Synthesis of mesoporous carbons using silica templates impregnated with mineral acids

Abstract

The pore walls of SBA-15, SBA-16 and KIT-6 mesoporous silica were acidified via the impregnation of phosphoric acid or sulfuric acid prior to their use as a template for mesoporous carbon synthesis with furfuryl alcohol. The effect of acid functionalization on carbon synthesis was investigated using X-ray powder diffraction, N-2 adsorption, transmission electron microscopy, and solid-state C-13 and P-31 NMR spectroscopy. The results indicated that a significant portion of the impregnated mineral acid formed an ester with the surface silanol group. Therefore, the impregnated acid could lead to the selective formation of carbon frameworks inside the template pores, preventing external carbon deposition even when furfuryl alcohol was used excessively. The mineral acid impregnation yielded highly faithful carbon replicas of the mesoporous silica.