Oxygen Reduction Reaction on Graphene in an Electro-Fenton System: In Situ Generation of H2O2 for the Oxidation of Organic Compounds

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• 作者：Chen-Yu Chen ; Cheng Tang ; Hao-Fan Wang ; Prof. Cheng-Meng Chen ; Prof. Xiaoyuan Zhang ; Prof. Xia Huang and Prof. Qiang Zhang
• 刊名：ChemSusChem
• 出版年：2016
• 出版时间：May 23, 2016
• 年：2016
• 卷：9
• 期：10
• 页码：1194-1199
• 全文大小：764K
• ISSN：1864-564X

文摘

Fenton oxidation using an aqueous mixture of Fe²⁺ and H₂O₂ is a promising environmental remediation strategy. However, the difficulty of storage and shipment of concentrated H₂O₂ 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 H₂O₂ 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 Fe²⁺. 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 H₂O₂ through a two-electron pathway. The thermally reduced graphene with a high specific surface area (308.8 m² g⁻¹) and a large oxygen content (10.3 at %) exhibits excellent reactivity for the two-electron oxygen reduction reaction to H₂O₂. 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 H₂O₂.