Birnessite-type MnO2 （δ-MnO2） nano-sheets were successfully synthesized by an interracial synthesis method in this work. The properties and electrochemical performance of the as-prepared δ-MnO2 were analyzed and e...Birnessite-type MnO2 （δ-MnO2） nano-sheets were successfully synthesized by an interracial synthesis method in this work. The properties and electrochemical performance of the as-prepared δ-MnO2 were analyzed and evaluated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption measurement and electrochemical tests. This facile synthesis method enables δ-MnO2 nanosheets to show a large specific surface area （257.5 m^2 g^-1）. The electrochemical test results show that the specific capacitance is 272 F g^-1 and the specific capacitance retention is over 96.7% after 1000 cycles at a scan rate of 10 mV s^-1. All results demonstrate that δ-MnO2 has a great potential application in high- performance electrochemical capacitors, and this interracial synthesis method will be a very promising method to synthesize highly active MnO2 materials in a large scale.展开更多
Acicular goethite（a-Fe OOH） and worm-like maghamite（γ-Fe2O3） nanostructures have been prepared adopting a novel route, using Na2[Fe（HL）2（H2O）2] chelate complex in alkaline medium. It is found that concentrati...Acicular goethite（a-Fe OOH） and worm-like maghamite（γ-Fe2O3） nanostructures have been prepared adopting a novel route, using Na2[Fe（HL）2（H2O）2] chelate complex in alkaline medium. It is found that concentration of hydrated Fe（III） ions increased with increasing temperature, which later play a key role in generation of different phases of iron oxide. Phase and morphology of the products are investigated using XRD, FTIR, SEM, and TEM analysis. Using UV–Vis spectra, various electronic transitions of goethite and maghamite particles are examined. Maghamite nanostructures exhibit superparamagnetic property at room temperature. On the basis of experimental observations and analytical data, growth mechanism of the nanostructures is discussed.展开更多
基金financial support by the One Hundred Talent Program of the Chinese Academy of Sciences and the National Natural Science Foundation of China(No.51302264)
文摘Birnessite-type MnO2 （δ-MnO2） nano-sheets were successfully synthesized by an interracial synthesis method in this work. The properties and electrochemical performance of the as-prepared δ-MnO2 were analyzed and evaluated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption measurement and electrochemical tests. This facile synthesis method enables δ-MnO2 nanosheets to show a large specific surface area （257.5 m^2 g^-1）. The electrochemical test results show that the specific capacitance is 272 F g^-1 and the specific capacitance retention is over 96.7% after 1000 cycles at a scan rate of 10 mV s^-1. All results demonstrate that δ-MnO2 has a great potential application in high- performance electrochemical capacitors, and this interracial synthesis method will be a very promising method to synthesize highly active MnO2 materials in a large scale.
文摘Acicular goethite（a-Fe OOH） and worm-like maghamite（γ-Fe2O3） nanostructures have been prepared adopting a novel route, using Na2[Fe（HL）2（H2O）2] chelate complex in alkaline medium. It is found that concentration of hydrated Fe（III） ions increased with increasing temperature, which later play a key role in generation of different phases of iron oxide. Phase and morphology of the products are investigated using XRD, FTIR, SEM, and TEM analysis. Using UV–Vis spectra, various electronic transitions of goethite and maghamite particles are examined. Maghamite nanostructures exhibit superparamagnetic property at room temperature. On the basis of experimental observations and analytical data, growth mechanism of the nanostructures is discussed.
