Reactivity of carbon6/24/2023 ![]() ![]() Our next steps include implementing catalysts and more complex molecules into carbon nanotubes, Kaiser confirms. Going forward, there are a number of innovations that might be developed and applied to the current experimental design for example, catalysts other than rhenium, carbon sources other than the fullerene cage wall, nanotubes produced or grown using an alternative method, nanotubes using different fullerene, or variations in the e-beam. In order to provide a comprehensive description of a possible mechanism for nanoprotrusion formation on carbon nanotube walls," adds Bichoutskaia, we used a multi-scale modeling approach that combined accurate quantum chemical methods with semi-empirical molecular dynamics simulations. To accomplish this we developed the real-time imaging and data acquisition technology to reveal carbon nanotubes and their interior in high contrast and atomic resolution. Kaiser comments that Our aim is use low voltage TEM which is now possible after the introduction of hardware aberration correction by Harald Rose, Max Haider and Knut Urban to study in detail the atom-by-atom level influence of electron-beam interacting with low-Z matter, which is matter with a low atomic number. They have succeeded at imaging the delicate molecules with atomic resolution and, most importantly, at capturing them in action i.e., in chemical processes within the carbon nanotube in real time. The second challenge, he continues, was solved by the researchers in Ulm, who applied a specially designed electron microscope that utilizes low energy electrons for imaging molecules and atoms. It appears that such modified fullerenes are excellent vehicles for delivery of metal atoms into nanotubes, as they enter in nanotube spontaneously and irreversibly. We tagged each fullerene with a single atom of rhenium metal, so that each molecule brings a catalytically active metal atom into the nanotube, Khlobystov explains. The fullerenes are known to be attracted strongly into the nanotube cavity by van der Waals forces. To address these challenges, the team exploited the remarkable affinity of carbon nanotube with fullerenes carbon nanostructures, which look like nanometer-sized cages and can be considered as structurally related to nanotubes. The second major challenge, he adds, was to study the delicate molecules, reactive atoms and their chemical transformation inside nanotubes in real-time at the atomic level. The presence of such metal atoms within the nanotube is important not just for investigating the chemical reactivity of the inner sidewall, but also for creating new nanostructures from the nanotube, notes Khlobystov. The main experimental challenge the team faced was to devise a method for delivering single atoms of catalytically active metal into very narrow carbon nanotubes with a diameter of 1.5 nm about 80,000 times smaller than the thickness of human hair. Meyer and Jens Leschner recorded the AC-HRTEM images and contributed to the initial explanation of the observations. Besley and Adriano Santana performed the theoretical modeling and explained the details of the reaction mechanisms and Johannes Biskupek analyzed the images, carried out TEM image simulations, and with Jannik C. Chamberlain designed the experiments, synthesized the materials and analyzed the microscopy data Ute Kaiser contributed to the development of the experimental methodology and discussion of the results Elena Bichoutskaia, Nicholas A. Khlobystov conceived of the initial idea, proposed the general mechanism and wrote the original manuscript Thomas W. ![]()
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