Photocatalytic Activity of TiO₂ Modified with Hexafluorometallates—Fine Tuning of Redox Properties by Redox-Innocent Anions

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 opposite—generation 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.