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Title: Optically probing Al—O and O—H vibrations to characterize water adsorption and surface reconstruction on α-alumina: An experimental and theoretical study

Oxide/water interfaces are ubiquitous in a wide variety of applications and the environment. Despite this ubiquity, and attendant decades of study, gaining molecular level insight into water/oxide interaction has proven challenging. In part, this challenge springs from a lack of tools to concurrently characterize changes in surface structure (i.e., water/oxide interaction from the perspective of the solid) and O—H population and local environment (i.e., water/oxide interaction from the water perspective). Here, we demonstrate the application of surface specific vibrational spectroscopy to the characterization of the interaction of the paradigmatic α-Al{sub 2}O{sub 3}(0001) surface and water. By probing both the interfacial Al—O (surface phonon) and O—H spectral response, we characterize this interaction from both perspectives. Through electronic structure calculation, we assign the interfacial Al—O response and rationalize its changes on surface dehydroxylation and reconstruction. Because our technique is all-optical and interface specific, it is equally applicable to oxide surfaces in vacuum, ambient atmospheres and at the solid/liquid interface. Application of this approach to additional alumina surfaces and other oxides thus seems likely to significantly expand our understanding of how water meets oxide surfaces and thus the wide variety of phenomena this interaction controls.
Authors:
; ; ;  [1] ; ;  [2]
  1. Fritz Haber Institute of the Max Planck Society, 14195 Berlin (Germany)
  2. Institute of Chemistry, University of Potsdam, 14476 Potsdam OT Golm (Germany)
Publication Date:
OSTI Identifier:
22416083
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; ALUMINIUM OXIDES; ELECTRONIC STRUCTURE; GAIN; HYDROGEN; INTERFACES; LIQUIDS; OXYGEN; PHONONS; PROBES; SOLIDS; SPECTRAL RESPONSE; SURFACES; WATER