Abstract
Highly ordered hexagonal mesoporous silica materials (JLU‐20) with uniform pore sizes have been successfully synthesized at high temperature (150–220 °C) by using fluorocarbon–hydrocarbon surfactant mixtures. The fluorocarbon–hydrocarbon surfactant mixtures combine the advantages of both stable fluorocarbon surfactants and ordered hydrocarbon surfactants, giving ordered and stable mixed micelles at high temperature (150–220 °C). Mesoporous JLU‐20 shows extraordinary stability towards hydrothermal treatment (100 % steam at 800 °C for 2 h or boiling water for 80 h), thermal treatment (calcination at 1000 °C for 4 h), and toward mechanical treatment (compressed at 740 MPa). Transmission electron microscopy images of JLU‐20 show well‐ordered hexagonal arrays of mesopores with one‐dimensional (1D) channels and further confirm that JLU‐20 has a two‐dimensional (2D) hexagonal (P6 mm) mesostructure. ^29^Si HR MAS NMR spectra of as‐synthesized JLU‐20 shows that JLU‐20 is primarily made up of fully condensed Q^4^ silica units (δ=−112 ppm) with a small contribution from incompletely cross‐linked Q^3^ (δ=−102 ppm) as deduced from the very high Q^4^/Q^3^ ratio of 6.5, indicating that the mesoporous walls of JLU‐20 are fully condensed. Such unique structural features should be directly attributed to the high‐temperature synthesis, which is responsible for the observed high thermal, hydrothermal, and mechanical stability of the mesoporous silica materials with well‐ordered hexagonal symmetry. Furthermore, the concept of “high‐temperature synthesis” is successfully extended to the preparation of three‐dimensional (3D) cubic mesoporous silica materials by the assistance of a fluorocarbon surfactant as a co‐template. The obtained material, designated JLU‐21, has a well‐ordered cubic Im__3__m mesostructure with fully condensed pore walls and shows unusually high hydrothermal stability, as compared with conventional cubic mesoporous silica materials such as SBA‐16.