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

Abstract

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.

Densely accessible Fe/Co–Nx dual-atom site coupled core–shell Co3Fe7@C as an efficient bifunctional oxygen electrocatalyst for rechargeable zinc–air batteries

“…38–40 On the other hand, the I D / I G ratio, representing the D and G band intensity ratio, emerges as a pivotal indicator elucidating the extent of defects in the material, with a higher I D / I G value suggesting a dominating presence of topological defects. 41 As depicted in Fig. 1d, the I D / I G ratio exhibited a significant increase from the monometallic Fe-NC@900 ( I D / I G = 0.77) to the bimetallic materials, suggesting that the incorporated Co induces defect formation.…”

A review of metal phosphides with catalytic effects in Li–S batteries: boosting the redox kinetics

“…104–108 It has been reported that lithium–sulfur button cells with metal phosphides have good electrochemical properties under different rates and have good cycle stability in soft package batteries. 109–111 The clearly delineated design principles and comprehensive exploration of catalytic mechanisms related to phosphides have offered significant insights for constructing excellent efficiency and long-lasting Li–S batteries. However, numerous areas remain that require persistent investigations into phosphide merchandisers.…”

Recent advances in Fe‐N‐C single‐atom site coupled synergistic catalysts for boosting oxygen reduction reaction

“…Although platinum-based catalysts dominate ORR research, their high cost, limited availability, and vulnerability to methanol poisoning necessitate the exploration of alternative options. 116 Fe-based catalysts, especially those with Fe-N x active sites (SACs), are showing great potential as alternative electrocatalysts. Nevertheless, limitations of Fe-N x single-atom sites have prompted innovative strategies to enhance ORR efficiency.…”