Onion‐Like Carbon Nanozyme: Controlling Peroxidase‐Like Activity by Carbon Hybridization Patterns for Antibacterial Therapy

Abstract Since the inception of the concept of nanozymes, there has been a growing interest in the rational design and controllable synthesis of nanozymes with adjustable activities. In this study, onion‐liked carbon (OLC) with remarkable peroxidase‐like (POD) activity are developed through delicately controlling the sp 2 /sp 3 configuration. The investigation reveals that enzymatic activity of OLC increases first and then decreases with the increased graphitic degree, with the highest activity observed at a moderate sp 2 /sp 3 ratio of 17.17%. A series of experiments and theoretical calculations are conducted to elucidate the catalytic mechanism, and the structure‐dependent activity is attributed to a synergistic effect of surface adsorption and electron transfer processes. The POD activity enables the OLC to catalyze the decomposition of H 2 O 2 , producing reactive oxygen species for eradicating Gram‐positive and Gram‐negative bacteria. Additionally, toxicity tests based on nematode and mouse models confirmed the excellent biocompatibility of OLC. Furthermore, the OLC exhibited antibacterial ability and promoted bacterial‐infected wound healing in a mouse model. This work not only gives a deeper understanding of the structure‐activity relationship and catalytic mechanism of carbon‐based nanozymes, but also unveils a novel avenue for antibacterial therapy and wound healing applications.