Nitrogen-doped carbon spheres with precisely-constructed pyridinic-N active sites for efficient oxygen reduction

The intelligent design of non-metallic catalysts with high-performance and long-term stability towards oxygen reduction reaction (ORR) is essentially required for green and sustainable energy conversion systems. Optimizing carbon nanomaterials with abundant and uniformly distributed nitrogen (N)-type active sites provide more advantages for boosting the ORR. However, designing catalysts with well-defined N-doping active sites is extremely challenging using the current methods/techniques. Herein, we report a rational solvothermal strategy to synthesize covalent triazine polymers (CTPs), which act as ideal “all in one” precursors to fabricate N-doped non-metallic catalyst via subsequent pyrolysis. Due to abundant and precisely-constructed pyridinic-N active sites, the newly-realized N-doped carbon spheres (N/N-CS) catalyst exhibits superb catalytic activity for the ORR with a high half-wave potential (E1/2 = 0.865 V vs. RHE), excellent tolerance to methanol and great long-term performance. Impressively, while being utilized as cathode material in primary Zn-air batteries, the N/N-CS electrode performs a superior peak power density (∼148 mW cm−2) to that of commercial Pt/C electrocatalyst (∼123 mW cm−2). This work expands an innovative and high-efficiency method for synthesizing non-metallic electrocatalysts with precisely-controlled active sites offering remarkable catalytic ability towards various energy conversion reactions.