Synthesis of porous nanocrystalline NiO with hexagonal sheet-like morphology by homogeneous precipitation method

•An easy method is employed for the synthesis of porous nanocrystalline NiO on a large scale.•Morphology, specific surface area and optical band gap are affected by the calcination temperature.•The catalytic activity of the synthesized samples was tested for the reduction of 4-nitrophenol.

Porous nanocrystalline NiO has been synthesized by a simple homogeneous precipitation method in short time at low calcination temperature without using any surfactant, chelating or gelating agents. The porous nanocrystalline NiO with a hexagonal sheet-like morphology were obtained by calcination of Ni(OH)2 nanoflakes at 500 °C. The calcination temperature strongly influences the morphology, crystallite size, specific surface area, pore volume and optical band gap of the samples. The samples were characterized using powder X-ray diffraction, thermal gravimetric analysis, FT-IR spectroscopy, UV–Visible diffuse reflectance spectroscopy, surface area measurements, field emission scanning electron microscopy coupled with energy dispersive X-ray analysis and transmission electron microscopy. The chemical activity of the samples was tested by catalytic reduction of 4-nitrophenol with NaBH4.

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