A wide range of experimental data are reported for the first time on the TiO2 prepared by hydrolysis of highly concentrated Ti((OPr)-Pr-i)(4) in water solutions of quaternary ammonium compounds (QACs). These TiO2 materials have been shown to be photocatalytically active under visible light irradiation (LED, 450 nm) using acetone as a model substrate oxidized in the gas phase. Five-fold increase in activity in comparison with the commercial photocatalyst KRONOClean 7000 is achieved. Colloidal solutions of hydrolyzed Ti((OPr)-Pr-i)(4) have been studied by SAXS method suggesting the way in which QACs solutions may influence the final composition of TiO2. Phase composition, morphology, texture and surface properties of the modified TiO2 have been studied using XRD, BET, SEM and low-temperature FTIR with CO probe. The surface elemental composition has been investigated by XPS method. Additional low-energy levels and high concentration of acid surface sites originated from N/C-doping, are likely to be the main reasons for exceptional photocatalytic performance of these samples. [GRAPHICS] .