Effect of carbothermal reduction on the microstructures of porous carbons from the mixture of coal-tar pitch and nano-MgO

•Carbothermal reduction between nano-MgO and porous carbons occurs at high temperatures.•The carbothermal reduction greatly influences the microstructures of resulting porous carbons.•The porous carbons prepared possess higher specific surface area with less mesopore volume.

Porous carbons were prepared by pyrolysis of the mixture of coal-tar pitch and nano-MgO, and the effect of carbothermal reduction between nano-MgO and carbons on their microstructures was studied. Pyrolysis behavior of the mixture was characterized by simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC) and X-ray diffraction (XRD). In addition, the microstructures of resulting porous carbons were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and nitrogen adsorption-desorption measurement. Results show that the carbothermal reduction occurs when the temperature is beyond 1300 °C, greatly influencing the microstructures of the resulting porous carbons. With the increasing of temperature, the porous carbon prepared possesses a thinner thickness of pore wall and a higher specific surface area with a less mesopore volume. When the temperature arrives at 1800 °C, the porous carbon prepared exhibits three-dimensional network structures consisting of few-layered graphene sheets.