Easy and controlled synthesis of nitrogen-doped carbon

A novel synthesis of N-doped carbon with not only a high surface area (similar to 1000 m(2) g(-1)) but also with a controlled amount of N-doping is reported from the solvothermal reduction of hexachlorobenzene (HCB) and pentachloropyridine (PCP), without the emission of harmful byproducts. In the presence of metallic sodium as a reducing agent, the N-doping amount can be regulated up to 0.12 of N/C atomic ratio by simply altering the initial HCB and PCP ratios. The mechanism is proposed where the chlorine in the HCB and PCP is reacted with metallic sodium by producing NaCl, and the N-doped carbon is synthesized as the activated carbon edges of C5N and C-6 rings being bonded together. The surfaces of the prepared N-doped carbons are modified through heat-treatment and this dramatically improves the mechanical and electrical properties. The dominant doping phases of N are pyridinic-N and amide or amine groups; however, the amide or amine groups are eliminated and graphitic-N is newly generated through heat-treatment. (C) 2012 Elsevier Ltd. All rights reserved.