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 |Delta G(O*)|, resulting in the balanced adsorption and dissociation of oxygen intermediates, and thus activating O(sic)O. 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.

Automated summary

Metal-free carbon-based materials, such as the synthesized electron-rich carbon nanosheets decorated with pyridinic-N adjacent to carbon vacancies (E-NC-V), have been found to be efficient in boosting the oxygen reduction reaction (ORR) and surpassing the performance of precious metal Pt-based electrocatalysts. The abundant vacancies and d-p orbital hybridization between Zn and N/C in the E-NC-V catalyst contribute to the activation of oxygen intermediates and promote balanced adsorption and dissociation, resulting in enhanced ORR. The assembled Al-air battery using the E-NC-V catalyst exhibits a high peak power density of 113 mW cm(-2). This promising strategy provides insight into the design and fabrication of active sites for enhanced ORR.