Solventless Acid‐Free Synthesis of Mesostructured Titania: Nanovessels for Metal Complexes and Metal Nanoclusters

Abstract

A new and highly reproducible method to obtain mesostructured titania materials is introduced in this contribution. The mesostructured titania is obtained by employing self‐assembled structures of non‐ionic alkyl‐poly(ethylene oxide) surfactants as templates. The materials are produced without additional solvents such as alcohols, or even water. Only the titanium(IV) ethoxide and the surfactant (C12EO10) are needed. Water, in the form of that attached to the surfactant and from the atmosphere, induces growth of titania nanoclusters in the synthesis sol. It is indicated that these nanoclusters interact with the surfactant EO‐head groups to form a new titanotropic amphiphile. The new amphiphiles self‐assemble into titanium nanocluster–surfactant hybrid lyotropic phases, which are transformed to the final mesostructured materials by further condensation of the titania network. The titania materials can be obtained also with noble‐metal particles immobilized in the mesostructured framework. It is seen that when different metal salts are used as the metal precursors, different interactions with the titania walls are found. The materials are characterized by X‐ray diffraction (XRD), polarization optical microscopy (POM), transmission electron microscopy (TEM), UV‐vis spectroscopy, and micro‐Raman analysis.

Cu/ZnO aggregates in siliceous mesoporous matrices: Development of a new model methanol synthesis catalyst

“…By embedding the catalytically active component into a well-defined superstructure (e.g., a hierarchically structured mesoporous matrix), it should be possible to simultaneously simplify and miniaturize the supported catalyst [14][15][16][17][18][19][20] and to utilize in the preparation the favorable effects of the spatially confined reaction conditions on the chemistry occurring in the porous solid [21]. However, this approach carries the risk of interference by the pore walls of the matrix.…”

Nano-sized blue spectral shift in sol–gel derived mesoporous titania films

“…Their studies have shown that appeared nanoclusteres during process of controlled Ti(OEt) 4 effectively interact with surfactant CH 3 (CH 2 ) n (OCH 2 CH 2 ) m OH which favors formation of nanoclaster/non-ionic surfactant ''titanotropic'' mesophase that undergoes hydrolytic polycondensation to give mesostructured titania with a wormhole structure, an amorphous titania framework, and uniform pore size distribution. The surfactant pre-organizes the clusters, which are attached to its head group [26]. We assume that for the case of use the Triton X-100 the similar reaction should be observed.…”

“…[25]. Dag and co-workers have fabricated mesoporous TiO 2 using Ti(OEt) 4 as precursor and non-ionic surfactant CH 3 (CH 2 ) n (OCH 2 CH 2 ) m OH [26], which is similar to Triton X-100. Their studies have shown that appeared nanoclusteres during process of controlled Ti(OEt) 4 effectively interact with surfactant CH 3 (CH 2 ) n (OCH 2 CH 2 ) m OH which favors formation of nanoclaster/non-ionic surfactant ''titanotropic'' mesophase that undergoes hydrolytic polycondensation to give mesostructured titania with a wormhole structure, an amorphous titania framework, and uniform pore size distribution.…”

The effect of anions of transition metal salts on the structure of modified mesostructured silica films and monoliths

“…Gö ltner and co-workers [11] showed that nonionic amphiphilic diblock copolymers with a polyethylene oxide head group and a polystyrene tail group could also be used as a template to create crack-free mesoporous silica monoliths. Note also that the C n EO m type surfactants have been successfully applied to prepare mesoporous transition metal oxides that are not accessible using the electrostatic templating method [12][13][14]. The metal alkoxides that readily hydrolyze to the corresponding metal oxide can also be templated using C n EO m type non-ionic surfactants [12,13].…”

“…Note also that the C n EO m type surfactants have been successfully applied to prepare mesoporous transition metal oxides that are not accessible using the electrostatic templating method [12][13][14]. The metal alkoxides that readily hydrolyze to the corresponding metal oxide can also be templated using C n EO m type non-ionic surfactants [12,13].…”