Synthesis of manganese oxide microparticles using supercritical water

• Manganese oxides of different oxidation states were synthesized in SCW.
• MnCO3 was formed when glycerol was used with SCW.
• Calcination step was added to obtain various phases of manganese oxides.
• MnO2, MnCO3, Mn2O3, and MnO + Mn3O4 were successfully synthesized.

Manganese compounds of different oxidation states such as MnO2, MnCO3 Mn2O3, and a mixture of MnO + Mn3O4 were synthesized using supercritical water (SCW) and calcination process. The X-ray Diffraction (XRD) patterns confirmed that the use of glycerol as a reducing agent in SCW process was successful in preventing oxidation of manganese products. Scanning electron microscopy (SEM) images of the manganese products showed micro-sized particles with different morphology depending on the product. The simple two step synthesis procedure described in this paper allows easy control of manganese oxidation states with direct applicability in large scale production on an industrial level.

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