2.2. Preparation of Ni(OH)2@GO nanosheets
The 0.1 mg mL-1 GO nanosheets were prepared by
diluting the GO gel and then dispersed by ultrasonication. The
Ni(OH)2 nanosheets were prepared following a previous
method by quickly adding 2-aminoethanol (3.0 mM) aqueous solution into
an equivalent volume of Ni(NO3)2 (2.0
mM) aqueous solution and then aging for 0.5 h at 20 °C. The
Ni(OH)2@GO nanosheets were prepared by mixing the GO
dispersion with the Ni(OH)2 dispersion. The structure of
the three kinds of nanosheets was characterized by atomic force
microscope (AFM, 5500, Agilent Technologies, USA) under the tapping
mode. Transmission electron microscope (TEM, JEM-2100, JEOL, Japan) was
also employed to observe the inner structure. The TEM samples were
prepared by dropping the nanosheets dispersion on a copper grid coated
with a carbon film and drying in air. Moreover, the width distribution
of the nanosheets was measured by dynamic light scattering (DLS,
Autosizer 4700, Malvern, UK) at 20 °C.