Reduction of graphene oxide by UHV annealing.

A series of chemically treated graphene oxide (GO) samples, destined for the preparation of several composite materials, was studied by X‐ray photoelectron spectroscopy (XPS). From their comparison, the 3‐mercaptopropyl trimethoxysilane was identified as the most effective reducing agent among the used procedures. The influence of ultrahigh vacuum annealing up to 600°C on the chemical composition and carbon electronic configuration in reduced GO samples was further investigated by XPS and Auger electron spectroscopy. All the samples before and after thermal treatments were analyzed in situ by XPS and Auger electron spectroscopy, paying a particular attention to the shape of C KVV spectra described by the values of D parameter. The changes of chemical composition and carbon configuration reflected in the D parameter revealed the full reduction of GO to graphene after annealing in ultrahigh vacuum at 600°C. The successful reduction of GO to graphene was also confirmed by Raman spectroscopy. Obtained bulk samples of graphene aggregates remained stable in air, testifying the irreversibility of this reduction. [ABSTRACT FROM AUTHOR]