Promoting the Electrochemical Water Oxidation Reaction to H2O2 via Bubbles on the Electrode

Surfacebubbles on the electrode can significantly improvethe electrosynthesis of hydrogen peroxide by a two-electron wateroxidation reaction. Surfacebubbles on electrodes generated via gas evolution reactionare generally considered harmful to the desired electrochemical reactionas they reduce the electrochemically active area and increase energyconsumption. However, it is shown herein that surface bubbles on theelectrode can significantly improve the electrosynthesis of hydrogenperoxide (H2O2) by a two-electron water oxidationreaction (2e-WOR) due to the high concentration of OH- accumulated by the corona of the bubbles. Inspired by this understanding,aerophilic PVDF-coated CFP electrodes were designed to prolong theresidence time of the in situ generated surface bubbles to improvetheir 2e-WOR selectivity from 16.3 to 62.5%, and the H2O2 generation rate was as high as 28.4 & mu;mol min(-1) cm(-2). This study subverts long-heldassumptions about the effect of the bubbles on the electrode towardelectrochemical reaction and provides a theoretical guideline fordesigning 2-WOR catalysts.