Built-in electric field induced by defected carbons adjacent to graphitic nitrogen valley for efficient oxygen reduction reaction and zinc-air batteries

Rational design of defected carbons adjacent to nitrogen (N) dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon. Meanwhile, the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction (ORR) ability of inactive carbons through charge redistribution. Herein, we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the two-dimensional (2D) mesoporous N-doped carbon nanoflakes (NCNF) is a promising technique for improving ORR performance. As a result, the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts. Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site, rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR. Also, NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of ∼121.10   mW cm −2 and ∼679.86 mA h g Zn −1 , respectively. This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.