Sieving hydrogen isotopes through two-dimensional crystals

Area of Science:

• Materials Science
• Physical Chemistry
• Nanotechnology

Background:

• One-atom-thick crystals (2D materials) are typically impermeable to atoms and molecules.
• However, hydrogen ions (protons) can permeate through these 2D materials.
• Separating hydrogen isotopes is crucial for various applications, including nuclear energy and fusion research.

Purpose of the Study:

• To investigate the potential of 2D materials for separating hydrogen ion isotopes.
• To understand the mechanism behind hydrogen isotope permeation through monolayers.
• To develop a scalable method for hydrogen isotope enrichment.

Main Methods:

• Utilized electrical measurements to monitor ion permeation.
• Employed mass spectrometry to identify and quantify hydrogen isotopes.
• Fabricated and tested monolayers of graphene and boron nitride.

Main Results:

• Graphene and boron nitride monolayers demonstrated the ability to separate hydrogen ion isotopes.
• Deuterons permeated through the 2D crystals significantly slower than protons.
• Achieved a separation factor of approximately 10 at room temperature.
• Attributed the isotope effect to a difference in zero-point energies (≈60 meV) between protons and deuterons.

Conclusions:

• Monolayers of graphene and boron nitride can effectively separate hydrogen ion isotopes.
• The observed isotope effect is governed by differences in quantum mechanical zero-point energies.
• This approach offers a competitive and scalable method for hydrogen isotope enrichment.