Improvement of the hydrothermal stability of fluorinated MCM-41 material

The formation of regular hexagonal MCM-41 framework was studied using cetyl trimethyl ammonium bromide (CTMABr) as the surfactant template and aerosil- 200 powder silica as the silica source under static condition in the presen ce of fluoride or chloride anions. The hydrothermal stability of MCM-41 fra mework synthesized in the presence of fluoride anions was found to be remar kably improved as compared with those synthesized in the presence of chlori de 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 fluorina ted surface to the hydrolysis by water molecules. (C) 2000 Elsevier Science B.V. All rights reserved.