Active Oxygen Functional Group Modification and the Combined Interface Engineering Strategy for Efficient Hydrogen Peroxide Electrosynthesis

Cathodic catalytic activity and interfacial mass transfer are key factors for efficiently generating hydrogen peroxide (H2O2) via a two-electron oxygen reduction reaction (ORR). In this work, a carbonized carboxymethyl cellulose (CMC)-reduced graphene oxide (rGO) synthetic fabric cathode was designed and constructed to improve two-electron ORR activity and interfacial mass transfer. Carbonized CMC exhibits abundant active carboxyl groups and excellent two-electron ORR activity with an H2O2 selectivity of approximately 87%, higher than that of rGO and other commonly used carbonaceous catalysts. Carbonizing CMC and the agglomerates formed from it restrain the restacking of rGO sheets and thus create abundant meso/macroporous channels for the interfacial mass transfer of oxygen and H2O2. Thus, the as-constructed carbonized CMC-rGO synthetic fabric cathode exhibits exceptional H2O2 electrosynthesis performance with 11.94 mg·h-1·cm-2 yield and 82.32% current efficiency. The sufficient active sites and mass-transfer channels of the cathode also ensure its practical application performance at high current densities, which is further illustrated by the rapid organic pollutant degradation via the H2O2-based electro-Fenton process.