Designing New Anodic Hydrogen Peroxide Generation System with Acidic CO2-Mediated Two-Electron Water Oxidation

Hydrogen peroxide (H2O2) has a wide range of applications in various industries, including bleaching, water treatment, and chemical synthesis. However, traditional anthraquinone process for producing hydrogen peroxide is not sustainable, making researchers to explore alternative methods. In this context, electrochemical production of H2O2 is gaining attention. Particularly, unlike the two-electron oxygen reduction that requires gaseous oxygen, the two-electron water oxidation at the anode only needs water. This reaction allows for the conversion of renewable electrical energy into chemical energy in the form of O-O bonding on the electrode surface. However, it faces challenges from the competing four-electron water oxidation reaction, which produces oxygen instead of hydrogen peroxide. Therefore, optimizing the system design, including the selection of appropriate electrode materials and operating conditions, is crucial to improve the selectivity and efficiency of the two-electron water oxidation process.<br/>In this study, we explore an approach to anodic hydrogen peroxide generation by employing an acidic environment facilitated by a carbon dioxide (CO2)-based electrolyte. Using fluorine-doped tin oxide (FTO) as the anode material, we aimed to enhance the stability and faradaic efficiency of hydrogen peroxide production. Our electrochemical analysis results demonstrate that the use of a carbon dioxide (CO2)-based acidic electrolyte system performs as effectively as the previously used basic carbonate electrolyte. This approach resulted in improved stability of the generated hydrogen peroxide and better faradaic efficiency.<br/>Our findings indicate that the carbon dioxide-mediated acidic electrolyte environment achieves production rates comparable to those of traditional carbonate-based systems while offering enhanced stability. This finding provides valuable insights into the design of more effective anodic systems, potentially advancing the commercial viability of electrochemical hydrogen peroxide generation technologies.