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Single‐Molecule Measurement of Adsorption Free Energy at the Solid–Liquid Interface
Author(s) -
Zhan Chao,
Wang Gan,
Zhang XiaGuang,
Li ZhiHao,
Wei JunYing,
Si Yu,
Yang Yang,
Hong Wenjing,
Tian ZhongQun
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201907966
Subject(s) - adsorption , molecule , solid surface , langmuir adsorption model , chemistry , surface energy , langmuir , chemical physics , thermodynamics , materials science , computational chemistry , organic chemistry , physics
Adsorption plays a critical role in surface and interface processes. Fractional surface coverage and adsorption free energy are two essential parameters of molecular adsorption. However, although adsorption at the solid–gas interface has been well‐studied, and some adsorption models were proposed more than a century ago, challenges remain for the experimental investigation of molecular adsorption at the solid–liquid interface. Herein, we report the statistical and quantitative single‐molecule measurement of adsorption at the solid–liquid interface by using the single‐molecule break junction technique. The fractional surface coverage was extracted from the analysis of junction formation probability so that the adsorption free energy could be calculated by referring to the Langmuir isotherm. In the case of three prototypical molecules with terminal methylthio, pyridyl, and amino groups, the adsorption free energies were found to be 32.5, 33.9, and 28.3 kJ mol −1 , respectively, which are consistent with DFT calculations.