For large-scale fuel cell applications, it is significant to replace expensive Pt-based oxygen reduction reaction (ORR) electrocatalysts with nonprecious metal- or metal-free carbon-based catalysts with high activity. However, it is still challenging to deeply understand the role of intrinsic defects and the origin of ORR activity in pure nanocarbon. Therefore, a novel self-assembly and a pyrolysis strategy to fabricate defect-rich mesoporous carbon nanoribbons are presented. Due to the effective regulation of nanoarchitecture, a vast number of defective catalytic sites (edge defects and holes) are exposed, which thereby enhances the electron transfer kinetics and catalytic activity. Such undoped nanoribbons display a large half-wave potential of 0.837 V, excellent long-term stability, and exceptional methanol tolerance, surpassing the most undoped ORR catalysts and the commercial Pt/C (20 wt.%) catalyst. Structural characterizations and density functional theory (DFT) calculations confirm that the zigzag edge defects and the armchair pentagon at the hole defect are responsible for outstanding ORR performance.
Keywords: defect engineering; density functional theory calculations; dopant-free nanocarbons; intrinsic defects; oxygen reduction reaction.
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