Manganese Trioxide with Various Morphologies: Applications in Catalytic Dye Degradation

摘要

abstract_textpHierarchical manganese trioxides (Mn2O3) with different morphologies are prepared by thermal treatment of carbonate precursors synthesized using a facile and template-free hydro-solvothermal method. Various morphologies of Mn2O3 have evolved as a function of precursor salts keeping the solvent system and temperature of synthesis intact. On hydro-solvothermal treatment, manganese carbonate with different microstructures is formed first and on subsequent calcination at 500 degrees C, the carbonates are converted into manganese trioxide with the retention of the initial microstructure. While formation of Mn2O3 microcubes is achieved with MnCl2 and Mn(NO3)(2) as precursor salts, microspheres and microflakes are obtained with Mn(OAc)(2) and MnC2O4 precursors, respectively. The average microcrystal size varied from similar to 10-20 (+/- 5) mu m with somewhat high surface areas. The catalytic dye degradatin studies conducted on Mn2O3 microcubes and microspheres in aqueous acidic mediums show rapid removal of dyes in the dark. While an aqueous acidic solution of methyl orange (MO) is decolorized in 2 min, more than 90 of rhodamine B (RhB) and methylene blue (MB) are degraded within 50-60 min. Retention of catalytic activity after five cycles indicates their reusability and promise as simple binary oxide catalysts for wastewater treatment./p/abstract_text