Hierarchical hydrothermal carbon interface microenvironment engineering for High-Rate H₂O₂ electrosynthesis from air in acidic media

Electrochemical hydrogen peroxide (H₂O₂) synthesis via the two-electron oxygen reduction reaction (2e^- ORR) offers a green alternative to the industrial anthraquinone process, yet scalability remains challenged by severe O₂ mass transport limitations in conventional systems. Herein, we report a holistic electrode engineering strategy that synergistically combines a biomass-derived hydrothermal carbon (HTC) catalyst with a rationally designed air-diffusion electrode (ADE). We employ a sustainable HTC catalyst, where DFT calculations identify its inherent oxygen functional groups (OFGs) as active sites for stabilizing the *OOH intermediate. The catalyst is integrated into a durable hydrophobic scaffold composed of polytetrafluoroethylene (PTFE)-coated macroporous carbon felt, establishing a stable three-phase interface. Crucially, we demonstrate that optimizing HTC catalyst loading on this hydrophobic support balances active site density with unimpeded gas transport. Supported by in-situ Raman spectroscopy which confirms reactant accumulation at the interface, our optimized ADE delivers an exceptional H₂O₂ production of 975.65 mg L^-1 at 200 mA cm⁻² with 98.7 % Faradaic efficiency. This work establishes a synergistic design principle, coupling a sustainable, intrinsically active catalyst with a structurally engineered microenvironment to enable practical, high-current H₂O₂ electrosynthesis.