Quantum tunneling of thermal protons through pristine graphene

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Atomically thin membranes are crucial for hydrogen isotope separation.
• Graphene-based membranes exhibit significant differences in proton and deuteron permeability.
• Understanding these differences is key for developing advanced separation technologies.

Purpose of the Study:

• To investigate the distinct permeability mechanisms of protons and deuterons in graphene membranes.
• To elucidate the role of quantum nuclear effects in ion transport.
• To provide insights for designing efficient nanostructured separation membranes.

Main Methods:

• Theoretical modeling of ion transport through graphene.
• Analysis of quantum tunneling and quasi-classical transport regimes.
• Temperature and mass dependence studies of ion permeability.

Main Results:

• Proton permeability is governed by quantum tunneling, while heavier isotopes like deuterons exhibit quasi-classical transport.
• Quantum nuclear effects significantly influence proton transport, with large temperature and mass dependencies.
• Activation energy and prefactor for protons are substantially modified by quantum effects.

Conclusions:

• The mechanism of hydrogen isotope ion transport through graphene membranes is mass-dependent.
• Quantum effects play a critical role in proton transport, distinguishing it from heavier isotopes.
• Findings offer new strategies for controlling ion transport in nanoseparation membranes.