Defect‐Engineered Mesoporous Undoped Carbon Nanoribbons for Benchmark Oxygen Reduction Reaction

Abstract

AbstractFor 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.