Cryptomelane modified with transition metal ions in the reaction of ozone decomposition

Abstract

Original samples of cryptomelane OMS-2 were synthesized by the reflux method using the KMnO₄ reduction reaction with MnSO₄. Based on them, cryptomelane samples doped with transition metals were obtained by impregnation – M/OMS-2 (M = Cu²⁺, Co²⁺, Fe³⁺). All the samples thus obtained were characterized by XRD, SEM, and FT-IR spectroscopy methods. It is shown that all samples are homogeneous – they contain only the cryptomelane phase. Doped metal ions do not form oxide phases. The samples were tested in the ozone decomposition reaction at its concentration of 100 mg/m³. It was found that the effect of metal ions in the ozone decomposition reaction is determined by their nature and content. For low-percentage samples of M/OMS-2 (ω_М = 0.64 wt.%), сopper(II) and iron(III) ions with respect to OMS-2 have an accelerating effect, while cobalt(II) ions have an inhibitory effect. For high-percentage samples of M/OMS-2 (ω_М = 9.66 wt.%), сopper(II) ions inhibit ozone decomposition, while cobalt (II) and iron(III) ions accelerate ozone decomposition.

Keywords:

• Cryptomelane
• transition metal ions
• ozone

Authors′ contributions

TR analyzed X-ray diffraction and SEM patterns, developed a methodology for analyzing kinetic data and generalized the results obtained. AT developed a technique for cryptomelane samples preparation and took diffractometer readings. ZS and IS studied the kinetics of ozone decomposition and made necessary calculations.

Author details

TR, professor, worked as a Head of the Department of Inorganic Chemistry and Chemical Ecology of Odessa I.I. Mechnikov National University. Her research interests are nanochemistry, nanotechnology, coordination chemistry and catalysis of redox reactions. AT worked as a docent of the Department of Inorganic Chemistry and Chemical Ecology of Odessa I.I. Mechnikov National University. Her research interests are nanochemistry, coordination chemistry and catalysis of the ozone decomposition reaction. ZS and IS are the students at the Faculty of Chemistry and Pharmacy of Odessa I.I. Mechnikov National University. Their research interests are environmental catalysis.

Additional information

Funding

T

he study was carried out with the support of the Ministry of Education and Science of Ukraine.