Effective reduction of graphene oxide using sulfur dioxide-containing chemical compounds

The success of the graphene oxide reduction process depends on how similar the product is to pristine graphene. Sulfur oxide, which is a significant industrial waste gas, can be used in the reduction of graphene oxide. In this study, the graphene oxide reduction process was performed by using sulfur oxide with sodium tetraborate decahydrate, l-ascorbic acid, ammonium hydroxide, sodium hydroxide, lithium hydroxide, sodium borohydride and sodium thiosulfate. The carbon-to-oxygen atomic ratio and D-to-G peak ratio of the graphene oxide, which represent the degree of reduction, were 2.64–4 and 0.78–1.80 with the use of sulfur oxide, respectively. The sulfur oxide/sodium borohydride mixture increased the carbon-to-oxygen atomic ratio of the graphene oxide to 11.73, while improving the value of the D-to-G peak ratio at 3.14. The reduced graphene oxide with the highest specific heat capacity was obtained using sodium tetraborate decahydrate, with an improvement of 74.54% compared to graphene oxide. The results show that sulfur oxide, which is harmful to the environment and human health, can be utilized in an effective reduction process, together with other reducing chemicals, to obtain an industrially valuable material, such as reduced graphene oxide.