosity remained above 90%. The resulting electrical resistivity of 3.7 Ω cm for highly porous β-SiC is above other studies on SiC with similar structure.