For RGO in different aqueous electrolytes, a sharp redox peak was observed in acidic medium whereas rectangular CV profile was observed in 6 M KOH solution (OF-1). This is because of the fact that the acidic oxygen functionalities such as carboxylic acid, phenolic interact with hydroxide ions to produce the corresponding anionic version while such kind of faradaic processes are no longer feasible with basic oxygen functionalities such as quinone. It was reported that the better capacitance was observed by the oxygen functionalized carbon in acidic electrolyte owing to the enhanced mobility as well as the easier accessibility towards the electrode by H + ions . Furthermore, the basic oxygen functionalities such as carbonyl and quinone too contribute pseudocapacitive nature by participating the faradaic reactions with protons from acidic electrolyte. From these discussions, it is highly evident that groups such as phenolic and carboxylic acid are acids whereas groups such as carbonyl and quinone are regarded as bases which agree well as per Lowry-Bronsted concept of acids and bases. The electrochemical reactions of acidic and basic oxygen functionalities with H2SO4 are shown as below: