▎ 摘　　要

We present a study of the process of reduction of thin graphene oxide (GO) films consisting.of flakes with lateral size of up to 100 mu m through soft ultraviolet irradiation in the argon atmosphere. It was found out that the reduction process leads to a significant decrease in the overall content of the basal-plane functional groups, namely, epoxides and hydroxyls, but with simultaneous increase in the total number of the edge-located carboxyl groups. Obtained transmission electron microscopy images showed that this effect is related to formation of nanoscale holes in the course of reduction. Based on the data obtained, we have proposed a mechanism of the observed GO structural modification in terms of photoinduced chemical reactions between the carbon network and functional groups. These reactions result in progressive growth of the initially existing and newly formed vacancies with formation of the nanoholes with size of up to 100 nm. Thus, reduced graphene oxide films with the restored conjugated network and many edges terminated with carboxyl groups can be probably obtained via the photoreduction process in the argon atmosphere and further used in several applications, such as production of gas sensors and organic light-emitting devices.