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Water dissociation on mixed Co-Fe oxide bilayer nanoislands on Au(111)

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We investigate the hydroxylation behaviour of mixed Co-Fe oxide nanoislands synthesized on a Au(111) surface under exposure to water vapour at vacuum conditions. The pure Co and Fe bilayer oxides both become hydroxylated by water exposure in vacuum conditions, albeit to a very different extent. It is however an open question how mixed oxides, exposing sites with a mixed coordination to Fe and Co, behave. By forming surface O species with a mixed Fe/Co coordination, we can investigate the nature of such sites. By means of scanning tunnelling microscopy and x-ray photoelectron spectroscopy, we characterize a series of Co-Fe oxides samples with different Fe contents at the atomic scale and observe a scaling of the hydroxylation degree with the amount of Fe inside the Co-Fe oxides. Our results indicate that the Fe dopants within the Co-Fe oxides have opposing effects on edge and basal plane sites modifying the maximum hydroxylation degree of pure cobalt oxide, perturbing the original binding sites of H, releasing the absorbed H or blocking the diffusion pathway of H.

Original languageEnglish
Article number164004
JournalJournal of Physics Condensed Matter
Publication statusPublished - Apr 2022

Bibliographical note

Publisher Copyright:
© 2022 IOP Publishing Ltd.

    Research areas

  • Co oxide, Fe oxide, hydroxylation, mixed oxides, scanning tunnelling microscopy (STM), water exposure, x-ray photoelectron spectroscopy (XPS)

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