Progress and challenges for electrocatalytic production of hydrogen peroxide

The preparation of Hydrogen peroxide (H2O2) by electrochemical two-electron oxygen reduction reaction (2e- ORR) and water oxidation reaction (2e- WOR) is a highly desirable method that can be green, clean and safe. However, the sluggish reaction kinetics and poor 2e- ORR and WOR selectivity severely limits scale-up applications. To resolve these challenges, research on cost-effective catalysts have been intensively explored, which have made great progress. Herein, we first introduced the fundamental chemistry and catalytic mechanism of ORR and WOR, including the possible reaction pathways, the binding modes of oxygen and water on the catalytic sites, and the energy-barrier diagrams of each stage of the reaction obtained by theoretical calculations. Then, the current progress of catalyst research for electrocatalytic synthesis of H2O2 is discussed. Among them, single-atom catalysts as well as molecular catalysts are the hot spots of current research. Single-atom catalysts can reduce the amount of precious or non-precious metals used, and maintain catalytic activity while reducing costs; meanwhile, molecular catalysts have the advantages of single reaction performance, high selectivity, and clear mechanism, which are easy to design and grasp. Finally, on the basis of previous studies, the remaining challenges and development prospects of the current research on electrocatalytic production of H2O2 are discussed, and suggestions are provided for the development of this field in the future.