Tunable nitrogen-doped carbon aerogels as sustainable electrocatalysts in the oxygen reduction reaction

A one pot hydrothermal synthesis towards nitrogen doped organic aerogels with tunable surface area and nitrogen content is presented. The gels were synthesized from a sustainable glucose carbon precursor with 2-pyrrol-carboxaldehyde (PCA) as the nitrogen source and borax mineral as the structure forming agent. The particle size and hence surface area could be tuned from 75 nm down to 15 nm by varying the amounts of borax added. Similarly, the nitrogen content could be adjusted between 2.0 wt% and 5.5 wt% by varying the amount of PCA added to the glucose solution. Electrochemical testing of the nitrogen doped carbon aerogels as non-metal oxygen reduction catalysts revealed increasing activity with higher surface area and higher nitrogen content, as well as excellent long term stability. Our work thereby demonstrates the high potential of hydrothermal carbon materials and also provides a facile approach toward tunable nitrogen doped aerogels which should be useful for a wide range of applications.