Synthesis and Characterization of Bifunctionalized Ordered Mesoporous Materials

摘要

Direct synthesis (co-condensation reaction) and post-synthesis reaction (grafting) are combined for the first time to efficiently fabricate bifunctionalized ordered mesoporous materials (OMMs). Ethylenediamine-containing OMMs (ED-MCM-41) were first synthesized via direct synthesis and then further modified by the phenyl (PH) group in a supercritical fluid (SCF) medium via grafting reaction, resulting in OMMs with ED and PH groups (PH-ED-MCM-41). X-ray diffraction (XRD) patterns, N_2 sorption properties, transmission electron microscopy (TEM), ~(29)Si and ~(13)C magic angle spinning (MAS) NMR, chemical analysis, and hydrothermal treatment were used to characterize the bifunctionalized materials. Experiments show that bifunctionalized OMMs can be efficiently prepared by modifying the directly synthesized monofunctionalized OMMs via grafting reaction in a supercritical fluid medium. Both functional groups are distributed uniformly at the surfaces. The advantage of bifunctionalized OMMs over monofunctionalized OMMs was illustrated by introducing thiol groups into ED-MCM-41 materials and the subsequent formation of CdS nanocrystals inside thiol- and ED-functionalized MCM-41 (HS-ED-MC-41). Because of the variety of the functional groups that can be introduced into OMMs by direct synthesis or post-synthesis reaction, it is expected that the present strategy could provide a generally applicable approach to the design of OMMs with two functional groups.