Synthesis, Characterization, and Magnetic Properties of Uniform-sized MnO Nanospheres and Nanorods Jongnam Park,† Eunae Kang,† Che Jin Bae,‡ Je-Geun Park,‡ Han-Jin Noh,§ Jae-Young Kim,§ Jae-Hoon Park,§ Hyun Min Park,| and Taeghwan Hyeon*, National CreatiVe Research InitiatiVe Center for Oxide Nanocrystalline Materials and School of Chemical Engineering, Seoul National UniVersity, Seoul 151-744, Korea, Department of Physics and Institute of Basic Sciences, Sungkyunkwan UniVersity, Suwon 440-746 Korea, Department of Physics and Pohang Acceleration Laboratory, Pohang UniVersity of Science and Technology, Pohang, Kyungbuk 790-784, Korea, and New Material EValuation Center, Korea Research Institute of Standards and Science, Taejon 305-600, Korea ReceiVed: April 22, 2004; In Final Form: July 5, 2004 報告人：許祐元 指導教授：王聖璋 J. Phys. Chem. B 2004, 108, 13594-13598

Introduction MnO2 is currently under extensive investigations for its capacitance properties. manganese oxide nanostructures for their potential applications such as catalysis, rechargeable batteries, ionsieves and supercapacitors the synthesis of MnO nanospheres and nanorods from the thermal decomposition of Mn-surfactant complexes

Experimental complex Stirring At 300℃ for 1hr Mn2(CO)10 Stirring 0.2 g Trioctylphosphine(TOP) 10 mL complex Oleylamine 2 mL Triphenylphosphine(TPP) 10 mL J. Phys. Chem. B 2004, 108, 13594-13598

Results and discussion Inject TPP Inject TOP Inject TOP At 100℃ for 2 days Figure 1. Transmission electron micrograph of 5-, 10-, and 40-nm monodisperse MnO nanoparticles. J. Phys. Chem. B 2004, 108, 13594-13598

Figure 2. Low-resolution transmission electron micrographs of Inject TOP At 330℃ Inject TPP At 330℃ Figure 2. Low-resolution transmission electron micrographs of (a) 7 x 33 nm and (b) 8 x 140 nm sized MnO nanorods, (c) high-resolution transmissionelectron micrograph, and (d) electron diffraction pattern of 8 140 nm sized MnO nanorods. J. Phys. Chem. B 2004, 108, 13594-13598

Figure 4. The powder X-ray diffraction (XRD) pattern of 8 140 MnO (JCPDS, 07-0230) MnO (JCPDS, 89-4835) M3O4 (JCPDS, 80-0382) Figure 4. The powder X-ray diffraction (XRD) pattern of 8 140 nm sized MnO nanorods.

Conclusion we synthesized uniform-sized MnO nanospheres with particle sizes ranging from 5 to 40 nm from the thermal decomposition of Mn-surfactant complexes. When TOP and TPP were employed as the surfactants, MnO nanorods with sizes of 7 nm (diameter) x 33 nm (length) and 8 nm (diameter) x 140 nm (length) were produced

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