How Graphene is Transformed into Regular Graphane Structure

TL;DR

This paper computationally demonstrates the stepwise transformation of graphene into a regular chairlike graphane structure through hydrogenation, highlighting the importance of edge atom fixation and a novel algorithm based on unpaired electrons.

Contribution

It introduces a new computational method for modeling graphene hydrogenation into graphane using unpaired electron distribution as a guiding algorithm.

Findings

Complete hydrogenation yields regular graphane structure.

Edge atom fixation is crucial for successful transformation.

The process is effectively modeled with Hartree-Fock and semiempirical AM1 techniques.

Abstract

The paper presents the first computational experiment on the transformation of a graphene sheet (graphene molecule Cn) into graphane (CH)n of regular chairlike structure. The transformation is considered as stepwise hydrogenation of the pristine molecule governed with a particular algorithm. A spatial distribution of the number of effectively unpaired electrons NDA over the carbon carcass lays the algorithm foundation. The atomically mapped high rank NDA values are taken as pointers of target atoms at each reaction step. A complete hydrogenation followed by the formation of regular chairlike graphane structure (CH)n is possible if only all the edge carbon atoms at the perimeter of pristine sheet are fixed thus simulating a fixed membrane, while the sheet is accessible for hydrogen atoms from both side. The calculations were performed within the framework of unrestricted broken symmetry Hartree-Fock approach by using semiempirical AM1 technique.