Abstract
We describe the synthesis of hierarchical porous nitrogen-doped carbon nanoparticles with high specific surface area and specific capacitance for supercapacitors. Octapyrrolylnaphthalene (OPN) with eight substituent pyrrolyl groups is used as a reaction precursor and the oxidative product, assigned as POPN, is synthesized in miniemulsion droplets. Further carbonization of POPN at 600℃ (POPN600) and 800℃(POPN800) provides particles with hierarchical porosity, well-defined nanoparticle structure, and high specific surface area. The obtained nitrogen-doped carbon particles POPN800 exhibit a specific capacitance of 156 F g-1 at the scan rate of 2 mV s-1 and 80 F g-1 when the scan rate increases to 100 mV s-1. The high specific capacitance and excellent rate capability can be attributed to the controlled structure of the nanoparticles, hierarchical micro- and mesoporosity, high surface area(365 m2 g-1), and rich nitrogen-doping. The present method allows therefore for the synthesis of nitrogen-doped carbon materials for supercapacitors in an easy one-pot and template-free miniemulsion procedure followed by carbonization.