چکیده (انگلیسی):

Via a facile ultrasound synthesis from nickel acetate and sodium hydroxide with ionic liquids as the
solvent and template it is possible to obtain nano-b-Ni(OH)2 of various dimensionalities depending on
the reaction conditions with the ionic liquid (IL) being the most important factor. Scanning electron
microscopy (SEM) imaging showed b-Ni(OH)2 to form as nanosheets, nanorods and nanospheres
depending on the IL. ILs with strong to moderate hydrogen bonding capability like [C3mimOH][Tf2N]
(1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonylamide)), [C4mim][Tf2N] (1-
butyl-3-methylimidazolium bis(trifluoromethanesulfonylamide)) and [Edimim][Tf2N] (1-ethyl-2,3-
diemethylimidazolium bis(trifluoromethanesulfonylamide)) lead to the formation of nanosheets whilst
[Py4][Tf2N] (butyl-pyridinium bis(trifluoromethanesulfonylamide)) leads to nanoparticles and [N1888]
[Tf2N] (methyltrioctylammonium bis(trifluoromethanesulfonylamide)) to nanorods. Subsequent
calcination of the materials at elevated temperatures (285–425
C) leads to the conversion of b-Ni(OH)2
to NiO under preservation of the nanostructure. Scanning electron microscopy (SEM), X-ray
diffraction (XRD), TG-DTA, X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray
spectroscopy (EDX) were used to observe the morphology, crystallinity, and chemical composition in
more detail. Mesoporous NiO nanosheets obtained in [C4mim][Tf2N] possess an exceptionally high
surface area of 141.28 m2 g
1 and a pore volume of 0.2 cm3 g
1 at 285
C. As a result of calcination at
425
C the surface area decreased to 92.84 m2 g
1, but the pore volume increased to 0.48 cm3 g
1. In
addition, the product has an extraordinarily high saturation magnetization of 1.38 emu g
1, a
coercivity of 117 Oe and an excellent specific capacitance of 199.4 F g
1 which renders the material
highly interesting for application in supercapacitors