Stable H2O2 electrosynthesis at industrially-relevant currents by a membrane-based electrode with high oxygen accessibility

Electrosynthesis of hydrogen peroxide (H2O2) presents a sustainable alternative to the anthraquinone process, while the transition to applying this process at industrial-relevant currents remains a significant challenge. Most studies tried to solve it by catalysts modulations, whereas we found that the accessibility to the gaseous O2, might be the crux of this matter. Herein, we developed a series of membrane-based gas diffusion electrodes (Mem-GDEs) with varied O2 accessibility. Their endurable currents were found to be well correlated with the O2 mass transferability. By constructing high O2-accessible triphasic interfaces, Mem-GDE achieved a recorded current density, 1.4 A cm-2, with the current efficiency higher than 80.6%. It was also verified for the first time that the insufficient O2 triggered a severe flooding problem and thus further deteriorate the O2 mass transfer. This study highlights the importance of O2 accessibility and provides new insights into triphasic interfaces construction for realizing industrial-used H2O2-generated electrodes.