Recently, two-dimensional, layered materials such as graphene and hexagonal boron nitride (h-BN) have been identified as interesting materials for a range of applications. Here, we demonstrate the corrosion prevention applications of h-BN in marine coatings. The performance of h-BN/polymer hybrid coatings, applied on stainless steel, were evaluated using electrochemical techniques in simulated seawater media [marine media]. h-BN/polymer coating shows an efficient corrosion protection with a low corrosion current density of 5.14 × 10(-8) A/cm(2) and corrosion rate of 1.19 × 10(-3) mm/year and it is attributed to the hydrofobic, inert and dielectric nature of boron nitride. The results indicated that the stainless steel with coatings exhibited improved corrosion resistance. Electrochemical impedance spectroscopy and potentiodynamic analysis were used to propose a mechanism for the increased corrosion resistance of h-BN coatings.
Recently, a lot of interest has been centred on the optical properties of hexagonal boron nitride (h‐BN), which has a similar lattice structure to graphene. Interestingly, h‐BN has a wide bandgap and is biocompatible, so it has potential applications in multiphoton bioimaging, if it can exhibit large nonlinear optical (NLO) properties. However, extensive investigation into the NLO properties of h‐BN have not been done so far. Here, NLO properties of 2D h‐BN nanosheets (BNNS) are reported for the first time, using 1064‐nm NIR laser radiation with a pulse duration of 10 ns using the Z‐scan technique. The reverse saturable absorption occurs in aqueous colloidal solutions of BNNS with a very large two‐photon absorption cross section (σ
2PA) of ≈57 × 10−46 cm4 s−1 photon−1. Also, by using UV–Vis absorption spectroscopy, the temperature coefficient of the bandgap (dE
g/dT) of BNNS is determined to be 5.9 meV K−1. Further defect‐induced photoluminescence emission in the UV region is obtained in the 283–303 K temperature range, under excitations of different wavelengths. The present report of large σ
2PA combined with stability and biocompatibility could open up new possibilities for the application of BNNS as a potential optical material for multiphoton bioimaging and advanced photonic devices.
Low-density nanostructured foams are often limited in applications due to their low mechanical and thermal stabilities. Here we report an approach of building the structural units of three-dimensional (3D) foams using hybrid two-dimensional (2D) atomic layers made of stacked graphene oxide layers reinforced with conformal hexagonal boron nitride (h-BN) platelets. The ultra-low density (1/400 times density of graphite) 3D porous structures are scalably synthesized using solution processing method. A layered 3D foam structure forms due to presence of h-BN and significant improvements in the mechanical properties are observed for the hybrid foam structures, over a range of temperatures, compared with pristine graphene oxide or reduced graphene oxide foams. It is found that domains of h-BN layers on the graphene oxide framework help to reinforce the 2D structural units, providing the observed improvement in mechanical integrity of the 3D foam structure.
The
development of novel efficient and robust electrocatalysts with sufficient
active sites is one of the key parameters for hydrogen evolution reactions
(HER) catalysis, which plays a key role in hydrogen production for
clean energy harvesting. Recently, two-dimensional (2D) materials,
especially those based upon transition metal dichalcogenides such
as molybdenum disulfide (MoS2), have gained attention for
the catalysis of hydrogen production because of their exceptional
properties. Innovative strategies have been developed to engineer
these material systems for improvements in their catalytic activity.
Toward this aim, the facile growth of MoS2 clusters by
sulfurization of molybdenum dioxide (MoO2) particles supported
on reduced graphene oxide (rGO) foams using the chemical vapor deposition
(CVD) method is reported. This approach created various morphologies
of MoS2 with large edges and defect densities on the basal
plane of rGO supported MoS2 structures, which are considered
as active sites for HER catalysis. In addition, MoS2 nanostructures
on the surface of the porous rGO network show robust physical interactions,
such as van der Waals and π–π interactions between
MoS2 and rGO. These features result in an improved process
to yield a suitable HER catalyst. In order to gain a better understanding
of the improvement of this MoS2-based HER catalyst, fully
atomistic molecular dynamics (MD) simulations of different defect
geometries were also performed.
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