Defects Mediated Corrosion in Graphene Coating Layer
Defects Mediated Corrosion in Graphene Coating Layer
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DOI：
10.1021/acsami.7b01539
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发表时间：
2017-04-05
影响因子：
9.5
通讯作者：
Zhao, Kejie
中科院分区：
文献类型：
--
作者：
Lei, Jincheng;Hu, Yaowu;Zhao, Kejie
关于石墨烯涂覆的金属表面的防腐蚀报告了混合结果，而石墨烯由于其低渗透性而用作有效的短期防腐蚀和氧化屏障。石墨烯和金属基底之间的原电池在长期运行中促进了广泛的腐蚀。石墨烯层中的缺陷为氧化物质的渗透提供了途径。我们使用第一性原理理论模型研究了石墨烯中缺陷在防腐蚀中的作用。在高反应性环境中的实验表明，氧化产物主要沿石墨烯的晶界沿着。基于密度泛函理论对S和O在石墨烯晶界上的吸附进行了热力学分析。在空位处插入S和O在能量上是有利的。间隙杂质促进石墨烯的结构转变并显著降低石墨烯层的机械强度。此外，间隙S和O的存在通过增强空位的形成和促进腐蚀性反应物沿晶界沿着分散生长来降低石墨烯的化学稳定性。
Mixed results were reported on the anticorrosion of graphenecoated metal surfaces while graphene serves as an effective short-term barrier against corrosion and oxidation due to its low permeability. to gases,, the galvanic cell, between graphene and the, metal substrate facilitates extensive corrosion in the long" run. Defects in the graphene layer provide pathways for the permeation of oxidizing species. We study the role of defects in graphene in the anticorrosion using first-principles theoretical modeling. Experiments in the highly reactive environment indicate that the oxidized products primarily distribute along the grain boundaries of graphene. We analyze the thermodynamics of the absorption of S and O on the grain boundaries of graphene on the basis of density functional theory. The insertion of S and O at the vacancy sites is energetically favorable. The interstitial impurities facilitate structural transformation of graphene and significantly decrease the mechanical strength of the graphene layer. Furthermore, the presence of the interstitial S and Oreduces the chemical stability of graphene by enhancing the of vacancies and promoting dispersive growth of corrosive reactants along the grain boundaries.