Ab initio Study of Hydrogen Adsorption on Metal-Decorated Borophene-Graphene Bilayer

We studied the hydrogen adsorption on the surface of a covalently bonded bilayer borophene-graphene heterostructure decorated with Pt, Ni, Ag, and Cu atoms. Due to its structure, the borophene-graphene bilayer combines borophene activity with the mechanical stability of graphene. Based on the density functional theory calculations, we determined the energies and preferred adsorption sites of these metal atoms on the heterostructure’s borophene surface. Since boron atoms in different positions can have different reactivities with respect to metal atoms, we considered seven possible adsorption positions. According to our calculations, all three metals adsorb in the top position above the boron atom and demonstrate catalytic activity. Among the metals considered, copper had the best characteristics. Copper-decorated heterostructure possesses a feasible near-zero overpotential for hydrogen evolution reaction. However, the borophene-graphene bilayer decorated with copper is unstable with respect to compression. Small deformations lead to irreversible structural changes in the system. Thus, compression cannot be used as an effective mechanism for additional potential reduction.

Designing of Nanoscale Capacitor Based on Twin-graphene

‘Twin-graphene’ bilayer based nanoscale capacitor and nanoscale dielectric capacitor are designed using density functional theory approach including van der Waals dispersion correction. A strong effect on electronic properties is observed...

Molecular Dynamics of graphene bilayer: in water armchair AB 9x4y turbostratic.

Graphene forms armchair or zigzag bilayers with AA or AB lined sheets, which differ its properties. This work present a Molecular dynamics study of a graphene bilayer model developed to understand the way of its interactions in aqueous solution, including SDS and LAS surfactants. Structures of 9x and 4y aromatic rings shows a turbostratic stacking with 3,33Å between the sheets. This structure as stable in water and attract the surfactants with sp3 carbon chains, with hydrophobic interactions and carboxylic groups at the edges. It exhibits stable behavior from room temperature to 368K, with a rotational angle of 20Å between the leaves, demonstrating a turbostratic alignment. The adhered surfactants are aligned horizontally, following the movement of the bilayer. They present altered conformational freedom, with the polar portion out of the plane, near to the edges. The reproducibility of experimental intermolecular interactions with hydrophobic portions of the surfactants was also obtained, maintaining a trajectory with turbostratic angulation between the leaves. The predicted molecular behavior of graphene bilayer in aqueous solution contributes to the planning of graphene-based materials.