Template-free synthesis of hierarchical peanut-like Co and N codoped porous carbon with highly efficient catalytic activity for oxygen reduction reaction

Studies have shown that the performance of electrode materials greatly depends on their structures and compositions. Herein, unique hierarchical peanut-like Co and N codoped porous carbon (Co/N-PC) had been synthesized by using inexpensive melamine, formaldehyde and cobalt acetate as raw materials via a simple template-free hydrothermal reaction followed by heat treatment. The formation process of the peanut-like precursor was discussed in-depth, indicating that the morphological evolution with time followed a pathway of: solid microspheres -> wrinkled and ultrathin shells wrapped microspheres -> the peanut-like precursor formation. Furthermore, the unique structure combines the advantageous features of high surface area, sufficient active sites, easy access to medium and rapid mass transport. As a result, the peanut-like Co/N-PC showed high catalytic activity, superior methanol crossover resistance and excellent catalytic stability towards oxygen reduction reaction (ORR) in alkaline medium. Notably, the peanut-like Co/N-PC possessed a comparable ORR half-wave potential to commercial 20 wt% Pt/C catalyst. Therefore, it can be expected that the peanut-like Co/N-PC will be a promising alternative to commercial Pt/C catalyst for fuel cells. (C) 2015 Elsevier Ltd. All rights reserved.