Chen Chen-Yu, Tang Cheng, Wang Hao-Fan, Chen Cheng-Meng, Zhang Xiaoyuan, Huang Xia, Zhang Qiang
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, PR China.
Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, 27 Taoyuan South Road, Taiyuan, 030001, PR China.
ChemSusChem. 2016 May 23;9(10):1194-9. doi: 10.1002/cssc.201600030. Epub 2016 Apr 21.
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 .
使用Fe(2+)和H2O2的水性混合物进行芬顿氧化是一种很有前景的环境修复策略。然而，浓H2O2储存和运输的困难以及铁污泥的产生限制了其广泛应用。因此，迫切需要高效且经济高效的电催化剂。在此，提出了一种用于电芬顿过程的石墨烯催化剂，其中H2O2通过溶解在阴极上的O2的双电子还原原位生成，然后在酸性溶液中与Fe(2+)分解生成(.)OH。由于高自由能变化，氧的π键断裂，而σ键通常保留在无金属还原氧化石墨烯上。因此，氧通过双电子途径还原为H2O2。具有高比表面积(308.8 m(2) g(-1))和高氧含量(10.3 at%)的热还原石墨烯对H2O2的双电子氧还原反应表现出优异的反应活性。在160分钟内获得了高效的过氧化物产率(64.2%)和超过97%的亚甲基蓝(12 mg L(-1))显著脱色。用原位生成的羟基自由基降解亚甲基蓝用伪一级动力学模型描述。这为使用石墨烯在酸性溶液中进行氧还原反应以生成H2O2的环境友好型电芬顿过程提供了概念验证。
