Atomic structure, chemical composition, and oxidation behavior of the (001) surface of ${\text{Ni}}_2{\text{In}}_3$ intermetallic catalyst

Alfahad, Ahowd Youssef, Singh, Vipin Kumar ORCID: 0000-0002-2066-2218, Gaudry, Emilie, Ledieu, Julian ORCID: 0000-0002-9896-0426, Fournée, Vincent, Gille, Peter, Gardner, Adrian M ORCID: 0000-0002-2423-8799, Chalker, Paul R ORCID: 0000-0002-2295-6332, McGrath, Ronan ORCID: 0000-0002-9880-5741 and Sharma, Hem Raj ORCID: 0000-0003-0456-6258 (2025) Atomic structure, chemical composition, and oxidation behavior of the (001) surface of ${\text{Ni}}_2{\text{In}}_3$ intermetallic catalyst Physical Review Materials, 9 (3). 035801-. ISSN 2476-0455, 2475-9953

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Abstract

Intermetallic compounds have shown promising catalytic properties, exhibiting better selectivity and thermal stability than their metallic counterparts. Understanding their surface properties is crucial for optimizing catalytic performance. Here, we present an investigation of the atomic structure, chemical composition, and oxidation behavior of the previously unexplored binary intermetallic catalyst, ${\mathrm{Ni}}_2{\mathrm{In}}_3$, using various complementary techniques, including low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy (XPS), and low-energy ion scattering (LEIS), which provides elemental information from the topmost surface layer. We also calculated the surface energy of several possible bulk-terminated surfaces by density functional theory (DFT) to investigate surface stability. The ${\mathrm{Ni}}_2{\mathrm{In}}_3$(100) surface was prepared by ion bombardment and annealing under ultrahigh vacuum conditions. We find that ion bombardment preferentially removes indium (In), while annealing promotes In segregation to the surface. After annealing, the surface exhibits a $(1\times 1)$ LEED pattern. The surface develops a three-domain $\mathrm{c}(2\sqrt{3}\times 4)$ rectangular structure upon exposure to ambient hydrogen present in the experimental chamber or hydrogen dosed from an external source, as evidenced by both STM and LEED. Both nickel (Ni) and In oxidize upon exposure to molecular oxygen. Based on STM and LEIS results along with surface energy calculations, we reveal that the surface planes contain In atoms bonded with Ni, the catalytically active constituent, suggesting that the surface may be stabilized by intermetallic bonding.

Item Type:	Article
Uncontrolled Keywords:	40 Engineering, 4016 Materials Engineering
Divisions:	Faculty of Science & Engineering Faculty of Science & Engineering > School of Engineering Faculty of Science & Engineering > School of Physical Sciences Faculty of Science & Engineering > School of Physical Sciences > Physics Faculty of Science & Engineering > School of Engineering > Materials, Design and Manufacturing Eng
Depositing User:	Symplectic Admin
Date Deposited:	10 Dec 2025 10:38
Last Modified:	10 Dec 2025 10:38
DOI:	10.1103/physrevmaterials.9.035801
Related Websites:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3196045
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