Influences of modification of titanium dioxide by silane coupling agents on the photocatalytic activity and stability

In this paper, titanium dioxide modification with 3-aminopropyltriethoxysilane as a silicon source is presented. The TiO2/APTES photocatalysts were obtained utilizing a solvothermal method. Different concentrations of APTES dissolved in ethanol were used for materials preparation (10−3000 mM). The samples were characterized by different analytical methods such as FT-IR/DRS, UV–vis/DRS, XRD, SEM. The carbon and nitrogen content to confirm, as well as the BET specific surface area, were also measured. The analysis confirmed the presence of silicon, carbon and nitrogen in the TiO2 structure, suggesting that modification was carried out successfully. The carbon and nitrogen were also indications in the sample after the reusability test in water. The photocatalytic activity of the nanomaterials was investigated on the basis of methylene blue decomposition under UV light irradiation. Photocatalytic activity increases with the increase of APTES concentration used for modification. The novelty of research was to check the possibility of photocatalysts reuse. In this case, the sample with the highest decomposition degree was subjected to the reusability test. It it was found that the samples after this type of modification are not stable due to destruction of the APTES alkyl chains and detachment the amine groups during UV irradiation.