Water (Non-)Interaction with MoO3

Ashley R Head; Chiara Gattinoni; Lena Trotochaud; Yi Yu; Osman Karslıoğlu; Sven Pletincx; Bryan Eichhorn; Hendrik Bluhm

doi:10.1021/acs.jpcc.9b03822

Water (Non-)Interaction with MoO₃

J Phys Chem C Nanomater Interfaces. 2019 Jul 11;123(27):16836-16842. doi: 10.1021/acs.jpcc.9b03822. Epub 2019 Jun 20.

Authors

Ashley R Head¹, Chiara Gattinoni², Lena Trotochaud³, Yi Yu^{3

4}, Osman Karslıoğlu³, Sven Pletincx^{3

5}, Bryan Eichhorn⁴, Hendrik Bluhm^{3

3

6}

Affiliations

¹ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States.
² Materials Theory, Department of Materials, ETH Zürich, Wolfgang-Pauli-Str. 27, 8093 Zürich, Switzerland.
³ Chemical Sciences Division and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
⁴ Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States.
⁵ Department of Materials and Chemistry, Research Group Electrochemical and Surface Engineering (SURF), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
⁶ Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, D-14195 Berlin, Germany.

Abstract

Molybdenum(VI) oxide (MoO₃) is used in a number of technical processes such as gas filtration and heterogeneous catalysis. In these applications, the adsorption and dissociation of water on the surface can influence the chemistry of MoO₃ and thus the course of heterogeneous reactions. We use ambient pressure X-ray photoelectron spectroscopy to study the interaction of water with a stoichiometric MoO₃ surface and a MoO₃ surface that features oxygen defects and hydroxyl groups. The experimental results are supported by density functional theory calculations. We show that on a stoichiometric MoO₃(010) surface, where Mo sites are unavailable, water adsorption is strongly disfavored. However, the introduction of surface species, which can interact with the lone pairs on the water O atom, e.g., Mo⁵⁺ atoms or surface OH groups, promotes water adsorption. Dissociation of water is favored at unsaturated Mo sites, i.e., at oxygen vacancies, while water adsorbs molecularly at hydroxyl sites.