Synergy of staggered stacking confinement and microporous defect fixation for high-density atomic FeII-N4 oxygen reduction active sites

The development of high-performance nonprecious metal catalysts (NPMCs) to supersede Pt-based for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells is highly desirable but remains challenging. In this paper, we present a pyrolysis strategy spatial confinement and active-site fixation using iron phthalocyanine (FePc), (Pc) Zn salts as precursors. obtained carbon-based NPMC with hierarchically porous nanostructure thin-layered carbon nanosheets, nearly 100% total Fe species are FeII-N4 active sites. contrast, pyrolyzing FePc alone forms Fe-based nanoparticles embedded amorphous only 5.9% Both experimental characterization density functional theory calculations reveal that through staggered π–π stacking Pc macrocycles effectively prevents demetallation atoms formation via aggregation. Furthermore, Zn-induced microporous defects allow synergistic effect defect results high atomic sites can enhance ORR. optimal FeII-N4-C electrocatalyst outperforms commercial Pt/C catalyst terms half-wave potential, methanol tolerance, long-term stability alkaline media. This modulation greatly advance efforts develop NPMCs.