Improved Photocatalytic Activity of Polysiloxane TiO2 Composites by Thermally Induced Nanoparticle Bulk Clustering and Dye Adsorption

Fine control of nanoparticle clustering within polymeric matrices can be tuned to enhance the physicochemical properties of the resulting composites, which are governed by the interplay of nanoparticle surface segregation and bulk clustering. To this aim, out-of-equilibrium strategies can be leveraged to program the multiscale organization of such systems. Here, we present experimental results indicating that bulk assembly of highly photoactive clusters of titanium dioxide nanoparticles within an in situ synthesized polysiloxane matrix can be thermally tuned. Remarkably, the controlled nanoparticle clustering results in improved degradation photocatalytic performances of the material under 1 sun toward methylene blue. The resulting coatings, in particular the 35 wt % TiO2-loaded composites, show a photocatalytic degradation of about 80%, which was comparable to the equivalent amount of bare TiO2 and two-fold higher with respect to the corresponding composites not subjected to thermal treatment. These findings highlight the role of thermally induced bulk clustering in enhancing photoactive nanoparticle/polymer composite properties.

Mechanical Grinding Preparation and Characterization of TiO₂-Coated Wollastonite Composite Pigments

TiO₂-coated wollastonite composite pigments were prepared by the mechano-chemical grinding of wollastonite and TiO₂ powder together in a wet ultrafine stirred mill. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and infrared spectra were used to investigate the microstructures and morphologies of the composite and the reaction mechanism. The results indicate that the TiO₂-coated wollastonite composite pigments have similar properties to titanium dioxide pigment, showing much better properties than dry and wet mixing of wollastonite and TiO₂. The hiding power of TiO₂-coated wollastonite composite pigments (45% TiO₂) is 17.97 g/m², reaching 81.08% of titanium dioxide. A firm combination between wollastonite and TiO₂ is obtained through a surface dehydroxylation reaction during the mechano-chemical method.

Si doped highly crystalline mesoporous In2O3 nanowires: synthesis, characterization and ultra-high response to NOx at room temperature

The synthesized INW-2 has an ultrathin surface layer and high density defects. The special structure offers available active centers for gas/surface reactions. INW-2 sensor possesses the ultrahigh response and selectivity to NOx at room temperature.