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 °C, around 200 °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. © 2023 The Authors

The Authors acknowledge the financial support of PID2020-119130GB-I00 project funded by the Spanish Ministerio de Ciencia e Innovación (MCIN) and Agencia Estatal de Investigación (AEI), MCIN/AEI /10.13039/501100011033. We also thank to the Unit of Characterization of Materials of ICMM (IR and Ellipsometry, x-ray Diffraction and Thermal analysis services) as well as the “Centro Nacional de Microscopía Avanzada-CNME” for the HRTEM pictures.

Supplementary data

Peer reviewed