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Interfacial Acidity on Oxide Surfaces: A Scaling Paradigm and the Role of the Hydrogen Bond

preprint
submitted on 08.04.2020 and posted on 09.04.2020 by Robert Chapleski, Azhad U. Chowdhury, Kyle Mason, Robert Sacci, Benjamin Doughty, Sharani Roy

A fundamental understanding of acidity at an interface, as mediated by structure and molecule-surface interactions, is essential to elucidate the mechanisms of a range of chemical transformations. While the strength­­­­ of an acid in the gas and solution phases is conceptually well understood, how acid-base chemistry works at an interface is notoriously more complicated. Using density functional theory and nonlinear vibrational spectroscopy, we have developed a method to determine the interfacial Brønsted-Lowry acidity of aliphatic alcohols adsorbed on the {100} surface of the model perovskite, strontium titanate. Here we show that, while shorter and less branched alkanols are less acidic as a gas and more acidic in solution, shorter alcohols are less acidic whereas less substituted alkanols are more acidic at the gas-surface interface. Hydrogen bonding plays a critical role in defining acidity, whereas structure-acidity relationships are dominated by van der Waals interactions between the alcohol and the surface.

Funding

UT-ORNL JDRD program by Tennessee Science Alliance

NSF CAREER CHE-1753273

Center for Functional Nanomaterials, a U.S. DOE Office of Science Facility, and the Scientific Data and Computing Center, a component of the Computational Science Initiative at Brookhaven National Laboratory under Contract no. DE-SC0012704

U.S. DOE, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division

U.S. DOE, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division

History

Email Address of Submitting Author

sharani.roy@utk.edu

Institution

University of Tennessee, Knoxville

Country

USA

ORCID For Submitting Author

0000-0002-1020-482X

Declaration of Conflict of Interest

No conflict of interest.

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