Designing highly active nanoporous carbon H2O2 production electrocatalysts through active site identification

Abstract

The electrosynthesis of H2O2 via the 2e(-) oxygen reduction reaction (ORR) is an attractive method for the clean and continuous on-site production of H2O2, for which the development of active and selective electrocatalysts remains a significant challenge. Although carbon nanomaterials have demonstrated promising performance for H2O2 production, the lack of understanding of the active sites and key structural factors has impeded their development. In this work, we have prepared carbon-based model catalysts to investigate the active oxygen functional groups and structural factor. We have identified that the carboxyl group at the edge sites of graphitic carbons is the major active site for the 2e ORR, and the carbonyl group is a secondary active site. The nanoporous carbon catalyst with abundant active edge sites and optimized structure exhibited the highest H2O2 electrosynthesis activity among the carbon-based catalysts reported to date and excellent long-term stability (168 h) with 99% H2O2 faradic efficiency.