Water Dissociation and Hydroxyl Formation on Ni(110)



Gerrard, Nikki, Mistry, Kallum, Darling, George R and Hodgson, Andrew
(2020) Water Dissociation and Hydroxyl Formation on Ni(110). JOURNAL OF PHYSICAL CHEMISTRY C, 124 (43). pp. 23815-23822.

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Abstract

Nickel is an active catalyst for hydrogenation and re-forming reactions, with the reactions showing a strong dependence on the surface exposed. Here, we describe the mixed hydroxyl-water phases formed during water dissociation on Ni(110) using scanning tunneling microscopy and low-current low-energy electron diffraction. Water dissociation starts between 150 and 180 K as the H-bond structure evolves from linear one-dimensional (1D) chains of intact water into a two-dimensional (2D) network containing short rows of face-sharing hexagonal rings. As further water desorbs, the hexagonal rows adopt a local (2 × 3) arrangement, forming small, disordered domains separated by strain relief features. Decomposition of this phase occurs near 220 K to form linear 1D structures consisting of flat, zigzag water chains, with each water stabilized by donating one H to hydroxyl to form a branched chain structure. The OH-H<sub>2</sub>O chains repel each other, with the saturation layer ordering into a (2 0, 1 4) structure that decomposes to OH near 245 K as further water desorbs. The structure of the mixed OH/H<sub>2</sub>O phases is discussed and contrasted with those found on the related Cu(110) surface, with the differences attributed to strain in the 2D H-bond network caused by the short Ni lattice spacing and strong bond to OH/H<sub>2</sub>O.

Item Type: Article
Uncontrolled Keywords: 40 Engineering, 34 Chemical Sciences, 3406 Physical Chemistry
Depositing User: Symplectic Admin
Date Deposited: 07 Oct 2020 15:00
Last Modified: 20 Jun 2024 19:41
DOI: 10.1021/acs.jpcc.0c08708
Open Access URL: https://pubs.acs.org/doi/10.1021/acs.jpcc.0c08708
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3103689