title: Shape-controlled synthesis of manganese oxide octahedral molecular sieve three-dimensional nanostructures.
abstract: Cryptomelane-type manganese oxide octahedral molecular (OMS) sieve three-dimensional (3D) nanostructures were synthesized via facile temple-free low-temperature hydrothermal reactions. Morphologies of the cryptomelane-type OMS-2 nanoparticles with tunnel dimension of 4.6 x 4.6 A can be tuned by varying reaction temperatures. At low temperature (120 degrees C), OMS-2 dendritic nanoclusters composed of uniform single-crystal nanotetragonal prisms with square cross-sections were formed. At high temperature (180 degrees C), the morphologies of OMS-2 became spherical dandelion-like microspheres composed of uniform single-crystal OMS-2 nanoneedles. Slow oxidation of Mn(2+) by Cr(2)O(7)(-) under hydrothermal conditions is critical for the formation of the hierarchically ordered OMS-2 3D nanostructures.
authors.affiliation: Department of Chemistry, Institute of Materials Science, University of Connecticut, Unit 3060, 55 North Eagleville Road, Storrs, CT 06269-3060, USA.
authors.forename: Jikang
authors.initials: J
authors.lastname: Yuan
authors.forename: Wei-Na
authors.initials: WN
authors.lastname: Li
authors.forename: Sinue
authors.initials: S
authors.lastname: Gomez
authors.forename: Steven L
authors.initials: SL
authors.lastname: Suib
mesh_terms: D017895:Manganese Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D010087:Oxides / Q000138:chemical synthesis* / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties
chemical_list: D017895:Manganese Compounds; D010087:Oxides; C027424:manganese oxide