A metallic peanut-shaped carbon nanotube and its potential for CO₂ capture

One of the greatest challenges in greenhouse gas reduction is to develop low-cost materials capable of efficient CO₂ capture. Carbon, due to its flexible bonding characteristics, numerous allotropic forms, and lightweight, is an attractive material for such investigation. Inspired by the experimental synthesis of C₅₀Cl₁₀ in milligram quantities and recent works on peanut-shaped carbon nanotubes (PSNT), using state-of-the-art first-principles theory and molecular dynamics simulation, we have discovered a new form of C₅₀ fullerene-based PSNT, α-PSNT. which is not only dynamically and thermally stable, but also energetically more stable than previously identified PSNTs composed of C₅₀ cages, and can withstand temperatures to 1000 K. Due to its unique atomic configuration, α-PSNT exhibits interesting physical properties including a high heat capacity, ultra-soft mechanical property with Young's modulus being a quarter of single-walled carbon nanotube (SWNT), and chirality independent metallicity. A systematical study of the adsorption properties reveals that both pristine and N-doped α-PSNTs have better CO₂ adsorption properties than SWNTs. The underline mechanism is that the intrinsic metallicity improves its ability to capture CO₂ as well as other gases because of the high density of electronic states at the Fermi level.