Catalytic Decomposition of H(2)O(2) in the Aqueous Dispersions of the Potassium Polytitanates Produced in Different Conditions of Molten Salt Synthesis

It is shown that the potassium polytitanate powder (PPT) synthesized at 500 °C via the treatment of powdered TiO(2) (rutile) in molten mixtures of KOH and KNO(3) is a cheap and effective catalyst of H(2)O(2) chemical decomposition in aqueous solutions. At the same time, the PPT catalytic activity strongly depends on the [TiO(2)]:[KOH]:[KNO(3)] weight ratio in the mixture used for the synthesis, increasing with [KNO(3)] in the order of PPT (30:30:40) < PPT (30:50:20) < PPT (30:70:0). The obtained results are explained by increased [Ti(3+)] in the PPT structure (XPS data), which is grown in this order from 0 to 4.0 and 21.9 at.%, respectively, due to the reduced oxidation activity of the melt used for PPT synthesis. The mechanism of the autocatalytic process taking place in the PPT-H(2)O(2)-H(2)O system is analyzed. Taking into account the data of FT-IR spectroscopy, it is assumed that the increased catalytic activity of the investigated materials is related to the increased surface concentration of the Ti(4+)-O(H)-Ti(4+) groups, formed from the Ti(3+)-O(H(3)O(+))-Ti(4+) clusters and further transformed into Ti-O-O-H catalytic centers. Some possible applications of the PPT-H(2)O(2)-H(2)O catalytic system, including the oxidation processes of green chemistry and photo-catalysis, are discussed.