Electrosynthesis of H2O2 via two-electron oxygen reduction over carbon-based catalysts: From microenvironment control to electrode/reactor design

The electrochemical production of hydrogen peroxide (H2O2) by the two-electron oxygen reduction (2e−-ORR) process has the advantages of high safety, low energy consumption, and environmental friendliness. For 2e−-ORR, the catalyst/electrode is the key component as it strongly affects catalytic performance and cost. Carbon materials have the advantages of high electronic conductivity, good structural stability, easy control of nanostructures, and low cost. Therefore, it has been regarded as a promising catalyst/electrode material for the electrosynthesis of H2O2 via 2e−-ORR. In addition, studies have also considered the optimization of the liquid/gas interface by tuning the electrode surface, electrolyte pH, and reactor configurations for further improving the activity and selectivity of catalysts. In this review, we provide an in-depth discussion of the recent research on the carbon-based electrocatalysts for 2e−-ORR, especially in terms of microenvironment tuning, catalyst/electrode interface engineering, and reactor design for achieving stable and efficient production of H2O2. The challenges that we are still facing and the future development prospects will then be concluded, which we believe should help the future development in this field.