N-Doped hierarchical porous carbon nanoscrolls towards efficient oxygen reduction reaction in Zn–air batteries via interior and exterior modifications

Abstract

Rational design of oxygen reduction reaction (ORR) electrocatalysts is essential for promoting the development of clean energy conversion devices. Herein, we report an in situ sacrificial template strategy combined with external NH₃ activation to controllably prepare etched N-doped hierarchical porous carbon nanoscrolls (EN-PCNS) with excellent ORR activity. Systematic investigation and analysis reveal that the interior and exterior modifications enhance the interaction between the inner and outer sides of EN-PCNS. Benefiting from the unique hierarchical porous structure, much higher number of structural defects, high specific surface area, and diverse N-doping configurations, the delicately designed catalyst shows superior ORR activity (the half potential moves positively to 0.82 V and the limiting current density is 5.15 mA cm⁻²) and Zn–air battery performance (the peak power density reaches 139 mW cm⁻²) than the commercial Pt/C catalyst. This work paves a new way towards the effective design of high-performance carbon-based catalysts for enhancing the ORR and developing clean energy conversion devices.