Direct Imaging of Atomic Permeation Through a Vacancy Defect in the Carbon Lattice

• Published in: Angewandte Chemie International Edition Vol. 59; no. 51; pp. 22922 - 22927
• Main Authors: Cao, Kecheng, Skowron, Stephen T., Stoppiello, Craig T., Biskupek, Johannes, Khlobystov, Andrei N., Kaiser, Ute
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 14-12-2020; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Carbon; carbon nanotube; Chemical bonds; Communication; Communications; Density functional theory; Graphene; Lattice vacancies; Nanoparticles; Nanotechnology; Nanotubes; Orifices; Palladium; Penetration; permeation; selective membrane; Single wall carbon nanotubes; transmission electron microscopy; carbon nanotube; transmission electron microscopy; permeation; selective membrane; graphene
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202010630

Porous graphene has shown promise as a new generation of selective membrane for sieving atoms, ions and molecules. However, the atomistic mechanisms of permeation through defects in the graphenic lattice are still unclear and remain unobserved in action, at the atomic level. Here, the direct observation of palladium atoms from a nanoparticle passing through a defect in a single‐walled carbon nanotube one‐by‐one has been achieved with atomic resolution in real time, revealing key stages of the atomic permeation. Bonding between the moving atom and dangling bonds around the orifice, immediately before and after passing through the subnano‐pore, plays an important role in the process. Curvature of the graphenic lattice crucially defines the direction of permeation from concave to convex side due to a difference in metal‐carbon bonding at the curved surfaces as confirmed by density functional theory calculations, demonstrating the potential of porous carbon nanotubes for atom sieving.
This work reveals the mechanism of atomic permeation through a subnano‐pore in graphenic lattice by in situ aberration‐corrected high‐resolution transmission electron microscopy imaging, highlighting the importance of chemical bonding between the mobile atom and dangling bonds around the subnano‐pore. This new phenomenon and permeation mechanism are likely to play a role in the filtration processes by porous graphenic carbon based membranes.