Graphane as polyhydride of graphene. Computational synthesis applied to two-side membrane

TL;DR

This paper uses computational quantum chemistry to investigate the hydrogenation process of graphene, focusing on how hydrogen atoms attach and the sequence of adsorption, providing insights into graphane formation.

Contribution

It applies semiempirical AM1 Hartree-Fock calculations to analyze hydrogen attachment patterns on graphene, addressing key questions about the hydrogenation mechanism.

Findings

Atomic hydrogen is more probable than molecular hydrogen attachment.

Hydrogen atoms tend to attach to specific carbon sites influenced by conformational patterns.

Sequential adsorption follows a pattern related to cyclohexane conformers.

Abstract

A great efficacy of molecular quantum chemistry applied to basic graphene problems has been recently demonstrated by the authors when studying the formation of peculiar composites between carbon nanotubes and graphene as well as considering tensile deformation and fracture of a graphene sheet in due course of a mechanochemical reaction. The optimistic results obtained in the studies make it possible to shift attention from the solid state problems and consider the graphane formation as multistep hydrogenation of the pristine molecule. To proceed we have to answer the following questions: 1) which kind of the hydrogen adsorption, namely, molecular or atomic, is the most probable; 2) what is a characteristic image of the hydrogen atom attachment to the substrate; 3) which carbon atom (or atoms) is the first target subjected to the hydrogen attachment and how carbon atoms are selected for the next steps of the adsorption; 4) is there any connection between the sequential adsorption pattern and cyclohexane conformers. First results obtained on this way are presented in the current paper. The calculations were performed within the framework of unrestricted broken symmetry Hartree-Fock approach by using semiempirical AM1 technique.