Covalent triazine framework (CTF) derivatives have emerged as promising metal-free electrocatalysts due to their high nitrogen content and intrinsic porosity. However, their performance remains limited by sluggish interfacial charge transport and the inaccessibility of active sites. Herein, we report an interfacial covalent bridging strategy based on grafting polymerization to construct a carbon heterostructure electrocatalyst, featuring vertically aligned nitrogen-doped nanosheets covalently anchored onto graphene (v-N/CNS/Gr) support. The covalently bridged interface promotes interfacial charge transfer across the heterostructure, activating otherwise dormant nitrogen active sites and amplifying the oxygen reduction reaction (ORR) reactivity. In situ spectroscopic analyses and theoretical simulations reveal that the covalent bridged bonding promotes charge transport and oxygen activation, and optimizes the adsorption/desorption of intermediates, collectively contributing to reduced energy barriers along the 4e- ORR pathway. As a result, the v-N/CNS/Gr delivers excellent ORR activity with a half-wave potential of 0.85 V (vs RHE). When employed as the cathode in a Zn-air battery, v-N/CNS/Gr achieves a high-power density and stable operation over 850 h. This work demonstrates a generalizable triazine-polymer-based interfacial bridge strategy for enhancing active site accessibility and charge transport in metal-free electrocatalysts.

Christopher Ingold Laboratory Department of Chemistry University College London 20 Gordon Street London WC1H 0AJ U K

College of Materials and Chemical Engineering Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials China Three Gorges University Yichang 443002 P R China

College of Materials Science and Engineering Linyi University Linyi 276000 P R China

Department of Engineering Science University of Oxford Parks Road Oxford OX1 3PJ U K

Hubei Key Laboratory of Pollutant Analysis and Reuse Technology College of Chemistry and Chemical Engineering Hubei Normal University Huangshi 435002 P R China

Institute of Technological Sciences Wuhan University Wuhan Hubei 430072 P R China

Key Laboratory of Synthetic and Biological Colloids Ministry of Education School of Chemical and Material Engineering Jiangnan University Wuxi 214122 P R China

Max Planck Institute for Polymer Research Mainz 55128 Germany

Nanotechnology Centre Centre for Energy and Environmental Technologies VŠB Technical University of Ostra va 17 listopadu 2172 15 Ostrava Poruba 708 00 Czech Republic

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