XPS investigation on nano-TiO2 modified by titanate coupling agent

Nano-TiO2 was modified with a titanate coupling agent, LICA38 [neopentyl (dially) oxy, tri (-dioctyl) pyrophosphate titanate]. X-ray photoelectron spectroscopy (XPS) was used to evaluate the surface characteristics of the bare and the modified nano-TiO2. It was demonstrated that the carbon content of the bare TiO2 is 37.9 atm. %, and that of the modified TiO2 is 47.2 atm. %. Moreover, the density of the -C-H (-C-C) and -C-O groups increases due to modification, and the atomic percentage of C=O and -OH groups reduces. These results indicate that the -C-H (-C-C) and -C-O groups from LICA38 have been introduced to the surface of nano-TiO2 by coupling reaction with the hydroxyl groups.