Langmuir, Vol.22, No.7, 3068-3072, 2006
Ultralow temperature synthesis of ordered hexagonal smaller supermicroporous silica using semifluorinated surfactants as template
Ordered hexagonal smaller supermicroporous silica (JLU-14(L) and JLU-11(L)) has been successfully synthesized at ultralow temperature (0 similar to -20 degrees C) by semifluorinated surfactants, which is extensively investigated by X-ray diffraction, N-2 adsorption, and transmission electron microscopy. X-ray diffraction shows that the peak intensity of the samples increases with decreasing synthesis temperatures in the range of 0 similar to -20 degrees C, indicating that the ordering of porous silica improves with decreasing synthesis temperature. N-2 adsorption/desorption isotherms show that JLU-14L has both ordered smaller hexagonal supermicropores (1.27 and 1.28 nm) and disordered micropores (0.67 nm). Such hierarchically porous materials with micro/supermicroporosity should be potentially important for fast diffusion of reactants and products in catalytic reactions. The ultralow temperature synthesis is a crucial factor for the formation of ordered smaller supermicropores and the control of microporosity in JLU-14(L).
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