Water Adsorption and Dissociation on Polycrystalline Copper Oxides: Effects of Environmental Contamination and Experimental Protocol

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DOI

  • Lena Trotochaud, Lawrence Berkeley Natl Lab, Lawrence Berkeley National Laboratory, United States Department of Energy (DOE), Div Chem Sci
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  • Ashley R. Head, Lawrence Berkeley Natl Lab, Lawrence Berkeley National Laboratory, United States Department of Energy (DOE), Div Chem Sci
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  • Sven Pletincx, Vrije Univ Brussel, Vrije Universiteit Brussel, Dept Mat & Chem, SURF Res Grp
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  • Osman Karslioglu, Lawrence Berkeley Natl Lab, Lawrence Berkeley National Laboratory, United States Department of Energy (DOE), Div Chem Sci
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  • Yi Yu, Univ Maryland, University of Maryland College Park, University System of Maryland, Dept Chem & Biochem
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  • Astrid Waldner, Paul Scherrer Inst, Paul Scherrer Institute, Lab Environm Chem
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  • Line Kyhl
  • Tom Hauffman, Vrije Univ Brussel, Vrije Universiteit Brussel, Dept Mat & Chem, SURF Res Grp
  • ,
  • Herman Terryn, Vrije Univ Brussel, Vrije Universiteit Brussel, Dept Mat & Chem, SURF Res Grp
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  • Bryan Eichhorn, Univ Maryland, University of Maryland College Park, University System of Maryland, Dept Chem & Biochem
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  • Hendrik Bluhm, Lawrence Berkeley Natl Lab, Lawrence Berkeley National Laboratory, United States Department of Energy (DOE), Adv Light Source

We use ambient-pressure X-ray photoelectron spectroscopy (APXPS) to study chemical changes, including hydroxylation and water adsorption, at copper oxide surfaces from ultrahigh vacuum to ambient relative humidities of similar to 5%. Polycrystalline CuO and Cu2O surfaces were prepared by selective oxidation of metallic copper foils. For both oxides, hydroxylation occurs readily, even at high-vacuum conditions. Hydroxylation on both oxides plateaus near similar to 0.01% relative humidity (RH) at a coverage of similar to 1 monolayer. In contrast to previous studies, neither oxide shows significant accumulation of molecular water; rather, both surfaces show a high affinity for adventitious carbon contaminants. Results of isobaric and isothermic experiments are compared, and the strengths and potential drawbacks of each method are discussed. We also provide critical evaluations of the effects of the hot filament of the ion pressure gauge on the reactivity of gas-phase species, the peak fitting procedure on the quantitative analysis of spectra, and rigorous accounting of carbon contamination on data analysis and interpretation. This work underscores the importance of considering experimental design and data analysis protocols during APXPS experiments with water vapor in order to minimize misinterpretations arising from these factors.

Original languageEnglish
JournalJournal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical
Volume122
Issue2
Pages (from-to)1000-1008
Number of pages9
ISSN1520-6106
DOIs
Publication statusPublished - 18 Jan 2018

    Research areas

  • RAY PHOTOELECTRON-SPECTROSCOPY, NEAR-AMBIENT CONDITIONS, MGO(100) SURFACE, REACTIVITY, PRESSURE, HYDROXYLATION, FILMS, MICROSCOPY, GROWTH, SITES

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