Recent advances on electrochemical 2e oxygen reduction reaction for hydrogen peroxide on-site production and beyond

The electroproduction of H2O2 through 2e oxygen reduction reaction (ORR) as an alternative strategy for the conventional anthraquinone process is highly energy-efficient and environment-friendly. Different kinds of electrocatalysts with high selectivity, activity, and stability have been recently reported, and are an essential part of the whole electroproduction process of H2O2. In this review, we expound the ORR mechanism and introduce some methods to screen out potential electrocatalysts through theoretical calculations and experimental verifications. In addition, recent advances in reactor design for large-scale on-site production of H2O2 and integrated systems for electricity-H2O2 co-generation are mentioned. With ideal electrocatalysts and rational reactor design, different concentrations of H2O2 can be obtained depending on the practical applications. Utilizing the solar or chemical energy, it can promote energy efficiency and sustainability of the process. Finally, we make a brief conclusion about recent developments in electrocatalysts, device design, as well as integrated systems, and give an outlook for future research challenges, which are meaningful for advancing the electrochemical on-site production of H2O2 via 2e ORR to the marketplace.