Impact of oxidation morphology on reduced graphene oxides upon thermal annealing

Aleandro Antidormi,Stephan Roche,Luciano Colombo

doi:10.1088/2515-7639/ab5ef2

Abstract

Thermal reduction of graphene oxide (GO) is an essential technique to produce low-cost and higher quality graphene-based materials and composites used today in a plethora of applications. However, despite a demonstrated efficiency of high-temperature annealing in reducing the oxygen content of GO, the impact of the morphology of the initially oxidized samples on the restored sp2 graphene plane versus remaining sp3 imperfections remains unclear and out-of-control. Here using classical molecular dynamics, we simulate the process of thermal reduction on several GO samples for a variety of initial conditions and elucidate how both the concentration of oxygen functional groups and their spatial distribution jeopardize the reduction process efficiency. Our simulations suggest thermal annealing strategies to further optimize the crystallinity of reduced GO, enhancing their transport properties and hence making the resulting composites even more performant for electronic applications.

Highlights

By monitoring the number of sp2 carbon atoms and the oxygen-to-carbon ratio as a function of the annealing temperature, we study the effect of the density of oxidizing agents adsorbed and of the spatial distribution of the functionalized areas onto the efficacy of the thermal treatment
For the given spatial distribution of defected areas, we considered four samples of graphene oxide (GO) differing for the density of the distributed oxidizing agents
We investigate, by means of classical molecular dynamics, the effect of thermal annealing on reducing different samples of GO

Summary

Introduction

Common fabrication methods of graphene include mechanical exfoliation [1], chemical vapour deposition (CVD) [17, 18], epitaxial growth [19], electro-chemical and solution exfoliation [20, 21]. These methods, are known to yield only small-scale production. Reduced GO-based composites are intensively used as additives to plastics, incorporated in glass-reinforced polymers or in concrete to enhance strength and thermal conductivity performances Such graphene-related materials are suitable for coatings and printing applications [23,24,25]

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Conclusion