Nitrogen-doped porous carbon foams prepared from mesophase pitch through graphitic carbon nitride nanosheet templates

A scalable and facile method was developed to synthesize nitrogen-doped porous carbon foams (NDPCFs) using graphitic carbon nitride (g-C₃N₄) nanosheets as hard templates through the calcination of mesophase pitch. The morphology, structure, chemical composition and electrochemical performance of the as-prepared NDPCFs were characterized and investigated. The results show that NDPCFs are fabricated from crimpled and folded carbon nanosheets and have a three-dimensional interconnected structure. The carbon nanosheets show a certain degree of orientation of graphite crystallites. The specific surface area, wall thickness and nitrogen content are controllable by tuning the mass ratio of g-C₃N₄ nanosheets to mesophase pitch. The content of nitrogen species, most of which are quaternary-N and pyridinic-N components, significantly decreases from 6.48 to 0.74 at% with raising calcination temperature from 800 to 1600 °C. The NDPCFs prepared at 800 °C have a high specific surface area of 2098 m² g^-1, an ultra-large pore volume of 5.048 cm³ g^-1 and a high nitrogen content of 6.48 at%. Furthermore, this material exhibits remarkable electrochemical performance as an electrode material for supercapacitors with a specific capacitance of 125.6 F g^-1 even at a high scan rate of 200 mV s^-1.