Photocatalytic Activity of Graphene Oxide/Zinc Oxide Nanocomposites with Embedded Metal Nanoparticles for the Degradation of Organic Dyes

Abstract

Nanocomposite materials based on metal nanoparticles and graphene oxide (GO) have gained increasing attention for their wide range of potential applications in various materials science fields. In this study, an efficient photocatalyst based on GO/ ZnO nanocomposites with embedded metal nanoparticles was successfully synthesized via a simple one-pot method. The synthesized nanocomposites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity of the synthesized nanocomposites was tested in the degradation of methylene blue (MB) dyes, as a model of water pollutants. A catalytic activity of 84% was achieved using a nanocomposite with a percentage of 3.125% GO, after 90 min sunlight irradiation. Furthermore, embedded copper and silver nanoparticles were used as dopants to study their effects on the activity of the photocatalyst. The GO−ZnO−Cu nanocomposite showed that the activity toward MB degradation was decreased by 50%, while a significant increase in the activity of MB degradation was achieved by the GO−ZnO−Ag nanocomposite. The removal efficiency of MB by the GO−ZnO−Ag nanocomposite reached 100% after 40 min of sunlight irradiation. Thus, the GO−ZnO−Ag nanocomposite has the potential to be an efficient adaptable photocatalyst for the photodegradation of organic dyes in industrial wastewater.

Photocatalytic Perfomance of ZnO-Graphene Oxide Composites towards the Degradation of Vanillic Acid under Solar Radiation and Visible-LED

“…It can be considered as a suitable successor of the benchmark TiO 2 semiconductor due to its similar properties such as strong oxidation ability, good photocatalytic properties, chemical stability, biocompatibility, non-toxicity, high photosensitivity, and electronic and piezoelectric properties, among others [13][14][15]. This semiconductor usually exists in one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) associations [16], and has been used in a wide range of applications, such as sensors [17], photocatalysis [14,[18][19][20][21], transistors, solar cells [22,23], etc. It is well known that the use of ZnO in photocatalysis displays some drawbacks such as: (i) the limitation of its use in the visible range due to its wide band gap [24]; (ii) particle aggregation during photocatalytic reactions which significantly restrict the photocatalytic activity of ZnO at a large scale [25]; and (iii) the rapid recombination of the photogenerated electron-hole pairs [26,27].…”

A Comparative Study of Cerium- and Ytterbium-Based GO/g-C3N4/Fe2O3 Composites for Electrochemical and Photocatalytic Applications

“…Nearly 3 mL for each reading was used and showed a noticeable decrease in absorbance values, thus confirming the degradation of dyes [41,42]. The photocatalytic efficiency of the nanocomposites used has been worked out by using Equation (3) [43,44] as…”

“…where X, Eg, ECB, and EVB are the expressions of electro negativity, band gap, conduction band edge potential, and valence band edge potential, respectively, whereas Eef is the free e-energy relative to the H-scale (4.25 eV). The band gap for Fe2O3 is 2.3 eV and 2.7 eV for the graphitic carbon nitride material (Table 1), as both materials are key to establishing The photocatalytic efficiency of the nanocomposites used has been worked out by using Equation (3) [43,44]…”

Review of the Advancements on Polymer/Metal Oxide Hybrid Nanocomposite‐Based Adsorption Assisted Photocatalytic Materials for Dye Removal

“…These active species again react with organic pollutants to form degradation products like water, carbon dioxide, and other mineralized nontoxic products. [33][34][35] Both direct and indirect photocatalysis occur at the same time. However, the principal degradation path depends on the nature of the species' physicochemical interaction with the catalyst surface.…”

“…Adsorption of dye molecules to the photocatalyst surface dye þ catalyst � �! dye adsorbed product (34) Light initiated electron excitation from MO x (ZnO or SnO 2 ) and polymer (P = polyaniline or polypyrrole)…”