Improvement of the hydrothermal stability of fluorinated MCM-41 material

Abstract

The formation of regular hexagonal MCM-41 framework was studied using cetyltrimethyl ammonium bromide (CTMABr) as the surfactant template and aerosil-200 powder silica as the silica source under static condition in the presence of fluoride or chloride anions. The hydrothermal stability of MCM-41 framework synthesized in the presence of fluoride anions was found to be remarkably improved as compared with those synthesized in the presence of chloride anions. The improvement of the hydrothermal stability of MCM-41 material is most likely attributed to the formation of Si-F bonds on the surface of the mesopores of MCM-41, leading to the natural resistance of the fluorinated surface to the hydrolysis by water molecules.