Engineering Hydroxyl Functionalization Enables Atomically Precise ZnO Nucleation on Defective Graphene

TL;DR

Researchers found that adding hydroxyl groups to graphene helps grow ZnO more efficiently at the atomic level.

Contribution

This study reveals how hydroxyl groups on graphene enhance ZnO nucleation through noncovalent interactions.

Findings

Hydroxyl groups stabilize DEZ adsorption and lower activation energy for ZnO growth.

Increasing hydroxyl groups makes ZnO nucleation more thermodynamically and kinetically favorable.

Noncovalent interactions like hydrogen bonds play a key role in facilitating the initial reaction.

Abstract

The synergy between graphene and ZnO in creating hybrid
nanomaterials
with novel properties of interest for the technological industry requires
the development of processes and techniques that enable their precise
production at the nanoscale. Therefore, understanding the atomic and
molecular mechanisms that lead to their creation is imperative for
controlling each involved step in their formation, enhancing their
efficiency. This work sheds light on the first atomic layer half-cycle
for the growth of ZnO on graphene with a hydroxyl-functionalized monovacancy.
We performed quantum mechanical calculations, considering a trapping-mediated
mechanism and diethylzinc (DEZ) as the precursor. The results suggest
that neighboring hydroxyl groups facilitate DEZ adsorption and minimize
the activation energy. This is linked to the role of hydroxyl groups
in the formation of noncovalent interactions such as weak van der
Waals and C–H···O and O–H···O
hydrogen bonds, which stabilize the systems and facilitate the first
partial reaction. By comparing the response in systems with one, two,
and three hydroxyl groups, it was found that as these functional groups
increased in quantity, the reactions were both thermodynamically and
kinetically more favorable. Thus, it can be concluded that incorporating
hydroxyl groups on graphene through pretreatment may considerably
increase the initial growth rate of ZnO.

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