Site dependent hydrogenation in Graphynes: A Fully Atomistic Molecular Dynamics Investigation

TL;DR

This study uses atomistic molecular dynamics to explore how hydrogen atoms bond to different types of graphyne, revealing that hydrogenation is highly site-dependent and varies among ALPHA, BETA, and GAMMA structures.

Contribution

It provides the first detailed atomistic simulation analysis of hydrogenation processes in various graphyne forms, highlighting site-specific reactivity and structural effects.

Findings

Hydrogenation is more complex in graphynes than in graphene.

Sp-hybridized carbons are the preferred sites for hydrogen bonding.

Hydrogenation effectiveness varies among ALPHA, BETA, and GAMMA graphynes.

Abstract

Graphyne is a generic name for a carbon allotrope family of 2D structures, where acetylenic groups connect benzenoid rings, with the coexistence of sp and sp2 hybridized carbon atoms. In this work we have investigated, through fully atomistic reactive molecular dynamics simulations, the dynamics and structural changes of the hydrogenation of ALPHA, BETA, GAMMA graphyne forms. Our results showed that the existence of different sites for hydrogen bonding, related to single and triple bonds, makes the process of incorporating hydrogen atoms into graphyne membranes much more complex than the graphene ones. Our results also show that hydrogenation reactions are strongly site dependent and that the sp-hybridized carbon atoms are the preferential sites to chemical attacks. In our cases, the effectiveness of the hydrogenation (estimated from the number of hydrogen atoms covalently bonded to carbon atoms) follows the ALPHA, BETA, GAMMA graphyne structure ordering.