Graphene structure modification under tritium exposure: 3H chemisorption dominates over defect formation by \b{eta}-radiation

TL;DR

This study reveals that tritium chemisorption causes significant structural changes in graphene, surpassing electron radiation effects, with implications for hydrogen isotope separation technologies.

Contribution

It demonstrates that tritium exposure leads to defect formation in graphene primarily through chemisorption, supported by experimental Raman spectroscopy and molecular dynamics simulations.

Findings

Tritiated graphene shows increased sp3 and vacancy defects.

Tritium effects exceed electron irradiation at similar energies.

Structural modifications may influence hydrogen isotope permeability.

Abstract

Potential structural modifications of graphene exposed to gaseous tritium are important for membrane-based hydrogen isotope separation. Such modifications cannot be explained by electron irradiation alone. Instead, tritiation, caused by the tritium radicals remaining after the decay, is the primary effect causing the modification of the graphene surface, as confirmed by confocal Raman spectroscopy. The effect of the interaction of tritium atoms with the graphene surface exceeds that of electron irradiation at the average energy of the beta particles (5.7 keV). Compared to previously investigated high electron doses in the absence of tritium, remarkably low concentrations of tritium already induce a significant amount of sp3- and vacancy-type defects at short exposure times. Our findings are supported by molecular dynamics simulations of graphene bombardment with tritium atoms. As a consequence, tritium saturation of graphene may alter its permeability for hydrogen isotopes, thus affecting potential applications.