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

Abstract

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.