Free Energy Relationships in the Electrical Double Layer over Single-Layer Graphene

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• 作者：Jennifer L. Achtyl ; Ivan V. Vlassiouk ; Pasquale F. Fulvio ; Shannon M. Mahurin ; Sheng Dai ; Franz M. Geiger
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：January 23, 2013
• 年：2013
• 卷：135
• 期：3
• 页码：979-981
• 全文大小：214K
• 年卷期：v.135,no.3(January 23, 2013)
• ISSN：1520-5126

文摘

Fluid/solid interfaces containing single-layer graphene are important in the areas of chemistry, physics, biology, and materials science, yet this environment is difficult to access with experimental methods, especially under flow conditions and in a label-free manner. Herein, we demonstrate the use of second harmonic generation to quantify the interfacial free energy at the fused silica/single-layer graphene/water interface at pH 7 and under conditions of flowing aqueous electrolyte solutions ranging in NaCl concentrations from 10^鈥? to 10^鈥? M. Our analysis reveals that single-layer graphene reduces the interfacial free energy density of the fused silica/water interface by a factor of up to 7, which is substantial given that many interfacial processes, including those that are electrochemical in nature, are exponentially sensitive to interfacial free energy density.