Protic-Salt-Derived Nitrogen/Sulfur-Codoped Mesoporous Carbon for the Oxygen Reduction Reaction and Supercapacitors

Nitrogen/sulfur-co-doped mesoporous carbon (Phen-HS) was obtained through direct carbonization of a single protic salt, that is, 1,10-phenanthrolinium dibisulfate ([Phen][2HSO(4)]), in the presence of a colloidal silica template without the use of additional acid or metal catalysts for prepolymerization prior to carbonization. Phen-HS was prepared in a relatively high yield (30.0%) and has a large surface area (1161m(2)g(-1)), large pore volume (2.490cm(3)g(-1)), large mesopores (approximate to 12nm), narrow pore-size distribution (7-16nm), and high nitrogen (7.5at%) and sulfur (1.3at%) contents. The surface area/pore-size distribution is much higher/narrower than that of most reported carbon materials obtained from traditional precursors by using the same template. Phen-HS was directly used as an electrocatalyst for the oxygen reduction reaction (ORR) and as an electrode material for supercapacitors. As an efficient metal-free catalyst, Phen-HS exhibited good electrocatalytic activity toward the ORR in a 0.1M KOH aqueous solution, which is comparable to the activity of a commercial Pt/C catalyst. Electrochemical measurements for Phen-HS used in a double-layer capacitor showed high specific capacitances of 160 and 140Fg(-1) in 1M H2SO4 and 6M KOH, respectively, with good rate capabilities and high cycling stabilities.