Bioinspired Single‐Atom Sites Enable Efficient Oxygen Activation for Switching Anodic/Cathodic Electrochemiluminescence
Weiqing Xu, Yu Wu, Xiaosi Wang, Ying Qin, Hengjia Wang, Zhen Luo, Jing Wen, Liuyong Hu, Wenling Gu, Chengzhou Zhu
Abstract
Abstract Exploring advanced co‐reaction accelerators with superior oxygen reduction activity that generate rich reactive oxygen species (ROS) has attracted great attention in boosting luminol‐O 2 electrochemiluminescence (ECL). However, tuning accelerators for efficient and selective catalytic O 2 activation to switch anodic/cathodic ECL is very challenging. Herein, we report that enzyme‐inspired Fe‐based single‐atom catalysts with axial N/C coordination structures (FeN 5 , FeN 4 © SACs) can generate specific ROS for cathodic/anodic ECL conversion. Mechanistic studies reveal that FeN 5 sites prefer to produce highly active hydroxyl radicals and afford direct cathodic luminescence by promoting the cleavage of O−O bonds through N‐induced electron redistribution. In contrast, FeN 4 © sites tend to produce superoxide radicals, resulting in inefficient anodic ECL. Benefiting from the enhanced cathodic ECL, FeN 5 SAC‐based immunosensor was constructed for the sensitive detection of cancer biomarkers.