Selective Synthesis of Manganese Dioxide Polymorphs by the Hydrothermal Treatment of Aqueous KMnO4 Solutions
А. А. Егорова, Т. М. Бушкова, I. V. Kolesnik, A. D. Yapryntsev, Sergey Yu. Kottsov, А. Е. Баранчиков
Abstract
Abstract The hydrothermal treatment of neutral and acidified KMnO4 solutions at concentration of 0.037–0.093 mol/L and temperature of 120, 170, and 220°С for 24 h leads to selective synthesis of three different manganese dioxide modifications: α-MnO2, δ-MnO2, and β-MnO2. The temperature of hydrothermal treatment and medium acidity has been shown to affect considerably the phase composition of KMnO4 reduction products and reaction yield. The obtained samples of MnO2 have been characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and diffuse reflectance spectroscopy.
Topics & Concepts
Hydrothermal circulationManganeseRaman spectroscopyScanning electron microscopeAqueous solutionChemistryDiffuse reflectance infrared fourier transformYield (engineering)Hydrothermal synthesisSpectroscopyPhase (matter)Nuclear chemistryInorganic chemistryAnalytical Chemistry (journal)Materials scienceChemical engineeringCatalysisPhotocatalysisPhysical chemistryOrganic chemistryMetallurgyOpticsEngineeringComposite materialPhysicsQuantum mechanicsCatalytic Processes in Materials ScienceSupercapacitor Materials and FabricationGeochemistry and Elemental Analysis