Well shaped Mn₃O₄ nano-octahedra with anomalous magnetic behavior and enhanced photodecomposition properties.
Very uniform and well shaped Mn₃O₄ nano-octahedra are synthesized using a simple hydrothermal method under the help of polyethylene glycol (PEG200) as a reductant and shape-directing agent. The nano-octahedra formation mechanism is monitored. The shape and crystal orientation of the nanoparticles is reconstructed by scanning electron microscopy and electron tomography, which reveals that the nano-octahedra only selectively expose {101} facets at the external surfaces. The magnetic testing demonstrates that the Mn₃O₄ nano-octahedra exhibit anomalous magnetic properties: the Mn₃O₄ nano-octahedra around 150 nm show a similar Curie temperature and blocking temperature to Mn₃O₄ nanoparticles with 10 nm size because of the vertical axis of [001] plane and the exposed {101} facets. With these Mn₃O₄ nano-octahedra as a catalyst, the photodecomposition of rhodamine B is evaluated and it is found that the photodecomposition activity of Mn₃O₄ nano-octahedra is much superior to that of commercial Mn₃O₄ powders. The anomalous magnetic properties and high superior photodecomposition activity of well shaped Mn₃O₄ nano-octahedra should be related to the special shape of the nanoparticles and the abundantly exposed {101} facets at the external surfaces. Therefore, the shape preference can largely broaden the application of the Mn₃O₄ nano-octahedra.
State Key Laboratory of Advanced Technology for Materials, Synthesis and Processing, Wuhan University of Technology, 122 LuoShi Road, Wuhan, Hubei, China.
Yu
Y
Li
Haiyan
H
Tan
Xiao-Yu
XY
Yang
Bart
B
Goris
Jo
J
Verbeeck
Sara
S
Bals
Pierre
P
Colson
Rudi
R
Cloots
Gustaaf
G
Van Tendeloo
Bao-Lian
BL
Su
D008280:Magnetics; D017895:Manganese Compounds / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010087:Oxides / Q000737:chemistry*; D010777:Photochemistry / Q000379:methods*; D011092:Polyethylene Glycols / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry
D017895:Manganese Compounds; D010087:Oxides; D012235:Rhodamines; D011092:Polyethylene Glycols; C027424:manganese oxide; C029773:rhodamine B