Resumos
2D diamond-like functionalized nanosheets for hydrogen evolution reaction
Bruno Ipaves e Pedro Alves da Silva Autreto
Resumo:
Two-dimensional (2D) materials have been widely investigated since the discovery of
graphene in 2004 and are excellent candidates for energy storage and catalytic conversion
applications. The physical properties of 2D materials can vary considerably depending on the
synthesis and functionalization methods, where the origin of all these different properties is
still an open question. Accordingly, it is essential to investigate and understand the properties
of functionalized 2D structures. In this context, we explored the structural, thermodynamic,
dynamic, elastic and electronic properties of diamond-like graphene and diamond-like
silicene nanosheets functionalized with distinct types of atoms [1, 2]. We predicted
nanosheets with interesting physical properties and potential applications in several fields,
including van der Waals heterostructures and thermoelectric devices. In particular, we studied
and demonstrated the diamond-like silicene nanosheet functionalized with aluminum atoms
is a promising candidate for alkali metal ion batteries, mainly for sodium and potassium ion
batteries [3]. Finally, our current results have shown potential for using them as an efficient
hydrogen evolution reaction.
Anisotropic Hydrogenation Pattern in a new 2D Carbon Allotrope
Caique Campos de Oliveira, Matheus Rodrigues de Amorim Medina, Douglas Soares
Galvão e Pedro Alves da Silva Autreto
Resumo:
The discovery of graphene has renewed interest in 2D carbon nanostructures. Specifically,
researchers have proposed new structures by combining hexagonal and other polygonal
carbon rings. Recently, Bhattacharya and Jana introduced a new 2D carbon allotrope called
Tetra-Penta-Deca-Hexagonal graphene (TPDH-Gr), composed of rings with 4, 5, 10, and 6
carbon atoms [1]. This unique topology results in distinct mechanical, electronic, and optical
properties, including potential applications in UV protection. As with other 2D carbon
allotropes, TPDH-Gr”s physical and chemical properties can be modified through chemical
functionalization. However, the hydrogenation dynamics of TPDH-Gr have yet to be
explored, even though hydrogenation is a typical method for functionalization typically
occurring in experimental synthesis. In this work, we investigated the hydrogenation
dynamics of TPDH-Gr and its effects on the electronic structure using DFT and fully
atomistic reactive Molecular Dynamics simulations. This methodology has been successfully
used in previous research [2]. Our findings indicate that H atoms are mainly incorporated
on tetragonal ring sites, resulting in well-defined pentagonal carbon stripes. The
hydrogenated structures show narrow band gaps and the presence of Dirac cones,
indicating anisotropic transport properties
TPDH Nanotube: structural, mechanical and electronic properties.
Autores: Juan Rafael Gomez Quispe e Pedro Alves da Silva Autreto
Resumo:
Carbon nanotubes (CNTs) are highly sought after due to their unique mechanical, optical
and electronic properties. They can be visualized as cylindrical tubes formed by rolling twodimensional sheets of graphene, where the electronic properties of the tubes are dependent
on their chirality and diameter. Although graphene is the most used structural base, it is
theoretically possible to create NTs using other 2D carbon allotropes [1]. Some of the most
widely studied allotropes are Graphenylene, Penta-graphene, HOP-graphene, TPDHgraphene, and others, which consist of networks of linear chain polygons ranging from
tetragons to dodecagons [1]. TPDH-graphene, one of the last carbon allotrope, is composed
of sp2 carbon rings with 4, 5, 12, and 6 atoms. It exhibits both thermal and dynamic
stability, anisotropic elastic properties, and metallic behavior that can be altered by
hydrogenation of the tetragonal rings [2,3]. In this work, we explore the structure,
mechanical, and electronic properties of TPDH-NTs with chirality (n,0),(n,1), (n,n) for n 4,
using density functional theory (DFT) and molecular dynamics (MD) calculations. Our
preliminare results indicate that TPDH-NT (2,1) exhibits semiconductor behavior with a
small indirect band gap, while other TPDH-NTs show metallic behavior. We observe the
structural stability of TPDH-NT via MD at (T=300K), and the stress-strain profiles calculated
by DFT and MD show a good correlation, coinciding at the fracture limit of the TPDH-NTs.
These preliminary results suggest that TPDH-NTs possess distinct mechanical and
electronic properties compared to TPDH-2D, especially TPDH-NT with chirality (2,1), which
exhibits semiconductor behavior.