Antioxidant Activity of Graphene Quantum Dots Prepared in Different Electrolyte Environments

Abstract

Antioxidants can reduce or inhibit damage such as oxidative decay caused by elevated levels of free radicals. Therefore, pursuing antioxidants with excellent properties has attracted more and more attention. Graphene quantum dots (GQDs) are considered a promising material because of their good free radical scavenging activity, low toxicity, and excellent water solubility. However, their scavenging efficiency, antioxidant mechanism, and effective control methods need to be improved. Herein, in order to further reveal the antioxidant mechanism of GQDs, the role of electrolytes in improving the antioxidant activity of GQDs is explored. In addition, 1,1-diphenyl-2-picrazine (DPPH∙), hydroxyl (∙OH), and superoxide (∙O2−) free radicals are used to evaluate the antioxidant activity of the as-prepared GQDs. Combined with transmission electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and cyclic volt–ampere characteristic curves, the effects of an electrolytic environment on the surface functional groups, charge transfer capability, and defect states of GQDs are obtained. The antioxidant mechanism of GQDs and how to improve their antioxidant activity are further elucidated.

Optimization of Glutathione Adhesion Process to Modified Graphene Surfaces

“…It must be remembered that possible applications are limited not only to pure graphene; graphene derivatives such as graphene oxide and reduced graphene oxide are also included in the area of interest of biomedical use. Furthermore, graphene derivatives can be functionalized much easier by adding metal ions, molecules of metal oxides, as well as organic and inorganic polymers [ 4 , 5 , 6 ]. All these adjustments greatly expand the range of modifications of generated graphene nanocomposites, both as 3D and 2D materials, simultaneously opening vast possibilities of detection techniques.…”

Commercial Wheat and Oat Flour Derived Fluorescent Carbon Quantum Dots through Sustainable Hydrothermal Synthesis and Their Biological Activities

“…DPPH is a stable nitrogen‐free radical‐containing molecule with a deep purple color that turns yellow upon reacting with antioxidant substances, resulting in a decrease in absorbance at 517 nm [45] . Previously, the antioxidant activity of CDs has been reported in many studies [46] . Here, we studied the antioxidant potential of different concentrations of W‐ and O‐CQDs using DPPH.…”

“…[45] Previously, the antioxidant activity of CDs has been reported in many studies. [46] Here, we studied the antioxidant potential of different concentrations of W-and O-CQDs using DPPH.…”

Eco-Friendly and Sustainable Pathways to Photoluminescent Carbon Quantum Dots (CQDs)

“…The statistical results indicate that the average particle diameters of GQDs-PBS, GQDs-NaOH, and GQDs-KCl are 3.19 ± 0.90, 3.76 ± 0.70, and 3.36 ± 0.70 nm, respectively. Furthermore, it has been reported that there is no significant difference in the shape or size of the samples, indicating that the three electrolytes have similar effects on the formation of GQDs [ 187 ].…”