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Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors
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Transient Response of h-BN-Encapsulated Graphene Transistors: Signatures of Self-Heating and Hot-Carrier Trapping
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Lab-in-a-Shell: Encapsulating Metal Clusters for Size Sieving Catalysis
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Dynamic, Polymer-Integrated Crystals for Efficient, Reversible Protein Encapsulation
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A Segregated, Partially Oxidized, and Compact Ag 10 Cluster within an Encapsulating DNA Host
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Azobenzene-Bridged Expanded “Texas-sized” Box: A Multi-Responsive Receptor for Aryl Dianion Encapsulation
We report an expanded "Texas-sized" molecular box (AzoTxSB) that incorporates photo-responsive azobenzene bridging subunits and anion recognition motifs. The shape of this box can be switched through light induced E<–>Z photoisomerization of the constituent azobenzenes. This allows various anionic substrates to be bound and released by using other environmental stimuli, such as pH and anion competition.
Unconventional Route to Encapsulated Ultrasmall Gold Nanoparticles for High-Temperature Catalysis
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In Situ Formation of Carbon Nanotubes Encapsulated within Boron Nitride Nanotubes via Electron Irradiation
We report experimental evidence of the formation by in situ electron-irradiation of single-walled carbon nanotubes (C NT) confined within boron nitride nanotubes (BN-NT). The electron radiation stemming from the microscope supplies the energy required by the amorphous carbonaceous structures to crystallize in a tubular form in a catalyst free procedure, at room temperature and high vacuum. The structural defects resulting from the interaction of the shapeless carbon with the BN nanotube are corrected in a self-healing process throughout the crystallinization. Structural changes developed during the irradiation process such as defects formation and evolution, shrinkage, and shortness of the BN-NT were in situ monitored. The outer BN wall provides a protective and insulating shell against environmental Perturbations to the inner C-NT without affecting their electronic properties, as demonstrated by first principles calculations.
Identification of carbon-encapsulated iron nanoparticles as active species in non-precious metal oxygen reduction catalysts
The widespread use of fuel cells is currently limited by the lack of efficient and cost-effective catalysts for the oxygen reduction reaction. Iron-based non-precious metal catalysts exhibit promising activity and stability, as an alternative to state-of-the-art platinum catalysts. However, the identity of the active species in non-precious metal catalysts remains elusive, impeding the development of new catalysts. Here we demonstrate the reversible deactivation and reactivation of an iron-based non-precious metal oxygen reduction catalyst achieved using high-temperature gas-phase chlorine and hydrogen treatments. In addition, we observe a decrease in catalyst heterogeneity following treatment with chlorine and hydrogen, using Mössbauer and X-ray absorption spectroscopy. Our study reveals that protected sites adjacent to iron nanoparticles are responsible for the observed activity and stability of the catalyst. These findings may allow for the design and synthesis of enhanced non-precious metal oxygen reduction catalysts with a higher density of active sites.
Encapsulation kinetics and dynamics of carbon monoxide in clathrate hydrate
Carbon monoxide clathrate hydrate is a potentially important constituent in the solar system. In contrast to the well-established relation between the size of gaseous molecule and hydrate structure, previous work showed that carbon monoxide molecules preferentially form structure-I rather than structure-II gas hydrate. Resolving this discrepancy is fundamentally important to understanding clathrate formation, structure stabilization and the role the dipole moment/molecular polarizability plays in these processes. Here we report the synthesis of structure-II carbon monoxide hydrate under moderate high-pressure/low-temperature conditions. We demonstrate that the relative stability between structure-I and structure-II hydrates is primarily determined by kinetically controlled cage filling and associated binding energies. Within hexakaidecahedral cage, molecular dynamic simulations of density distributions reveal eight low-energy wells forming a cubic geometry in favour of the occupancy of carbon monoxide molecules, suggesting that the carbon monoxide–water and carbon monoxide–carbon monoxide interactions with adjacent cages provide a significant source of stability for the structure-II clathrate framework.