Molecules (Basel, Switzerland), 2023-06, Vol.28 (13)
2023
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- Autor(en) / Beteiligte
- Titel
- Catalytic Decomposition of H[sub.2]O[sub.2] in the Aqueous Dispersions of the Potassium Polytitanates Produced in Different Conditions of Molten Salt Synthesis
- Ist Teil von
- Molecules (Basel, Switzerland), 2023-06, Vol.28 (13)
- Ort / Verlag
- MDPI AG
- Erscheinungsjahr
- 2023
- Quelle
- Free E-Journal (出版社公開部分のみ）
- Beschreibungen/Notizen
- It is shown that the potassium polytitanate powder (PPT) synthesized at 500 °C via the treatment of powdered TiO[sub.2] (rutile) in molten mixtures of KOH and KNO[sub.3] is a cheap and effective catalyst of H[sub.2]O[sub.2] chemical decomposition in aqueous solutions. At the same time, the PPT catalytic activity strongly depends on the [TiO[sub.2]]:[KOH]:[KNO[sub.3]] weight ratio in the mixture used for the synthesis, increasing with [KNO[sub.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[sup.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[sub.2]O[sub.2]-H[sub.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[sup.4+]-O(H)-Ti[sup.4+] groups, formed from the Ti[sup.3+]-O(H[sub.3]O[sup.+])-Ti[sup.4+] clusters and further transformed into Ti-O-O-H catalytic centers. Some possible applications of the PPT-H[sub.2]O[sub.2]-H[sub.2]O catalytic system, including the oxidation processes of green chemistry and photo-catalysis, are discussed.