Structural, Morphological, and Catalytic Properties of Cryptomelane

Abstract

The cryptomelane samples were synthesized by potassium permanganate reduction: with manganese acetate (solid-phase reaction)—OMS-2(SSt) sample, with manganese sulfate (reflux method)—OMS-2(Ref) sample, with maleic acid (sol–gel method)—OMS-2(SG) sample, and also by KNO3 and MnSO4 melting together—OMS-2(MS) sample. All the samples thus obtained were characterized by XRD method, SEM, FT-IR spectroscopy, N2 adsorption, and also by pH-metry. The cryptomelane samples (0.5 g each) were tested as catalysts for the reaction of ozone decomposition at 20 °C, an initial ozone concentration in the ozone air mixture (OAM) of 100 mg/m3, and an OAM flow rate of 16.6 cm3/s. The activity of the cryptomelane samples obtained by different methods changes in this sequence OMS-2(MS) > OMS-2(SG) > OMS-2(Ref) > OMS-2(SSt).