Influence of manganese oxides on the optical absorption and photocatalytic activities of titanium dioxide

Nanocrystalline titanium-manganese mixed oxides (TMMO) with Mn content of 13-16 at. % were first synthesized by manganese hydroxide precipitation on anatase or rutile particles. UV-vis absorption spectra were investigated in 2.4-6.0 eV region and revealed that compared with pure TiO 2 the presence of manganese oxides results in an increase of the absorption intensity and significant red shift of the TMMO absorption edge. Photocatalytic activity of pure TiO 2 , Mn 2+ doped TiO 2 and TMMO during the photocatalytic decomposition of the safranine dye under UV irradiation was studied. A great improvement of photocatalytic activity is registered for Mn 2+ -doped TiO 2 (anatase and rutile), and rutile-based TMMO sample.