Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University , Tianjin 300071, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210023, China.
Environ Sci Technol. 2017 Aug 1;51(15):8597-8605. doi: 10.1021/acs.est.7b01762. Epub 2017 Jul 21.
Graphene is easily warped in the out-of-plane direction because of its high in-plane Young's modulus, and exploring the influence of wrinkled graphene on its properties is essential for the design of graphene-based materials for environmental applications. Herein, we prepared wrinkled graphene (WGN-1 and WGN-2) by thermal treatment and compared their electrochemical properties with those of flat graphene nanosheets (FGN). FGN exhibit activities that are much better than those of wrinkled graphene nanosheets (WGN), not only in the electrochemical oxidation of methylene blue (MB) but also in the electrochemical reduction of nitrobenzene (NB). Transformation ratios of MB and NB in FGN, WGN-1, and WGN-2 were 97.5, 80.1, and 57.9% and 94.6, 92.1, and 81.2%, respectively. Electrochemical impedance spectroscopy and the surface resistance of the graphene samples increased in the following order: FGN < WGN-1 < WGN-2. This suggests that the reaction charges transfer faster across the reaction interfaces and along the surface of FGN than that of WGN, and wrinkles restrict reaction charge transfer and reduce the reaction rates. This study reveals that the morphology of the graphene (flat or wrinkle) greatly affects redox reaction activities and may have important implications for the design of novel graphene-based nanostructures and for our understanding of graphene wrinkle-dependent redox reactions in environmental processes.
由于其高面内杨氏模量，石墨烯很容易在面外方向变形，探索皱石墨烯对其性能的影响对于设计用于环境应用的基于石墨烯的材料至关重要。在此，我们通过热处理制备了皱石墨烯（WGN-1 和 WGN-2），并将其电化学性质与平石墨烯纳米片（FGN）进行了比较。FGN 表现出比皱石墨烯纳米片（WGN）更好的活性，不仅在亚甲基蓝（MB）的电化学氧化中，而且在硝基苯（NB）的电化学还原中也是如此。在 FGN、WGN-1 和 WGN-2 中，MB 和 NB 的转化比分别为 97.5%、80.1%和 57.9%和 94.6%、92.1%和 81.2%。电化学阻抗谱和石墨烯样品的表面电阻按以下顺序增加：FGN <WGN-1< WGN-2。这表明反应电荷在 FGN 上比 WGN 更快地穿过反应界面和沿表面转移，而褶皱限制了反应电荷转移并降低了反应速率。这项研究表明，石墨烯的形态（平的或皱的）极大地影响了氧化还原反应活性，这对于设计新型基于石墨烯的纳米结构以及理解环境过程中石墨烯褶皱依赖的氧化还原反应具有重要意义。
