A new family of mesoporous silica molecular sieves with micelle-templated structures (MTS) has been synthesized using nonionic ethoxylated sorbitan esters, namely, Tween-20, -40, -60, or -80, as structure-directing agents. These MTS materials possess a wormhole-like framework typical of MSU-X mesostructures, with intraparticle (framework) pore sizes in the 3.0−4.0 nm range. Unlike previously reported MSU-X silicas, these new derivatives form monodispersed small particles in the 30−60 nm range, depending on the nature of the surfactant, and exhibit substantial interparticle (textural) porosity in the 9−20 nm range. The sorbitan surfactants are nontoxic, biodegradable, and biocompatible when solvent free, making them attractive structure directors for the synthesis of mesoporous materials. The combination of complementary framework and textural pore distributions should be advantageous in the use of the mesostructures as heterogeneous catalysts, particularly for reactions that are normally diffusion limited.

Here we report the synthesis of a series of new nanocrystalline TiO2-(MoO3) core−shell materials whose photoabsorption energy (PE, the energy required to excite TiO2-core valence band electrons to MoO3-shell conduction band states) properties are correlated with both the nanoparticle size and the degree of chemical interaction between the TiO2 core and the MoO3 shell. The TiO2-(MoO3) nanoparticle size can be readily adjusted from 80 to 40 Å, and in this series, the PE decreases from 2.88 to 2.60 eV with decreasing particle size. The systematic PE red-shift exhibited by the core−shell materials is ascribed to the change in the relative position of the MoO3-shell conduction band as it evolves from less than a monolayer to a two monolayer shell.