Design and Preparation of Nanostructured Tio2 Materials by Using Supercritical Co2 Silanization, and Post-functionalization

The present work presents the latest advances for the modification of TiO2 surfaces by their functionalization with complex organic molecules through a scCO2 strategy. Two strategies were followed: the first strategy involved the deposition under anhydrous conditions onto the TiO2 surface of laboratory prepared silane containing nitro-phenyl and nitro-formyl groups, leading to the products designed as Ti-NP and Ti-FP. The second strategy involved the silanization of the commercial silane 3(trimethoxysilyl)propyl methacrylate (MPTMS) on the TiO2 surface, followed by the post functionalization with (1,2)-diaminocylohexane (Dac), using also scCO2 as solvent. As a result, grafted TiO2 nanoparticles designated as Ti-MP-Dac were obtained. Modified TiO2 nanopowders were characterised by thermogravimetric analysis, ATRIR spectroscopy, and UV–vis diffuse reflectance.