A new approach for mesoporous carbon organofunctionalization with maleic anhydride

Abstract

Mesoporous carbon replicas CMK-3 and CMK-n were organofunctionalized with maleic anhydride by a new and simple methodology. These materials have been characterized by nuclear magnetic resonance (NMR), infrared (IR), Raman and X-ray photoelectron (XPS) spectroscopies, thermogravimetry, small-angle X-ray diffraction, nitrogen sorption and transmission electron microscopy (TEM). The attachment of maleic anhydride was confirmed by 13C NMR, which showed a peak at 168ppm, assigned to the carbonyl of maleic anhydride, as well as by the new band at 1728cm−1 attributed by IR to carbonyl groups. Increased amounts of this group were also demonstrated by C1s and O1s XPS spectra. The surface area, pore volume and pore size decreased after organofunctionalization. Small-angle X-ray diffractometry, nitrogen sorption and TEM data confirm that mesostructures of carbons were maintained even after organofunctionalization, in which the set of CMK-3 and CMK-n carbons have a 2D-hexagonal structure and domains of 3D-cubic, respectively. An interesting feature from Raman spectroscopy is the degree of graphitic order for mesoporous carbons that increased after reaction with maleic anhydride, where the D and G intensity ratios decreased from 2.6 to 1.9 for CMK-3 and from 2.3 to 2.0 for the CMK-n carbons.