Impact of Ti Incorporation on Hydroxylation and Wetting of Fe3O4

Kelsey A. Stoerzinger, Carolyn I. Pearce, Timothy C. Droubay, Vaithiyalingam Shutthanandan, Andrey Shavorskiy, Hendrik Bluhm, Kevin M. Rosso

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Understanding the interaction of water with compositionally tuned metal oxides is central to exploiting their unique catalytic and magnetic properties. However, processes such as hydroxylation, wetting, and resulting changes in electronic structure at ambient conditions are challenging to probe in situ. Here, we examine the hydroxylation and wetting of Fe(3-x)TixO4 (001)-oriented epitaxial films directly using ambient pressure X-ray photoelectron spectroscopy under controlled relative humidity. Fe2+ formation promoted by Ti4+ substitution for Fe3+ increases with hydroxylation, commensurate with a decrease in the surface work function or change in the surface dipole. The incorporation of small amounts of Ti (x = 0.25) as a bulk dopant dramatically impacts hydroxylation, in part due to surface segregation, leading to coverages closer to that of TiO2 than Fe3O4. However, the Fe(3-x)TixO4 compositional series shows a similar affinity for water physisorption, which begins at notably lower relative humidity than on TiO2. The findings suggest that relative humidity rather than surface hydroxyl density controls wettability. Studies of this kind directly relate to rational design of doped magnetite into more active catalysts for UV/Fenton degradation, the adsorption of contaminants, and the development of spin filters.

Original languageEnglish (US)
Pages (from-to)19288-19295
Number of pages8
JournalJournal of Physical Chemistry C
Issue number35
StatePublished - Sep 7 2017
Externally publishedYes

Bibliographical note

Funding Information:
This work is based on research sponsored by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences and Biosciences (CSGB), through its Geosciences program at Pacific Northwest National Laboratory (PNNL). K.A.S. gratefully acknowledges the Linus Pauling Distinguished Post-Doctoral Fellowship support from PNNL (PNNL LDRD 69319). The ALS and the MES beamline 11.0.2 is supported by the Director, Office of Science, BES-CSGB and the Materials Sciences Division at the Lawrence Berkeley National Laboratory under contract DE-AC02-05CH11231. A portion of this research was performed using EMSL, a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at PNNL. PNNL is a multiprogram national laboratory operated for DOE by Battelle.

Publisher Copyright:
© 2017 American Chemical Society.


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