Mesoporous nonsiliceous materials

Meanwhile, SDA-mediated syntheses have also been used successfully in the preparation of nonsilica mesoporous metal oxides,54-60 metal sulfides,61 and metal phosphates.62,63 An account devoted to nonsiliceous mesoporous materials and the host-guest chemistry of such systems can be found in a review by Zhao and coworkers.64... 

Oxides Compared to silica-based networks, nonsiliceous ordered meso-poious materials have attracted less attention, due to the relative difficulty of applying the same synthesis principles to non-sihcate species and their lower stability (227). Nonsiliceous framework compositions are more susceptible to redox reactions, hydrolysis, or phase transformations to the thermodynamically preferred denser crystalline phases. Template removal has been a major issue and calcination often resulted in the collapse of the mesostracture. This was the case for mesostractured surfactant composites of mngsten oxide, molybdenum oxide, and antimony oxide, and meso-structured materials based on vanadia that were obtained at early stages. Because of their poor thermal stability, none of these mesostructures were obtained as template-free mesoporous solids (85, 228, 229). 

Compared to sihca-based networks, nonsiliceous ordered mesoporous materials have attracted less attention, due to the relative difficulty to apply the principles employed to create mesoporous silica to nonsilica compositions. Other framework compositions are much more sensitive than silica to redox reactions, hydrolysis, or phase transformations. The reactivity of the inorganic precursors is much more difficult to control in the case of transition metal oxides, the reaction kinetics being much faster. Also, crystalline nonsiliceous frameworks are less prone to adapt the curvature of micellar aggregates, whereas the amorphous nature of silica allows for certain flexibility. 

Nonsiliceous Mesoporous Materials via Mediated Coloumbic Interaction (I X S )... 

This elegant methodology can be exploited to synthesize other nonsiliceous mesoporous materials. In fact. Yada et al. observed several similar transformations of lamellar yttrium-based mesophases teinplated by dodecyl sulfate to the corresponding hexagonal phases. In this case, no cubic inesophases were observed, even after long... 

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