Edge‐hosted Atomic Co−N 4 Sites on Hierarchical Porous Carbon for Highly Selective Two‐electron Oxygen Reduction Reaction

作者：Yuhui Tian, Meng Li, Zhenzhen Wu, Qiang Sun, Ding Zhong Yuan, Bernt Johannessen, Li Xu, Yun Wang, Yuhai Dou, Huijun Zhao, Shanqing Zhang · 发表于：Angewandte Chemie International Edition · 年份：2022 · DOI：10.1002/anie.202213296 · 被引用次数：188 · 研究领域：Electrocatalysts for Energy Conversion、Advanced Photocatalysis Techniques、Fuel Cells and Related Materials

Abstract Not only high efficiency but also high selectivity of the electrocatalysts is crucial for high‐performance, low‐cost, and sustainable energy storage applications. Herein, we systematically investigate the edge effect of carbon‐supported single‐atom catalysts (SACs) on oxygen reduction reaction (ORR) pathways (two‐electron (2 e − ) or four‐electron (4 e − )) and conclude that the 2 e − ‐ORR proceeding over the edge‐hosted atomic Co−N 4 sites is more favorable than the basal‐plane‐hosted ones. As such, we have successfully synthesized and tuned Co‐SACs with different edge‐to‐bulk ratios. The as‐prepared edge‐rich Co−N/HPC catalyst exhibits excellent 2 e − ‐ORR performance with a remarkable selectivity of ≈95 % in a wide potential range. Furthermore, we also find that oxygen functional groups could saturate the graphitic carbon edges under the ORR operation and further promote electrocatalytic performance. These findings on the structure–property relationship in SACs offer a promising direction for large‐scale and low‐cost electrochemical H 2 O 2 production via the 2 e − ‐ORR.