Ordered nitrogen doped mesoporous carbon assembled under aqueous acidic conditions and its electrochemical capacitive properties

Abstract

With urea as nitrogen source, soluble phenol–urea–formaldehyde (PUF) resin is synthesized under basic conditions, and then an N-containing mesophase is obtained by co-assembly of the obtained PUF resin and block copolymer of F127 in acidic aqueous solution. The pyrolysis of the resultant mesophase in inert atmosphere produces a nitrogen-doped mesoporous carbon, which possesses a well-defined ordered mesoporous structure, large surface area (up to 537m2/g), uniform pore size (∼3.6nm) and large pore volume (∼0.49cm3/g). Multi-techniques, such as elemental analysis, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS) are performed to characterize the samples; these analytic results indicate that the doped nitrogen mainly exists as pyridinic and pyrrolic nitrogen is successfully and homogeneously introduced into the skeleton of the mesoporous carbon. And more, the nitrogen content in the final ordered mesoporous carbon can be easily adjusted up to 3.85 wt.% by increasing the original ratio of urea to phenol. Electrochemical measurements show the nitrogen doped mesoporous carbon presents a higher specific capacitance (up to 225F/g) than nitrogen-free ones (169F/g) and exhibits a good electrochemical stability even after 1000 cycles at current density of 5.0A/g.