A facile synthesis for nitrogen-doped carbon catalyst with high activity of oxygen reduction reaction in acidic media

In this paper, we report a facile method to synthesize a nitrogen-doped carbon catalyst for oxygen reduction reaction (ORR). The catalyst was prepared via subsequent carbonization of the composite aerogel under NH₃ and N₂, which was synthesized by the hydrothermal treatment of resorcinol formaldehyde (RF) and graphene oxide (GO). The research focused on the effect of the heat treatment temperature on the carbon defects, doped nitrogen and ORR activity of the catalyst. The results show that more carbon defects can be formed under a relatively low temperature inside the catalyst which also possesses a high ratio of graphitic nitrogen. Interestingly, the catalyst shows a moderate ORR activity in alkaline (E_1/2 = 0.78 V) but a good ORR activity in acids (E_1/2 = 0.72 V), which should be attributed to its high content of carbon defects or graphitic nitrogen. Moreover, a direct methanol fuel cell with the nitrogen-doped carbon as cathode catalyst was fabricated and tested, which gives peak power densities of 18.27 and 16.14 mW cm⁻² at 4 and 14 M methanol solution, respectively. All the results reveal that the carbonization of RF-GO composite aerogel is a promising facile method to prepare ORR catalysts with high activity.