Hydroxyl functionalized graphene as a superior anode material for electrochemical oxidation of methylene blue

Abstract

Graphene and its derivates are among the emerging materials to be studied extensively for many electrochemical applications. The work's objective is to learn the hydroxyl functionalized graphene-modified electrode in the electrochemical oxidation of methylene blue, which is known as a significant industrial dye. Hydroxyl functionalized graphene (G-OH) has been synthesized using graphite as a precursor by a combination of electrochemical exfoliation and sonication methods. Graphite was electrochemically exfoliated in 1,0 M Li2SO4 solution for 2 h to produce oxidized graphene flakes. The oxidized graphene flakes were sonicated in 75% acetone for 2 h to yield G-OH. The product crystal structure and elemental composition were checked with XRD and SEM-EDX. The produced G-OH has an atomic content of C 77,98% and O 22,02%. We also confirmed the product by UV-Vis, FTIR, and Raman spectrometries. The G-OH was deposited on the stainless-steel electrode (SS) and tested in the electrochemical oxidation of methylene blue (MB). The cyclic voltammogram of the bare SS electrode and SS/G-OH modified electrode gives oxidation current peak detected at-0,61 V by 0,47 mA and 5,58 mA, respectively. It suggested a high electrocatalytic ability of the SS/G-OH electrode for the electrochemical oxidation reaction. The electrochemical process by the electrode could degrade >92% of the initial MB within 5 min and > 99% within 30 min. The GC data suggested that MB mainly degraded to CO2 and H2O. This graphene-based electrode could be a potential for the electrochemical oxidation of many organic pollutants to yield environmentally friendly products.