Synthesis of original spherical α-Ni(OH)2 architectures by microwave-assisted hydrothermal method and their in situ thermal convention to NiO

The original spherical α-Ni(OH)2 architectures with many cubic particles growing from the surface were successfully synthesized by a microwave-assisted hydrothermal method using urea as hydrolysis-controlling agent and polyethylene glycol (PEG) as surfactant. The NiO architectures with similar morphology were obtained by simple thermal decomposition of the precursor α-Ni(OH)2. The as-obtained products were well characterized by XRD, FTIR, TGA, SEM, TEM, UV–Vis and CVs. The experimental results showed that the diameter of spherical α-Ni(OH)2 architectures was in the range of 2–4 μm. The side length of the cubic particles was uniform about 200 nm. The cyclic voltammetric results showed that the reversible behavior of NiO electrode change better with the increasing of the cycle index. The original NiO we have prepared are expected to have good electrochemical behavior.

► We have synthesized spherical NiO with many cubic particles growing from the surface.
► The NiO spherical in shape with a diameter of 2–4 μm.
► The side length of the cubic particle was uniform about 200 nm.
► The NiO electrode shows good quasireversible behavior.