The advancement of catalysts that are both platinum-group-metal (PGM)-free and iron-free is essential for the oxygen reduction reaction (ORR), which is kinetically slow, particularly in anion-exchange membrane fuel cells (AEMFCs). One of the primary obstacles lies in achieving adequate activity and stability within the membrane electrode assembly (MEA) under real-world hydrogen-air operating conditions. Herein, an effective MnN4 site encased within N-doped carbon nanofibers (denoted as MnN4@N-CNFs) is designed for efficient ORR electrocatalysis. Benefiting from the electronic structure modulation of MnN4 moieties through strong interfacial coupling with the carbon matrix, and structural advantages of the 3D hierarchical porosity synergizing with N-doped carbon-MnN4 coordination systems, the as-resultant MnN4@N-CNFs demonstrate a high half-wave potential of 0.89 V, outstanding durability, and impressive methanol tolerance under alkaline environments, outperforming commercial Pt/C and a diversity of reported counterparts. Notably, the engineered catalyst demonstrates remarkable fuel cell performance with a peak power density of 222.0 mW cm-2 during practical AEMFC operation, while maintaining stable operation for over 15 h, representing a 3-fold enhancement over conventional Pt/C-based counterparts. This study establishes fundamental design principles for high-efficiency AEMFCs through atomic-level engineering of precisely coordinated metal-N-C active sites, providing a robust framework for next-generation electrocatalyst development.
Ge et al. (Mon,) studied this question.