Highly dispersed and non-agglomerated α-MnO2 nano-needles of dimensions 20-30 nm have been synthesized by the application of ultrasound radiation on the aqueous solution consisting of manganese(3)acetate close to neutral pH followed by mild drying. With a similar reaction system, hot hydrolysis (non-sonochemical process) produced β-MnO2 nano-rods of length 100-200 nm but with high degree agglomeration. Sonochemical cavitation phenomenon is suggested to have a pronounced effect for the formation of special phase and morphology. The effect is proved by the difference in the intermediate products which has difference in crystalinity and phase-purity. The intermediate phases are identified to be single-phase γ-MnOOH for the non-sonochemical reaction and mixture of γ-MnOOH, α-MnO2 and β-MnO2 for the sonochemical products.
Bibliographical noteFunding Information:
This work was supported by the ERC program of MOST/KOSEF (Grant No. R11-2002-102-00000-0) and the Ministry of Commerce, Industry, and Energy of Republic of Korea (M10428060003-04L2806-00310). Dr. V. Ganesh Kumar would like to thank KOFST, Seoul, KOREA for offering a Brain Pool Visiting Fellowship.
All Science Journal Classification (ASJC) codes
- Chemical Engineering (miscellaneous)
- Environmental Chemistry
- Radiology Nuclear Medicine and imaging
- Acoustics and Ultrasonics
- Organic Chemistry
- Inorganic Chemistry