Graphene, phosphorene and silicene coatings on the (0001) surfaces of hcp metals: Structural stability and hydrophobicity

• Single atomic layer or monolayer (ML) 2D materials have unique features that can be relevant for protection and functionalization of high-performance surfaces. Here we report a combined density functional theory and ab initio molecular dynamics study on the stability of graphene (Gr), phosphorene (Pp) and silicene (Sl) coatings at the most stable (0001) surface of the metals that have hcp structure at room temperature: Hf, Mg, Os, Re, Ru, Sc, Ti, Zn and Zr. We found that the three 2D materials are stable at the surfaces of many of these metals: Gr is stable at Os, Re, Ti, Zn and Zr; Pp is stable in the blue form at Hf, Mg, Ti and Zr; Sl is stable in the 2D zigzag structure at Hf, Mg and Ti and in the planar form at the Zr surface. For the remaining metals Gr, Pp and Sl do not form van der Waals bonded MLs. In those cases we found structures such as 2D arrangements of mixed hexagons and pentagons, trigonal pyramidal structures and 2 half-monolayers. Many of these structures are very stable coatings covalently bound to the surfaces with considerable adsorption energies that can reach − 2 eV per atom of the coating. Gr imparts hydrophobicity to the surfaces of all materials here studied and increases the distance between these and the first H2O layer by as much as 75 % for Gr coated Ti. These H2O layers have increased rigidity despite being located further apart from the surfaces. These effects could be explored for the protection or functionalization of high-performance systems such as metallic electrodes for example.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

Nyckelord

2D materials

Graphene

Phosphorene

Silicene

Hcp metals

Hf

Mg

Os

Re

Ru

Sc

Ti

Zn and Zr

Hydrophobic

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