1 / 24

Adsorption on Single-Walled Carbon Nanohorns

Adsorption on Single-Walled Carbon Nanohorns. Adam Scrivener. What are carbon nanohorns?. Nanostructures made from graphene sheets, forming a dahlia-like structure. Surface area is much greater than graphene, which makes nanohorns a promising material for gas adsorption. What is adsorption?.

kaycee
Download Presentation

Adsorption on Single-Walled Carbon Nanohorns

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Adsorption on Single-Walled Carbon Nanohorns Adam Scrivener

  2. What are carbon nanohorns? • Nanostructures made from graphene sheets, forming a dahlia-like structure. • Surface area is much greater than graphene, which makes nanohorns a promising material for gas adsorption.

  3. What is adsorption? • Adsorption is the adhesion of atoms or molecules from a gas, liquid, or dissolved solid to a surface. • Caused by van der Waals force between an adsorbate (gas molecules/atoms) and an adsorbent (Carbon atoms).

  4. Applications of adsorption • Gas storage: gas particles can be stored at very high density using nanohorns, due to the adsorption process and high surface area per volume ratio. • Gas separation: Several materials, including carbon nanohorns, can be used as a filter in factories to reduce greenhouse gas emissions such as methane and CO2. • Gas sensing: The ability to monitor how much gas is in a system is invaluable, and carbon-based materials such as carbon nanohorns are perfect for this because of their large specific surface areas.

  5. The van der Waals force • The van der Waals force is the sum of the attractive forces between molecules other than those due to covalent bonds or electrostatic interactions involving ions. • There are no covalent bonds or ions involved in the systems which we deal with, so the electrostatic forces can be disregarded.

  6. The Lennard-Jones potential • Approximates the interactions between the Carbon atoms in the nanohorns and the gaseous adsorbate • Incorporates the attractive portion of the van der Waals force and the repulsive forces caused by overlapping electron orbitals.

  7. Monte Carlo Simulations • An efficient method of observing the equilibrium properties of the nanohorn/gas system. • Simulations can be combined with experiments to make it easier to interpret the results • Using simulations, we can explore parameters that are not possible in a real-world experiment. E.G., we can set any temperature or pressure that we want, or add impurities to the adsorbent easily.

  8. The Grand Canonical Monte Carlo Algorithm • Start with an arbitrary configuration of particles.

  9. The Grand Canonical Monte Carlo Algorithm • Start with an arbitrary configuration of particles. • Randomly choose whether to: • Move a particle from the vapor into the system in a random location.

  10. The Grand Canonical Monte Carlo Algorithm • Start with an arbitrary configuration of particles. • Randomly choose whether to: • Move a particle from the vapor into the system in a random location. • Move a random particle from the system into the vapor.

  11. The Grand Canonical Monte Carlo Algorithm • Start with an arbitrary configuration of particles. • Randomly choose whether to: • Move a particle from the vapor into the system in a random location. • Move a random particle from the system into the vapor. • Choose a random particle already in the system and move it in a random direction within some fixed distance ∆.

  12. The Grand Canonical Monte Carlo Algorithm • Start with an arbitrary configuration of particles. • Randomly choose whether to: • Move a particle from the vapor into the system in a random location. • Move a random particle from the system into the vapor. • Choose a random particle already in the system and move it in a random direction within some fixed distance ∆. • Repeat until the system is in equilibrium.

  13. (After many iterations)

  14. Energy of Krypton-nanohorn system Egg Egg Egg Egs Egs Egs 60K 77.4K 40K

  15. Krypton Adsorption - Pressure vs. Temperature 60K 77.4K 40K

  16. Atoms inside

  17. Krypton Adsorption - Pressure vs. Temperature 60K 77.4K 40K

  18. Atoms inside and in between nanohorns

  19. Krypton Adsorption - Pressure vs. Temperature 60K 77.4K 40K

  20. Atoms inside and on surface of nanohorns

  21. Future plans • Simulate Neon instead of Krypton • Use Neon data to compare to already observed data from real-world experiments. • This will further affirm that our simulations accurately represent the equilibrium state of the nanohorn adsorption systems. • We plan to simulate CO2 as well, and, similarly to Neon, compare to data from real-world experiments.

More Related