Surface Redox Chemistry Regulates the Reaction Microenvironment for Efficient Hydrogen Peroxide Generation

Electrosynthesis has emerged as an enticing solution for hydrogen peroxide (H₂O₂) production. However, efficient H₂O₂ generation encounters challenges related to the robust gas-liquid-solid interface within electrochemical reactors. In this work, we introduce an effective hydrophobic coating modified by iron (Fe) sites to optimize the reaction microenvironment. This modification aims to mitigate radical corrosion through Fe(II)/Fe(III) redox chemistry, reinforcing the reaction microenvironment at the three-phase interface. Consequently, we achieved a remarkable yield of up to 336.1 mmol h^-1 with sustained catalyst operation for an extensive duration of 230 h at 200 mA cm^-2 without causing damage to the reaction interface. Additionally, the Faradaic efficiency of H₂O₂ exceeded 90% across a broad range of test current densities. This surface redox chemistry approach for manipulating the reaction microenvironment not only advances long-term H₂O₂ electrosynthesis but also holds promise for other gas-starvation electrochemical reactions.