Bottom up anatase monodisperse nanoparticles grown on sepiolite showing high thermal stability and optimal optical properties for self-cleaning applications

Powder samples of anatase monodisperse nanoparticles (np's) have been in-situ synthesized from sepiolite microparticles doped with TiIV. The role of this clay is double, by one hand, it acts as a chemical reactor, and on the other hand, it becomes a solid substrate for particles, which pin them up avoiding Ostwald ripening process on heating. In this work we show the high thermal stability of these metastable anatase particles up to 850 degrees C, around 200 degrees C above the anatase/rutile transformation for ordinary powder particles. Relevant information about the electron bandstructure has been obtained both, by optical diffuse reflectance and emission spectroscopy, which revealed the nature of photon absorption and recombination around the band-gap which determine the utility of this materials as a self-cleaning agent for solid materials.

Automated summary

In this study, powder samples of monodisperse anatase nanoparticles were synthesized in-situ from sepiolite microparticles doped with TiIV. The sepiolite clay acted as a chemical reactor and a solid substrate for the particles, preventing their growth during heating. The high thermal stability of these metastable anatase particles was demonstrated, with a transformation temperature 200 degrees C above that of ordinary powder particles. The electron bandstructure and photon absorption and recombination properties were also investigated, providing insights into the potential use of these materials as self-cleaning agents for solid materials.