Multiscale design of a 3D GDE breaks mass transport barriers for efficient H2O2 electrosynthesis

Abstract

Mass transport critically governs gas-involving electrochemical systems by controlling reactant accessibility and interfacial dynamics. This study develops a theoretical framework integrating reactor and electrode design to address mass transfer limitations in H₂O₂ synthesis via the two-electron oxygen reduction reaction (2e⁻ ORR). A 3D gas diffusion electrode (GDE) enhances oxygen diffusion and triple-phase interface (TPI) activity through synergistic integration of catalytic layers, hydrophobic microporous layers, and macro-flow channels. The experimental results demonstrate that the electrode structure plays a decisive role in multiphase transport, with 60% improvement in H₂O₂ yield compared to conventional electrode systems. Finite element simulations reveal how cathode-localized bubble dynamics regulate oxygen distribution, while engineered electrolyte flow fields amplify convective transport to boost reaction kinetics. By bridging microscale electrode structuring with macroscale reactor fluidics, this framework systematically overcomes traditional mass transfer barriers. This work establishes a universal paradigm for gas–liquid–solid electrochemical systems, emphasizing that transport optimization requires concurrent electrode microstructure engineering and reactor-level hydrodynamic control.