Graphene oxide (GO) and reduced graphene oxide (rGO) have been widely used for high capacity energy conversion and storage in fuel cells and lithium ion batteries, respectively. Particularly, for proton exchange membrane fuel cells (PEMFC) applications the incorporation of sulfonic acid functional groups (-SO3H) into GO/rGO structure has emerged as a powerful strategy to produce promising new support of noble catalysts and ionomer materials, due to a significant increase in the hydrophilicity of rGO improving the nano-catalyst dispersion and ion-exchange capacity (IEC). In this study, GO was synthesized and sulfonated (sGO) for the development of electrodes and membranes. GO was obtained by a modified Hummer’s method from graphite powder, thermally reduced and sulfonated by means of two sulfonating agents: sulfuric acid and aryl diazonium salt of sulfanilic acid. The influence of the sulfonation agents on the physicochemical properties of rGO-SO3H was evaluated through XRD, TGA, FT-IR and Raman techniques. Electrochemical behavior of both materials as modified glassy carbon electrode was investigated in K3FeCN6 solution as a reference redox system. The results demonstrated that the sulfonated materials have superior electron transfer activity and electrochemical properties compared to GO. In addition, the IEC for a commercial membrane modified with rGO-SO3H improved significantly.