Hydrogenation of graphene in view of odd electrons correlation

TL;DR

This paper investigates the strong correlation of odd electrons in graphene and introduces an algorithmic approach to predict and design hydrogenation processes, revealing complex dependencies affecting hydride formation.

Contribution

It presents a novel correlation-based computational algorithm for predicting graphene hydrogenation pathways and outcomes considering various experimental conditions.

Findings

Hydrogenation of graphene is a complex, multimode process.

The algorithm can predict the formation of graphane under specific conditions.

Hydride products depend on membrane fixation and hydrogen accessibility.

Abstract

The paper presents evidence of a rather strong correlation of odd electrons in the singlet state of graphene. Due to the correlation, the chemical modification of graphene can be considered following a certain algorithmic computational procedure. Originated due to the correlation and distributed over the carbon atoms of graphene membrane with fraction numbers NDA, effectively unpaired electrons lay the algorithm foundation. The highest NDA value points to the target atom that enters a chemical reaction at the considered step. Following the pointers, a stepwise design of polyderivatives can be performed. Applied to the hydrogenation, the algorithmic design has exhibited that graphene hydrogenation should be attributed to a highly complicated event, whose final hydride products depend on a number of factors such as: 1) the manner of the graphene membrane fixation; 2) the accessibility of the membrane both sides to hydrogen; 3) the composition (molecular or atomic) of the hydrogen. In general, the hydride formation is multimode in regards composition and structure. Thus, the formation of 100% hydride with regular chairlike hexagonal packing of CH units which can be attributed to graphane is possible if only the graphene membrane is fixed over perimeter while its basal plane is accessible to hydrogen atoms from both sides.