8 research outputs found
Structural and Thermal Stability of Graphyne and Graphdiyne Nanoscroll Structures
Graphynes and graphdiynes are generic
names for families of two-dimensional
carbon allotropes, where acetylenic groups connect benzenoid-like
hexagonal rings, with the coexistence of sp and sp<sup>2</sup> hybridized
carbon atoms. The main differences between graphynes and graphdiynes
are the number of acetylenic groups (one and two for graphynes and
graphdiynes, respectively). Similarly to graphene nanoscrolls, graphyne
and graphdiynes nanoscrolls are nanosized membranes rolled into papyrus-like
structures. In this work we studied through molecular dynamics simulations,
using reactive potentials, the structural and thermal (up to 1000
K) stability of α,β,γ-graphyne and α,β,γ-graphdiyne
scrolls. Our results demonstrate that stable nanoscrolls can be created
for all the structures studied here, although they are less stable
than corresponding graphene scrolls. This can be elucidated as a result
of the higher graphyne/graphdiyne structural porosity in relation
to graphene, and as a consequence, the π–π stacking
interactions decrease
Structural and Thermal Stability of Graphyne and Graphdiyne Nanoscroll Structures
Graphynes and graphdiynes are generic
names for families of two-dimensional
carbon allotropes, where acetylenic groups connect benzenoid-like
hexagonal rings, with the coexistence of sp and sp<sup>2</sup> hybridized
carbon atoms. The main differences between graphynes and graphdiynes
are the number of acetylenic groups (one and two for graphynes and
graphdiynes, respectively). Similarly to graphene nanoscrolls, graphyne
and graphdiynes nanoscrolls are nanosized membranes rolled into papyrus-like
structures. In this work we studied through molecular dynamics simulations,
using reactive potentials, the structural and thermal (up to 1000
K) stability of α,β,γ-graphyne and α,β,γ-graphdiyne
scrolls. Our results demonstrate that stable nanoscrolls can be created
for all the structures studied here, although they are less stable
than corresponding graphene scrolls. This can be elucidated as a result
of the higher graphyne/graphdiyne structural porosity in relation
to graphene, and as a consequence, the π–π stacking
interactions decrease
Structural and Thermal Stability of Graphyne and Graphdiyne Nanoscroll Structures
Graphynes and graphdiynes are generic
names for families of two-dimensional
carbon allotropes, where acetylenic groups connect benzenoid-like
hexagonal rings, with the coexistence of sp and sp<sup>2</sup> hybridized
carbon atoms. The main differences between graphynes and graphdiynes
are the number of acetylenic groups (one and two for graphynes and
graphdiynes, respectively). Similarly to graphene nanoscrolls, graphyne
and graphdiynes nanoscrolls are nanosized membranes rolled into papyrus-like
structures. In this work we studied through molecular dynamics simulations,
using reactive potentials, the structural and thermal (up to 1000
K) stability of α,β,γ-graphyne and α,β,γ-graphdiyne
scrolls. Our results demonstrate that stable nanoscrolls can be created
for all the structures studied here, although they are less stable
than corresponding graphene scrolls. This can be elucidated as a result
of the higher graphyne/graphdiyne structural porosity in relation
to graphene, and as a consequence, the π–π stacking
interactions decrease
Structural and Thermal Stability of Graphyne and Graphdiyne Nanoscroll Structures
Graphynes and graphdiynes are generic
names for families of two-dimensional
carbon allotropes, where acetylenic groups connect benzenoid-like
hexagonal rings, with the coexistence of sp and sp<sup>2</sup> hybridized
carbon atoms. The main differences between graphynes and graphdiynes
are the number of acetylenic groups (one and two for graphynes and
graphdiynes, respectively). Similarly to graphene nanoscrolls, graphyne
and graphdiynes nanoscrolls are nanosized membranes rolled into papyrus-like
structures. In this work we studied through molecular dynamics simulations,
using reactive potentials, the structural and thermal (up to 1000
K) stability of α,β,γ-graphyne and α,β,γ-graphdiyne
scrolls. Our results demonstrate that stable nanoscrolls can be created
for all the structures studied here, although they are less stable
than corresponding graphene scrolls. This can be elucidated as a result
of the higher graphyne/graphdiyne structural porosity in relation
