A group of selected hexafluorometallates ([AlF 6 ] 3− , [TiF 6 ] 2− , [ZrF 6 ] 2− , and [SiF 6 ] 2− ) has been adsorbed at the surface of titanium dioxide. Such modification influenced the electronic and chemical properties of TiO 2 , as well as its photoactivity. The modification with [TiF 6 ] 2− inhibited the efficiency of OH • production but enhanced the generation of photocurrent and singlet oxygen. The results of modifications with [ZrF 6 ] 2− were the oppositegeneration of 1 O 2 was not observed in this case and photocurrents were lower; however, due to a better OH • production, degradation of herbicides was faster.