(190h) Enhancing Electrocatalytic H2O2 Production Using Functionalized Carbon Catalysts

The electrocatalytic oxygen reduction reaction (ORR) is a promising method for sustainable and efficient production of hydrogen peroxide (H₂O₂), however achieving high H₂O₂ selectivity, especially in acidic conditions, remains a significant challenge. To address these selectivity issues, significant attention has been on designing highly active and selective carbon-based catalysts owing to their low cost, excellent stability, and tunable physical properties. In addition to modifying material properties, ORR is also strongly impacted by the local catalyst environment, which is controlled by bulk reactor properties (e.g. electrolyte ion composition, pH) and operating conditions (e.g. potential, mass transport). While some local catalyst environment effects have been studied using model Pt electrocatalysts, these effects on other ORR catalysts, such as carbon-based materials, are not widely reported. Therefore, there is a need to improve our fundamental understanding of the relationships between catalyst material, electrolyte composition, and catalytic performance to further enhance overall ORR performance.

In our work, we first systematically assess ORR performance in different reaction environments on a series of boron and nitrogen doped carbon catalysts using a rotating ring disk electrode (RRDE) (Figure 1). By incorporating boron and nitrogen dopants, we find improvements in H₂O₂ selectivity and activity compared to a pristine carbon system, however, there is a noticeable trade-off between optimizing these two performance metrics. Translation to a flow cell device setup equipped with a gas diffusion electrode (GDE) further investigates these performance metrics while providing improved mass transport and higher current densities to mimic a more practical environment for large-scale H₂O₂ production. We monitor the changes in H₂O₂ concentration and Faradaic efficiency for a range of applied potentials over time to evaluate changes in overall performance. The findings of this study provide insight into the development of more robust electrocatalysts as well as strategies to enhance electrocatalytic performance via electrolyte engineering.