A Self-Breathing Electrode Enabled by Interface Regulation and Gradient Wettability Engineering for Industrial H2O2 Electrosynthesis

Abstract The development of high-performance gas diffusion electrodes (GDEs) is critical for scalable and sustainable electrochemical H₂O₂ production. However, conventional catalyst layers (CLs) suffer from catalyst encapsulation by fused polytetrafluoroethylene (PTFE) and disordered pore structures, forming a mass transport maze that restricts species diffusion and degrades three-phase interface (TPI) formation. Here, we introduce a non-fused particulate-packed catalyst/binder interface that forms discrete hydrophilic–hydrophobic domains and eliminates the insulating “PTFE armor”. Through 3D reconstruction and high-resolution lattice Boltzmann simulations, we identify that localized variations in wettability and pore structure critically govern electrolyte intrusion and sustaining effective TPIs. Inspired by these insights, we construct a gradient CL featuring hierarchical porosity and precisely tune wettability gradients. Multiscale simulations, in-situ breakthrough pressure measurements, and microfluidic experiments reveal that this gradient design enables directional electrolyte transport and propels H₂O₂ away from CL, maintaining stable Faradaic efficiency (> 85%) at 300 mA cm⁻ ² over 300 hours. Moreover, we develop a commercialized scale-up 400 cm² four-unit flow-through cell stack integrated with thermal, fluidic, and electronic systems, capable of continuously producing H₂O₂ at a low cost ($0.381 kg⁻ ¹) without external oxygen. We demonstrate that catalyst/binder interfaces govern microscale mass transport and TPI formation, with ordered porosity and wettability gradients synergistically boosting electrode performance. This work provides a fundamental design framework for next-generation GDEs and showcases a milestone demonstration of a breakthrough integrated self-breathing H₂O₂ electrosynthesis system with compelling commercial viability.