Nitrogen and Sulfur Doped Mesoporous Carbons, Prepared from Templating Silica, as Interesting Material for Supercapacitors

摘要

Highly accessible surface area and heteroatom-doping are desired properties for carbon electrode materials to be used in electrochemical supercapacitors. In this paper, nitrogen and sulfur doped carbon materials with wide mesopores (13-14 nm) were synthetized according to a hard template approach by pyrolysis of sucrose, 1,10-phenanthroline or dibenzothiophene as carbon, nitrogen-carbon or sulfur-carbon precursors, respectively. The morphology and dimension of mesopores were induced by sacrificial SiO2 nanoparticles (10-20 nm), which are removed at the end of synthesis by an etching solution to reveal a network of hemispherical pores. The interconnectedpore structure was confirmed by scanning electron microscopy and transmission electron microscopy. X-ray photoemission spectroscopy and elemental analysis confirmed the presence of nitrogen and sulfur functional groups. The prepared materials were fully characterized by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy in 0.5 M H2SO4. Notwithstanding the small surface (200m(2)g(-1)) determined by BET method, the nitrogen doped mesoporous carbon showed high specific gravimetric (similar to 170 F g(-1)) and surface (similar to 835 F m(-2)) capacitances that are comparable to those of materials with much higher surface area (5-10-fold higher).