Review of H2O2 generation from O2 electroreduction by gas diffusion electrodes: From homogeneous to heterogeneous electrocatalysis

Abstract

In recent years, electrochemical research has focused on developing an efficient alternative technology for the in-situ generation of hydrogen peroxide (H₂O₂) via the two-electron oxygen reduction reaction (2eORR). This comprehensive review summarizes the most recent advancements in the electrochemical synthesis of H₂O₂, emphasizing the pivotal role of gas diffusion electrodes (GDEs). First, different structures and assembly processes of novel modified GDEs were introduced. The mechanism, fabrication, and representative works of the GDE, were then summarized. Furthermore, the variety of catalyst layers (CL) employed were analyzed, aiming to enhance both the activity and selectivity of the 2eORR process. Subsequently, the review delves into the operational parameters that govern the electrochemical generation of H₂O₂, including critical parameters such as current/potential, gas flow rate, electrolyte type, electrolyte pH, and temperature. These parameters affect the thermodynamics and kinetics of O₂ electroreduction, thereby modulating the yield of H₂O₂. Concludingly, the challenges and opportunities in H₂O₂ production through the 2eORR via GDEs were explored.