An all-purpose building block: B12N12 fullerene

First-Principles Study of B16N16 Cluster-Assembled Porous Nanomaterials

Owing to the similar valence electron structures between the B-N bond and the C-C bond, boron nitride, similar to carbon, can form abundant polymorphs with different frameworks, which possess rich mechanical and electronic properties. Using the hollow, cage-like B₁₆N₁₆ cluster as building blocks, here, we established three new BN polymorphs with low-density porous structures, termed Cub-B₁₆N₁₆, Tet-B₁₆N₁₆, and Ort-B₁₆N₁₆, which have cubic (P4¯3m), tetragonal (P4/nbm), and orthomorphic (Imma) symmetries, respectively. Our density functional theory (DFT) calculations indicated that the existence of porous structure Cub-B₁₆N₁₆, Tet-B₁₆N₁₆, and Ort-B₁₆N₁₆ were not only energetically, dynamically, thermally and mechanically stable, they were even more stable than some known phases, such as sc-B₁₂N₁₂ and Hp-BN. The obtained Pugh's ratio showed that the Cub-B₁₆N₁₆ and Tet-B₁₆N₁₆ structures were brittle materials, but Ort-B₁₆N₁₆ was ductile. The analysis of ideal strength, Young's moduli, and shear moduli revealed that the proposed new phases all exhibited sizable mechanical anisotropy. Additionally, the calculation of electronic band structures and density of states showed that they were all semiconducting with a wide, indirect band gap (~3 eV). The results obtained in this work not only identified three stable BN polymorphs, they also highlighted a bottom-up way to obtain the desired materials with the clusters serving as building blocks.

Unraveling the electronic influence and nature of covalent bonding of aryl and alkyl radicals on the B12N12 nanocage cluster

Carbon nanocage structures such as fullerene, nanotubes, nanocapsules, nanopolyhedra, cones, cubes, and onions have been reported since the discovery of C60, and they offer tremendous promise for investigating materials of low dimensions in an isolated environment. Boron Nitride (BN) nanomaterials such a: nanotubes, nanocapsules, nanoparticles, and clusters have been described in several studies and are predicted to be useful as electronic devices, high heat-resistance semiconductors, nanocables, insulator lubricants, and gas storage materials. The interaction, and electronic of octahedral B₁₂N₁₂ nanocage cluster covalently modified from the attachment of alkyl and aryl radicals were analyzed using Density Functional Theory calculations. The work discusses for the first time to our knowledge the complete investigation of the impact of the grafted aryl and alkyl groups on the electronic, bang gap, and density of states on the B₁₂N₁₂. Furthermore, this is the first complete description of these radicals attaching to a surface of B₁₂N₁₂ nanocage cluster.

Boron-Doped C24 Fullerenes for Alkyl Functionalization or Potential Polymerization

Replacing a single carbon atom in C₂₄ with a boron atom allows the functionalization of one additional carbon atom. Such a process involves little energy cost with regard to the structure of the fullerene. Two such replacements are required if the fullerenes are to act as "pearls on a string". This work shows trends for increasingly higher levels of carbon replacement with boron as well as hydrogenation, methylation, and ethylation of a subsequent carbon atom in such a boron-doped small fullerene. Additionally, dimers are shown to be stable, and the linking ethyl groups actually stabilize the overall structure more than when the ethyl groups are on the surface of the structure and are not serving as linkers. Such stringed fullerenes would certainly have applications to materials science if polymers could be made from these stringed pearls and would be suitable for neutron radiation shielding in spacecraft or spacesuits.

Be12O12 Nano-cage as a Promising Catalyst for CO2 Hydrogenation

An efficient conversion of CO₂ into valuable fuels and chemicals has been hotly pursued recently. Here, for the first time, we have explored a series of M₁₂x₁₂ nano-cages (M = B, Al, Be, Mg; X = N, P, O) for catalysis of CO₂ to HCOOH. Two steps are identified in the hydrogenation process, namely, H₂ activation to 2H*, and then 2H* transfer to CO₂ forming HCOOH, where the barriers of two H* transfer are lower than that of the H₂ activation reaction. Among the studied cages, Be₁₂O₁₂ is found to have the lowest barrier in the whole reaction process, showing two kinds of reaction mechanisms for 2H* (simultaneous transfer and a step-wise transfer with a quite low barrier). Moreover, the H₂ activation energy barrier can be further reduced by introducing Al, Ga, Li, and Na to B₁₂N₁₂ cage. This study would provide some new ideas for the design of efficient cluster catalysts for CO₂ reduction.

The cluster-assembled nanowires based on M12N12 (M = Al and Ga) clusters as potential gas sensors for CO, NO, and NO2 detection

Stable nanowires can be produced via the coalescence of M₁₂N₁₂ fullerene-like clusters and serve as promising gas sensors for CO, NO, and NO₂ detection.