to graphene, and as a consequence, the π–π stacking
interactions decrease
Structural and Thermal Stability of Graphyne and Graphdiyne Nanoscroll Structures
Graphynes and graphdiynes are generic
names for families of two-dimensional
carbon allotropes, where acetylenic groups connect benzenoid-like
hexagonal rings, with the coexistence of sp and sp<sup>2</sup> hybridized
carbon atoms. The main differences between graphynes and graphdiynes
are the number of acetylenic groups (one and two for graphynes and
graphdiynes, respectively). Similarly to graphene nanoscrolls, graphyne
and graphdiynes nanoscrolls are nanosized membranes rolled into papyrus-like
structures. In this work we studied through molecular dynamics simulations,
using reactive potentials, the structural and thermal (up to 1000
K) stability of α,β,γ-graphyne and α,β,γ-graphdiyne
scrolls. Our results demonstrate that stable nanoscrolls can be created
for all the structures studied here, although they are less stable
than corresponding graphene scrolls. This can be elucidated as a result
of the higher graphyne/graphdiyne structural porosity in relation
to graphene, and as a consequence, the π–π stacking
interactions decrease
Thermoelectricity Enhanced Electrocatalysis
We
show that thermoelectric materials can function as electrocatalysts
and use thermoelectric voltage generated to initiate and boost electrocatalytic
reactions. The electrocatalytic activity is promoted by the use of
nanostructured thermoelectric materials in a hydrogen evolution reaction
(HER) by the thermoelectricity generated from induced temperature
gradients. This phenomenon is demonstrated using two-dimensional layered
thermoelectric materials Sb<sub>2</sub>Te<sub>3</sub> and Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> where a current density approaching
∼50 mA/cm<sup>2</sup> is produced at zero potential for Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> in the presence of a temperature
gradient of 90 °C. In addition, the turnover frequency reaches
to 2.7 s<sup>–1</sup> at 100 mV under this condition which
was zero in the absence of temperature gradient. This result adds
a new dimension to the properties of thermoelectric materials which
has not been explored before and can be applied in the field of electrocatalysis
and energy generation
Lightweight Hexagonal Boron Nitride Foam for CO<sub>2</sub> Absorption
Weak van der Waals forces between
inert hexagonal boron nitride (h-BN) nanosheets make it easy for them
to slide over each other, resulting in an unstable structure in macroscopic
dimensions. Creating interconnections between these inert nanosheets
can remarkably enhance their mechanical properties. However, controlled
design of such interconnections remains a fundamental problem for
many applications of h-BN foams. In this work, a scalable <i>in situ</i> freeze-drying synthesis of low-density, lightweight
3D macroscopic structures made of h-BN nanosheets chemically connected
by poly(vinyl alcohol) (PVA) molecules <i>via</i> chemical
cross-link is demonstrated. Unlike pristine h-BN foam which disintegrates
upon handling after freeze-drying, h-BN/PVA foams exhibit stable mechanical
integrity in addition to high porosity and large surface area. Fully
atomistic simulations are used to understand the interactions between
h-BN nanosheets and PVA molecules. In addition, the h-BN/PVA foam
is investigated as a possible CO<sub>2</sub> absorption and as laser
irradiation protection material
Hybrid MoS<sub>2</sub>/h-BN Nanofillers As Synergic Heat Dissipation and Reinforcement Additives in Epoxy Nanocomposites
Two-dimensional
(2D) nanomaterials as molybdenum disulfide (MoS<sub>2</sub>), hexagonal
boron nitride (h-BN), and their hybrid (MoS<sub>2</sub>/h-BN) were
employed as fillers to improve the physical properties of epoxy composites.
Nanocomposites were produced in different concentrations and studied
in their microstructure, mechanical and thermal properties. The hybrid
2D mixture imparted efficient reinforcement to the epoxy leading to
increases of up to 95% in tensile strength, 60% in ultimate strain,
and 58% in Young’s modulus. Moreover, an enhancement of 203%
in thermal conductivity was achieved for the hybrid composite as compared
to the pure polymer. The incorporation of MoS<sub>2</sub>/h-BN mixture
nanofillers in epoxy resulted in nanocomposites with multifunctional
characteristics for applications that require high mechanical and
thermal performance