Effect of the Method of Synthesis on the Photocatalytic and Sorption Properties for Potassium Polytitanates Doped with Di- and Trivalent Metal Ions

The paper describes the results of a physicochemical study of materials obtained in the K2O–MO(M2O3)–TiO2 systems (M = Ni, Mg, Al, Fe, Cr) by pyrolysis of citrate–nitrate compositions and by co-precipitation followed by hydrothermal treatment. It was shown that the nanoparticles formed in the hydrothermal process have a high sorption capacity towards the model dye (methylene blue), but do not show a noticeable photocatalytic activity. The use of the citrate–nitrate method for the synthesis of nanopowders provides materials with a markedly lower sorption capacity, but with a higher photocatalytic activity. Spectral studies were performed to estimate the band gap width of the synthesized samples. As a result, the optimal compositions for obtaining sorbents and photocatalysts in these systems were identified.