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

Abstract

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 –CO group was the most active component in 2e− ORR followed by the –COOH group. The –CO 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.