Nitrogen Self-Doped Hierarchical Porous Carbon from Myriophyllum Aquaticum for Supercapacitor Electrode

Nitrogen self-doped carbon with hierarchical porous structure was fabricated via a simple but highly efficient method, where an aquatic plant myriophyllum aquaticum was used as both carbon and nitrogen precursors. The obtained carbons had 2.3 similar to 3% nitrogen content which was self-doped attributing to the high nitrogen content of myriophyllum aquaticum, thus eliminating the need of extra nitrogen addition. It discovered that KHCO3 was more efficient than traditional widely used CO2 to generate porous carbons (total surface areas 1765 vs 1003 m(2)/g). Hierarchical porous structure with macro-, meso- and micro-pores could be formed with the use of KHCO3 instead of CO2 (only micro- and meso-pores in the carbon). The myriophyllum aquaticum derived carbons were applied for the electrodes of supercapacitor, and the electrochemical performance of the KHCO3 activated carbons was superior to that of CO2 activated carbons (248 F/g vs 199 F/g). The excellent performance of myriophyllum aquaticum derived carbons via KHCO3 activation could be attributed to its unique surface functionalities and pore structures including nitrogen containing groups, high surface area and hierarchical structure. The outcomes of this work offer a low cost and scalable approach to prepare nitrogen self-doped porous carbons from discarded myriophyllum aquaticum.