Physico-chemical characterization of nitrided mesoporous silicon MCM-41

Mesoporous nitrided MCM-41 was synthesized and physically characterized. The nitrogen species are predominantly present as imido NH groups as shown by infrared spectroscopy. The NH groups are located in the framework and are therefore inaccessible for reactant and probe molecules. Deuterium exchange experiments support this interpretation. The surface exposes Si–OH groups which are identical to silanol groups on pure silica; basic sites could not be detected by neither deutero-chloroform nor methylacetylene. We infer that a small number of NH2 groups are located at the surface of the pore walls which may be responsible for the activity for base-catalyzed reactions.