High-temperature treated TiO2 modified with 3-aminopropyltriethoxysilane as photoactive nanomaterials

A series of titanium dioxide (TiO2) modified with 3-aminopropyltriethoxysilane (APTES) was prepared by high-temperature calcination in an argon atmosphere in the temperature range from 800 to 1,000 degrees C. The properties of the obtained samples were compared with those of pure TiO2 annealed under the same conditions. Examining electron paramagnetic resonance (EPR) parameters at room temperature for APTES-TiO2 showed an intense resonance line from defects related to conducting electrons with g (eff) from 2.0028 to 2.0026 and 1.9052 for temperatures 800, 900, and 1,000 degrees C, respectively, while for pure calcined TiO2, these ERP lines were not observed. With the increase in the calcination temperature to 900 degrees C for APTES-TiO2 samples, the EPR increases linearly. This has been combined with a relatively high anatase content and small crystallites. The EPR line intensity at RT calculated for 1 g of sample showed an almost linear relationship with the photoactivity in removing ORANGE II dyes from water.