Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

DFT + U study of the adsorption and dissociation of water on clean, defective, and oxygen-covered U3Si2{001}, {110}, and {111} surfaces

Jossou, Ericmoore, Malakkal, Linu, Dzade, Nelson, Claisse, Antoine, Szpunar, Barbara and Szpunar, Jerzy 2019. DFT + U study of the adsorption and dissociation of water on clean, defective, and oxygen-covered U3Si2{001}, {110}, and {111} surfaces. Journal of Physical Chemistry C 123 (32) , pp. 19453-19467. 10.1021/acs.jpcc.9b03076

[img]
Preview
PDF - Published Version
Available under License Creative Commons Attribution.

Download (3MB) | Preview

Abstract

The interfacial interaction of U3Si2 with water leads to corrosion of nuclear fuels, which affects various processes in the nuclear fuel cycle. However, the mechanism and molecular-level insights into the early oxidation process of U3Si2 surfaces in the presence of water and oxygen are not fully understood. In this work, we present Hubbard-corrected density functional theory (DFT + U) calculations of the adsorption behavior of water on the low Miller indices of the pristine and defective surfaces as well as water dissociation and accompanied H2 formation mechanisms. The adsorption strength decreases in the order U3Si2{001} > U3Si2{110} > U3Si2{111} for both molecular and dissociative H2O adsorption. Consistent with the superior reactivity, dissociative water adsorption is most stable. We also explored the adsorption of H2O on the oxygen-covered U3Si2 surface and showed that the preadsorbed oxygen could activate the OH bond and speed up the dissociation of H2O. Generally, we found that during adsorption on the oxygen-covered, defective surface, multiple water molecules are thermodynamically more stable on the surface than the water monomer on the pristine surface. Mixed molecular and dissociative water adsorption modes are also noted to be stable on the {111} surface, whereas fully dissociative water adsorption is most stable on the {110} and {001} surfaces.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Chemistry
Advanced Research Computing @ Cardiff (ARCCA)
Publisher: American Chemical Society
ISSN: 1932-7447
Funders: EPSRC
Date of First Compliant Deposit: 7 August 2019
Date of Acceptance: 11 July 2019
Last Modified: 25 Mar 2020 16:45
URI: http://orca.cf.ac.uk/id/eprint/124760

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics