Self-templating synthesis of nitrogen-decorated hierarchical porous carbon from shrimp shell for supercapacitors

Abstract

Nitrogen-doped hierarchical porous carbon (HPC) was prepared from shrimp shell using its intrinsic mineral scaffold (CaCO₃) as the self-template combined with KOH activation. The roles of the template removal and KOH activation on the hierarchical porous structure of the obtained HPC were discussed in detail. The as-made HPC with abundant micropores, mesopores and interconnected macropores exhibits high electrochemical performance when used as the supercapacitor electrode. The specific surface area of HPC can be easily controlled via changing the activation temperature, and the natural nitrogen in shrimp shell can be preserved, which favor the final electrochemical property. Attributing to the synergetic electrochemical activity of the accessible porosity and the heteroatom, the hierarchical porous carbon pyrolyzed at 700 °C displays the largest specific capacitance of 348 F g⁻¹ in a 6 M KOH electrolyte. The hierarchical porosity of the obtained carbon provides a well-defined ion pathway and electrolyte reservoir, allowing for rapid ionic transportation. This self-templating method represents a very attractive approach for the scalable production of hierarchical porous carbons from natural biomass containing both nitrogen/carbon sources and intrinsic templates.