Sieving hydrogen isotopes through two dimensional crystals

TL;DR

This study demonstrates that monolayer graphene and boron nitride can effectively separate hydrogen isotope protons, with deuterons permeating much slower than protons, enabling scalable isotope enrichment at room temperature.

Contribution

It introduces a novel method for hydrogen isotope separation using two-dimensional crystals, highlighting the isotope effect due to zero-point energy differences.

Findings

Deuterons permeate slower than protons through 2D crystals.

Achieved separation factor of approximately 10 at room temperature.

Isotope effect linked to a 60 meV difference in zero-point energies.

Abstract

One-atom-thick crystals are impermeable to atoms and molecules, but hydrogen ions (thermal protons) penetrate through them. We show that monolayers of graphene and boron nitride can be used to separate hydrogen ion isotopes. Employing electrical measurements and mass spectrometry, we find that deuterons permeate through these crystals much slower than protons, resulting in a separation factor of ~10 at room temperature. The isotope effect is attributed to a difference of about 60 meV between zero-point energies of incident protons and deuterons, which translates into the equivalent difference in the activation barriers posed by two dimensional crystals. In addition to providing insight into the proton transport mechanism, the demonstrated approach offers a competitive and scalable way for hydrogen isotope enrichment.