Facile Synthesis of Ordered Microporous Carbons Using Zeolite Template

Abstract

Synthesis of ordered microporous carbon of various structures employs zeolite-templating methods. In order to liberate carbon from zeolite/carbon composite, the zeolite template is removed using HF in most cases. In the present work, concerning severe toxicity of HF, we report that beta and X zeolite templates can readily be removed using NaOH and HCl instead of HF. The resultant carbons have high argon adsorption capacity, thermal stability, and electrical conductivity comparable to those of conventional HF-treated carbons. The NaOH-treated carbons have increased oxygen content, and the oxygen-containing functional groups may be useful for further research on organic functionalization. On the other hand, the oxygen groups can be reduced by hydrogen to increase the conductivity, similar to the case of reduction of graphene oxide to reduced graphene oxide. The subsequently reduced carbon exhibits a notably improved performance as a nonaqueous electrical double-layer capacitor. By introducing the HF-free removal of zeolite template, large-scale synthesis of ordered microporous carbon is possible with safety toward practical applications.