Oxygen Reduction Reaction on Graphene in an Electro‐Fenton System: In Situ Generation of H2O2 for the Oxidation of Organic Compounds. Issue 10 (21st April 2016) - Chen, Chen‐Yu
Abstract: Fenton oxidation using an aqueous mixture of Fe 2+ and H2 O2 is a promising environmental remediation strategy. However, the difficulty of storage and shipment of concentrated H2 O2 and the generation of iron sludge limit its broad application. Therefore, highly efficient and cost‐effective electrocatalysts are in great need. Herein, a graphene catalyst is proposed for the electro‐Fenton process, in which H2 O2 is generated in situ by the two‐electron reduction of the dissolved O2 on the cathode and then decomposes to generate . OH in acidic solution with Fe 2+ . The π bond of the oxygen is broken whereas the σ bond is generally preserved on the metal‐free reduced graphene oxide owing to the high free energy change. Consequently, the oxygen is reduced to H2 O2 through a two‐electron pathway. The thermally reduced graphene with a high specific surface area (308.8 m 2 g −1 ) and a large oxygen content (10.3 at %) exhibits excellent reactivity for the two‐electron oxygen reduction reaction to H2 O2 . A highly efficient peroxide yield (64.2 %) and a remarkable decolorization of methylene blue (12 mg L −1 ) of over 97 % in 160 min are obtained. The degradation of methylene blue with hydroxyl radicals generated in situ is described by a pseudo first‐order kinetics model. This provides a proof‐of‐concept of an environmentally friendly electro‐Fenton process using graphene for the oxygen reduction reaction in an acidic solution to generate H2 O2 . Abstract : Hydroxy Fenton : Graphene‐based electrocatalysts are prepared for the catalysis of the oxygen reduction reaction. Understanding of the molecular behavior and interactions of the catalysts for the in situ formation of H2 O2 results in enhanced reactivity for the electro‐Fenton oxidation of organic compounds.