Characterizations
Scanning electron microscope (SEM, Camscan Mx2600FE) and
transmission electron microscope (TEM, JEM-2010) were used
to observe the morphologies of SSG and MnO2. X-ray Diffraction
(XRD, a D/MAX-2500 PC made in Japan) was performed
with Cu Ka radiation (l z 0.154 nm). Raman spectra were
recorded on a Renishaw Raman microscope (the excitation
wavelength at 514.5 nm). BrunauereEmmetteTeller (BET)
surface area was measured by using a NOVE 4000e analyzer. In
order to examine the mass percentages of MnO2, thermogravimetry
(TG) experiments were performed in air flow from
30 to 900 C using a simultaneous thermal analyzer
(STA 449C).