Preparation of Hierarchical Porous Silicon Carbide Monoliths via Ambient Pressure Drying Sol-Gel Process Followed by High-Temperature Pyrolysis

Hierarchical porous silicon carbide (SiC) attracts great attention due to its superior chemical resistance, high thermal shock resistance, and excellent thermal stability. The preparation of a porous SiC monolith via a simple sol-gel method is limited by either the high cost of the raw materials or the special time-consuming drying process. Herein, we report an ambient drying sol-gel approach for the synthesis of organic-inorganic hybrid monolithic gels which can be converted into hierarchical porous SiC monoliths upon pyrolysis at 1400 degrees C. The as-synthesized SiC monoliths possess hierarchical pores with macropores of 4.5 mu m and mesopores of 2.0 nm. The porosities, specific surface areas and compressive strengths of the hierarchical porous SiC monoliths are 71.3%, 171.5 m(2)/g and 7.0 +/- 0.8 MPa, respectively.