Nitrogen-doped porous carbons by conversion of azo dyes especially in the case of tartrazine

Nitrogen-doped porous carbons possessing high surface areas and large pore volumes have been prepared by directly heating the mixture of tartrazine and Ca(OAc)(2)center dot H2O at 800 degrees C especially without further physical or chemical activation, where Ca(OAc)(2)center dot H2O serves as the hard template to regulate the surface area and pore structures. It reveals that the addition of Ca(OAc)(2)center dot H2O can remarkably improve the surface area and total pore volume. The T-Ca-800-3:1 sample displays the highest BET surface area as 1669 m(2) g(-1) and largest total pore volume 0.85 cm(3) g(-1), which is much larger than those without adding Ca(OAc)(2)center dot H2O. Furthermore, it exhibits excellent capacitive performances, including high specific capacitance (ca. 224.3 F g(-1) at 0.5 A g(-1)), good rate capability (the retention of 42.6% at 60 A g(-1)) and good cycling stability (the retention of 92.3% within 5000 cycles). (C) 2013 Elsevier B.V. All rights reserved.