Microporous N-Doped Carbon Obtained from Salt Melt Pyrolysis of Chitosan toward Supercapacitor and Oxygen Reduction Catalysts

Abstract

The direct carbonization of low-cost and abundant chitosan biopolymer in the presence of salt eutectics leads to highly microporous, N-doped nanostructures. The microporous structure is easily manufactured using eutectic mixture (ZnCl2-KCl) and chitosan. Potassium ions here can act as an intercalating agent, leading to the formation of lamellar carbon sheets, whereas zinc chloride generates significant porosity. Here, we present an efficient synthetic way for microporous carbon nanostructures production with a total nitrogen content of 8.7%. Preliminary studies were performed to show the possibility of the use of such material as a catalyst for supercapacitor and ORR. The textural properties enhanced capacitance, which stem from improved accessibility of previously blocked or inactive pores in the carbon structure, leading to the conclusion that porogen salts and molten salt strategies produce materials with tailor-made morphologies. The synergistic effect of the eutectic salt is seen in controlled porous structures and pore size, and the micropores boosting adsorption ability.