Potent Charge-Trapping for Boosted Electrocatalytic Oxygen Reduction

Metal-free carbon-based materials are considered to be one of the most promising alternatives to precious metal Pt-based electrocatalysts. However, the electrocatalytic activity of heteroatom-modulated carbon rarely reaches the level of metal-based electrocatalysts. Here, electron-rich carbon and abundant pyridinic-N adjacent to C vacancies decorated with carbon nanosheets (E-NC-V) are synthesized and used as the host for boosting efficient oxygen reduction reaction. Rich pyridinic-N structures adjacent to C vacancies work in synergy with electron-rich carbon, which promotes the sharp decrease of |ΔGO*|, resulting in the balanced adsorption and dissociation of oxygen intermediates, and thus activating OO. This can be attributed to the abundant vacancies and d–p orbital hybridization between Zn and N/C. The E-NC-V catalyst drives the oxygen reduction reaction (ORR) via a 4e− transfer-dominated pathway with a half-wave potential of 0.87 V versus RHE in the alkaline solution, even superior to Pt/C. The assembled Al–air battery exhibits a high peak power density of 113 mW cm^{−2}. This promising strategy sheds light on the design and fabrication of robust, rich-density, and high-performance active sites for the ORR. The work is expected to inspire future work on the role of electronic structure modulation and defect engineering for enhanced reaction kinetics