Enhancing α-Fe2O3(0 0 0 1) surfaces reactivity through lattice-strain control

• Published in: Applied surface science Vol. 534; p. 147605
• Main Authors: Mahmoud, Agnes, Dupont, Céline
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.12.2020; Elsevier
• Subjects: Chemical Sciences; Density functional theory; Hematite; Strain; Water adsorption; Hematite; Water adsorption; Density functional theory; Strain; strain; hematite; water adsorption; density functional theory
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.147605

[Display omitted] •Strain-engineering reactivity of hematite modeled by density functional theory.•For −3% of strain, O3 and Fe-terminations compete for water adsorption.•Compression favors water adsorption on the Fe-termination, contrary to the O3 one.•Dissociation is widely favored on O3 termination by tensile strain. In-plane strain-engineered water adsorption on Fe- and O3-terminated α-Fe2O3(0 0 0 1) surfaces was investigated using dispersion corrected density functional theory. We found that in order to enhance the water adsorption capacity different type of in-plane strain is needed to be applied on the two surfaces. On Fe-terminated surface increasing compressive strain facilitates water molecular adsorption. We demonstrate that this result mainly comes from the structural behavior of the outmost Fe cation on clean Fe-terminated surface. On the contrary, in-plane tensile strain favors water adsorption and dissociation on the O3-terminated surface. We discuss in details the possible reasons of this difference between the two surfaces in terms of structural parameters. Furthermore, we found that the two surfaces can represent two competitive molecular adsorption sites at a certain tensile strain in mixed surfaces. Finally, while strain is found to have a wide influence on the dissociation of water on the O3 termination, its effect is less pronounced on the Fe terminated one. According to our results strain-engineering on hematite surfaces represents a feasible way to enhance the reactivity.