Facile Synthesis of Highly Porous Carbon from Rice Husk

Highly porous carbon materials have attracted great interest for a wide range of important applications. Many examples for their synthesis exist, but these synthetic processes can be quite complex and also very time-consuming. There is still a major challenge to develop a facile yet versatile conceptual approach to produce them. Here, we present an efficient, activation-free, post-treatment-free strategy for the synthesis of highly porous carbon by a simple carbonization of a mixture of rice husk and polytetrafluoroethylene (PTFE) powder. PTFE employed here can in situ generate HF to etch out natural silica during the carbonization treatment of rice husk. This strategy not only reduces the synthesis procedure by combining carbonization and post-removal of silica into a single step but also eliminates completely the usage of hazardous HF or corrosive NaOH or KOH. The as-synthesized carbon materials exhibit a BET surface area as high as 2051 m(2)/g without any activation treatment, which is about 20 times enhanced in porosity compared to that of the traditional carbon material from rice husk. With the combination of the high porosity and the valuable hierarchical porous structure, the as-prepared porous carbon materials serve well as electrodes for supercapacitive energy storage, including a large capacitance of 317 F/g, good rate performance, and high capacitances per surface area. These findings could provide a new avenue for the facile production of high-performance porous carbon materials with promising applications in various areas.