Demissie, Ephrem G. and Tang, Wai Kit and Siu, Chi-Kit (2022) Structure-Property Relationship of Oxygen-Doped Two-Dimensional Gallium Selenide for Hydrogen Evolution Reaction Revealed from Density Functional Theory. ACS Applied Energy Materials, 5 (5). pp. 6070-6079. ISSN 2574-0962, DOI https://doi.org/10.1021/acsaem.2c00472.
Full text not available from this repository.Abstract
Two-dimensional (2D) gallium selenide (GaSe) is known for its inert surface and wide bandgap, limiting its application as a photocatalytic material for the hydrogen evolution reaction (HER). Partial substitution of Se with O atoms can improve its catalytic efficiency. This work discovered that the surface activity of the substitutional O-doped single-layer GaSe surfaces (GaSe1-xOx, for x <= 22%) and their bandgap sizes are dependent on the detailed atomic configuration of the dopants, as revealed from density functional theory. For GaSe1-xOx at low O contents, where all O atoms are favorably separated by at least one-GaSe-Ga- unit, the surface activity for the HER is insignificantly improved by increasing dopant concentration. By contrast, when more O dopants are available and arranged in adjacent positions (O-Ga-O), the hydrogen adsorption efficiency of GaSe1-xOx increases and their bandgaps are reduced with increasing dopant concentration. These important features are attributed to weakening of the Ga-O covalent interaction in these more localized dopant arrangements, which in turn strengthens the O-H bonds. This weakened Ga-O covalent bond also descends the conduction band minimum toward the Fermi level, resulting in bandgap reduction and thus favoring visible-light absorption. Optimal atomic configurations (all having localized O-dopant arrangements) have been identified, and they exhibit almost thermoneutral hydrogen adsorption free energy Delta G(H) and small bandgaps (2.09-2.21 eV), making them promising materials to perform an efficient HER. Fine-tuning the Ga-O interaction by applying tensile strength T-s parallel to the 2D surface of up to 1% further reduces their bandgaps to 1.95-2.05 eV. Our theoretical predictions suggest that controlling the atomic configuration of dopants provides opportunities for engineering single-layered GaSe1-xOx materials with surface reactivity and bandgaps that suit photocatalytic water splitting.
| Item Type: | Article |
|---|---|
| Funders: | Hong Kong Research Grants Council (CityU 11301421) |
| Uncontrolled Keywords: | GaSe; water splitting; photocatalysis; hydrogen absorption; surface reactivity |
| Subjects: | Q Science > QD Chemistry |
| Divisions: | Deputy Vice Chancellor (Research & Innovation) Office > Institute of Research Management and Services |
| Depositing User: | Ms. Juhaida Abd Rahim |
| Date Deposited: | 17 Jan 2025 07:13 |
| Last Modified: | 17 Jan 2025 07:13 |
| URI: | http://eprints.um.edu.my/id/eprint/41730 |
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