One-Step Synthesis of Aminobenzoic Acid Functionalized Graphene Oxide by Electrochemical Exfoliation of Graphite for Oxygen Reduction to Hydrogen Peroxide and Supercapacitors

Abstract

Graphene-based materials have attracted considerable attention as promising electrocatalysts for the oxygen reduction reaction (ORR) and as electrode materials for supercapacitors. In this work, electrochemical exfoliation of graphite in the presence of 4-aminebenzoic acid (4-ABA) is used as a one-step method to prepare graphene oxide materials (EGO) functionalized with aminobenzoic acid (EGO-ABA). The EGO and EGO-ABAs materials were characterized by FT-IR spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction and scanning electron microscopy. It was found that the EGO-ABA materials have smaller flake size and higher density of oxygenated functional groups compared to bare EGO. The electrochemical studies showed that the EGO-ABA catalysts have higher activity for the ORR to H2O2 in alkaline medium compared to EGO due to their higher density of oxygenated functional groups. However, bare EGO has a higher selectivity for the 2-electron process (81%) compared to the EGO-ABA (between 64 and 72%) which was related to a lower content of carbonyl groups. The specific capacitance of the EGO-ABA materials was higher than that of EGO, with an increase by a factor of 3 for the materials prepared from exfoliation in 5 mM 4-ABA/0.1 M H2SO4. This electrode material also showed a remarkable cycling capability with a loss of only 19.4% after 5000 cycles at 50 mVs−1.

A Mini-Review on Graphene: Exploration of Synthesis Methods and Multifaceted Properties

“…Graphite oxide is prepared through graphite oxidation using concentrated acids and potent oxidants, relying on methods such as those of Staudenmaier [55], Brodie, or Hummers [56]. The Hummer method is particularly prevalent globally, as it clearly describes the composition of graphite oxide through various models, including the widely used Lerf-Klinowski model [57]. The resultant graphite oxide is characterized by layers containing OH-and epoxy groups at the center, and carboxyl groups at the edges.…”

Electrochemically Exfoliated Graphene Oxide for Simple Fabrication of Cocaine Aptasensors

“…Compared with Hummers’ chemical method of GO synthesis, , the electrochemical exfoliation of graphite in an aqueous solution is more environmentally friendly, simpler, faster, and inexpensive. Through this method, large-scale production of EGO materials can be achieved with different functional groups, structural defects, and tunable sheet sizes by simply adjusting the parameters such as applied voltage and/or distance between the two electrodes, or by using different electrolytes. − With these advantages, EGO materials are ideal for industrial production of electrochemical sensors, but selecting the one that is appropriate for a particular application can be challenging. In our previous study on EGO, a series of large flake size EGO materials (>10 μm) with few layers (from 3 to ∼7) were synthesized in 0.1 M H 2 SO 4 under different electric fields.…”