Identifying the roles of oxygen-containing functional groups in carbon materials for electrochemical synthesis of H2O2

Electrochemical H2O2 synthesis via a two-electron oxygen reduction reaction (2e ? ORR) has emerged as a promising technology. Carbon-based catalysts with oxygen-containing functional groups exhibit superior performance. However, this process has not been examined experimentally in sufficient detail, and the active oxygen-containing components for 2e ? ORR remain to be properly identified. In this study, the aromatic molecule-modified CNTs with target single oxygen groups were synthesized and used as catalysts to investigate the explicit role of each oxygen group in the 2e ? ORR process. Near-edge X-ray absorption fine structure and cyclic voltammetry demonstrated the existence of strong interactions between the model molecules and CNTs. Electrochemical tests and DFT calculations revealed that the -C--O group was the most active component in 2eORR followed by the -COOH group. The -C--O group with the zigzag and armchair configurations have no apparent influence on the 2e ? ORR performance. This work provides new insights into the nature of active sites on the oxygen-doped carbon catalysts for 2e ? ORR.