Bridge-Atom Connected Tiny-Nanosheet Driven Delocalized Electron Transfer on Graphene for 2-Electron Oxygen Reduction Reaction.

Metal-free graphene-based materials are promising alternatives to precious-metal catalysts in the 2-electron oxygen reduction reaction (2e- ORR). While previous research has highlighted the critical role of charge density at active sites, the precise controlling the charge transfer via structural engineering on metal-free graphene remains elusive. In this work, we construct a semi-continuous tiny graphene (SCTG) architecture by a novel isothermal molten-self-assembly strategy, which is composed of nanosized graphene sheets interconnected by a sparse number of bridge atoms. This unique arrangement offers dual advantages: the high density of edge atoms in the small graphene domains facilitates the generation and retention of delocalized electrons, while the minimal bridge atoms reduce electron dissipation pathways, ensuring efficient charge delivery to reactive sites. Notably, this configuration balances electron confinement and mobility-preserving necessary charge routes without enabling excessive leakage. As a result, the SCTG structure elevates the local charge density at catalytic sites to an optimal level, enhancing both oxygen adsorption and electron transfer kinetics. This culminates in a remarkable ORR selectivity of 100% and a production rate of 13.3 mol g-1 h-1 for H2O2. These findings offer valuable insight into how graphene-based structures can be fine-tuned for precise electron control in electrocatalysis.