An anti-electrowetting carbon film electrode with self-sustained aeration for industrial H2O2 electrosynthesis

Abstract

Electrochemical two-electron oxygen reduction represents a highly desirable and sustainable future strategy for the mass production of hydrogen peroxide (H₂O₂) for applications from large-scale chemical production to portable sanitation. However, the industrial translation of this process is challenged by poor selectivity and durability due to the damaging flooding of the reactive three-phase interface of air-diffusion electrodes by rapid electrowetting under high current density operation conditions. Here, we demonstrate a concept of an anti-electrowetting carbon film electrode with self-sustained aeration by structurally discontinuously fracturing conventional planar electrocatalyst films assembled using just commercially available carbon particles. The dense through-microcracks formed in the coating-fabricated carbon black-polytetrafluoroethylene active layer counterintuitively present robust underwater hydrophobicity. This allows self-driven diffusion of oxygen from open air to the active interface, while enabling electrodes to operate at industry-relevant current densities (100–300 mA cm⁻²) with unprecedented selectivity (>97%) and durability (>200 h) without failure. The demonstrated anti-electrowetting carbon film with self-sustained aeration is highly promising for developing next-generation cheap and scalable metal-free electrodes for industry-scale H₂O₂ electrosynthesis.