Effect of long-term ageing on graphene oxide: structure and thermal decomposition.

Chen Li,Jun Yan,Ke Niu,Ran Zhao,Yanling Lu,Shiguo Du,Weibo Yu

doi:10.1098/rsos.202309

Abstract

After long-term ageing, the structure of graphene oxide prepared by the modified Hummers method changed. Because of the desorption of oxygen-containing functional groups, the C/O ratio of graphene oxide increased from 1.96 to 2.76. However, the average interlayer distance decreased from 0.660 to 0.567 nm. The content of -CH- and -CH2- decreased; however, the type of oxygen-containing functional groups did not change. Moreover, ID/IG increased from 0.87 to 0.92, indicating that the defect density decreased because of desorbing oxygen functional groups after ageing. When the temperature exceeded 60°C, CO2 produced by decomposing graphene oxide was detected. The thermal decomposition changed after ageing. The decomposition peak temperature decreased from 216°C to 195°C. The CO2 amount produced remained almost unchanged; however, the amount of CO, SO2 and H2O decreased. After ageing, the apparent activation energy of graphene oxide decreased from 150 to 134 kJ mol−1.

Highlights

Graphene oxide, commonly referred to as functionalized graphene, is a graphene derivative with a six-membered ring structure similar to that of graphene
4 After ageing, the full width at half maximum (FWHM) of the diffraction peak of the (002) plane of graphene oxide increased from 0.53527° to 0.91882°
The results presented in this study suggest that the aliphatic hydrocarbon groups and oxygen-containing functional groups in the graphene oxide structure are degraded during long-term ageing

Summary

Introduction

Commonly referred to as functionalized graphene, is a graphene derivative with a six-membered ring structure similar to that of graphene. Researchers believe that oxygen-containing groups of graphene oxide are primarily the hydroxyl, carboxyl and epoxy groups [1]. There may be carbonyl groups, semiquinones, tertiary carbon hydroxyl groups, ethers, quinones, furan-like bridges and five-membered lactones [2]. The epoxy and hydroxyl groups are located on the basal plane of graphene royalsocietypublishing.org/journal/rsos R.

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Conclusion