在单层石墨烯的电双层与单层石墨烯之间的自由能量关系
Jennifer L Achtyl1, Ivan V Vlassiouk, Pasquale F Fulvio
1Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|January 10, 2013
概括
单层石墨烯在化/水接口上的界面自由能量显著减少,高达七倍. 这一发现对于在流量条件下理解化学和材料科学界面过程至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 表面科学是一门学科.
背景情况:
- 使用单层石墨烯的流体/固体接口在各种科学学科中至关重要.
- 对这些接口的实验研究,特别是在流下和没有标签的情况下,提出了重大挑战.
研究的目的:
- 要量化化/单层石墨烯/水接口的界面自由能量.
- 为了研究流动的水性电解质溶液对这种接口的影响.
主要方法:
- 使用第二波代 (SHG) 进行无标签量化.
- 在pH 7下,在流动的水性电解质溶液下研究的接口具有不同的NaCl度 (10^-4到10^-1M).
主要成果:
- 发现单层石墨烯可以将化/水接口的界面自由能量密度降低高达7的系数.
- 这种减少是相当大的,并影响了接口过程,包括电化学过程.
结论:
- 二次波生成提供了一种可行的方法,用于研究在流下基于石墨烯的系统的界面特性.
- 石墨烯显著减少界面自由能量,这对控制不同应用中的界面现象具有广泛的影响.
相关概念视频
The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
Electric Field of Parallel Conducting Plates
Gauss' law relates the electric flux through a closed surface to the net charge enclosed by that surface. Gauss's law can be applied to find the electric field and the charge enclosed in a region depending on its charge distribution.
Consider a cross-section of a thin, infinite conducting plate having a positive charge. For such a large thin plate, as the thickness of the plate tends to zero, the positive charges lie on the plate's two large faces. Without an external electric field, the...
Consider a cross-section of a thin, infinite conducting plate having a positive charge. For such a large thin plate, as the thickness of the plate tends to zero, the positive charges lie on the plate's two large faces. Without an external electric field, the...
Electrostatic Boundary Conditions
Consider an external electric field propagating through a homogeneous medium. When the electric field crosses the surface boundary of the medium, it undergoes a discontinuity. The electric field can be resolved into normal and tangential components. The amount by which the field changes at any boundary is given by the difference between the field components above and below the surface boundary.
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
Free Energy and Equilibrium
The free energy change for a process may be viewed as a measure of its driving force. A negative value for ΔG represents a driving force for the process in the forward direction, while a positive value represents a driving force for the process in the reverse direction. When ΔGrxn is zero, the forward and reverse driving forces are equal, and the process occurs in both directions at the same rate (the system is at equilibrium).
Recall that Q is the numerical value of the mass action expression...
Recall that Q is the numerical value of the mass action expression...
Free Energy and Equilibrium
The free energy change for a process may be viewed as a measure of its driving force. A negative value for ΔG represents a driving force for the process in the forward direction, while a positive value represents a driving force for the process in the reverse direction. When ΔG is zero, the forward and reverse driving forces are equal, and the process occurs in both directions at the same rate (the system is at equilibrium).
The reaction quotient, Q, is a convenient measure of the status of an...
The reaction quotient, Q, is a convenient measure of the status of an...
Energy Associated With a Charge Distribution
The work done to bring a charge through a distance r is given by the potential difference between the initial and the final position. To assemble a collection of point charges, the total work done can be expressed in terms of the product of each pair of charges divided by their separation distance, defined with respect to a suitable origin. Solving this expression gives the energy stored in a point charge distribution.


