Reduced Graphene Oxide–Metal Oxide Nanocomposites (ZrO2 and Y2O3): Fabrication and Characterization for the Photocatalytic Degradation of Picric Acid

Abstract

Herein, reduced graphene-oxide-supported ZrO2 and Y2O3 (rGO-ZrO2 and rGO-Y2O3) nanocomposites were synthesized by hydrothermal method and used as the catalysts for photodegradation of picric acid. The structural and morphological properties of the synthesized samples were characterized by using an X-ray diffractometer (XRD), scanning electron microscope (SEM) with energy dispersive absorption X-ray spectroscopy (EDAX), UV-Vis spectrophotometer, Raman spectrophotometer and Fourier transformation infrared spectrophotometer (FT-IR) techniques. In this work, the wide band gap of the ZrO2 and Y2O3 was successfully reduced by addition of the reduced graphene oxide (rGO) to absorb visible light for photocatalytic application. The performance of as synthesized rGO-ZrO2 and rGO-Y2O3 nanocomposites in the photocatalytic degradation of picric acid were evaluated under UV light irradiation. The photodegradation study using picric acid was analyzed with different energy light sources UV (254, 365 and 395 nm), visible light and sunlight at different pH conditions (pH = 3, 7 and 10). The photocatalytic activity of rGO-ZrO2 and rGO-Y2O3 nanocomposites showed excellent photocatalytic activity under optimum identical conditions with mild variations in pH 3. Compared to rGO-Y2O3, the rGO-ZrO2 nanocomposite showed a better action, with a degradation percentage rate of 100, 99.3, 99.9, 100 and 100% for light conditions of UV-252, 365, 395, visible and sunlight, respectively. The excellent degradation efficiency is attributed to factors such as oxygen-deficient metal oxide phase, high surface area and creation of a greater number of hydroxyl groups.

Graphene Loaded ZrO2 Nanocomposite for Antioxidant, Dye Removal, Electrochemical and Green Sensor Studies

“…When exposed to visible light, these interactions cause and speed up the creation of electron‐hole pairs (e − /h + ), as shown in equations 7 and 8. Photoexcitation generates electrons, which flow from ZrO 2 ′s conduction band (CB) to the rGO surface [55] …”

“…Photoexcitation generates electrons, which flow from ZrO 2 's conduction band (CB) to the rGO surface. [55] This movement reduces oxygen molecules, resulting in superoxide radicals (O 2 À ) (see equation 9). Furthermore, hydroxyl radicals (OH À ) are produced by an electron deficiency (hole) in the valence band (VB), as shown in equation (10).…”

Photodegradation of Ciprofloxacin and Levofloxacin by Au@ZnONPs-MoS2-rGO Nanocomposites

“…Figure 3 shows the Raman spectra of rGO, ZnONPs, MoS2, and the 5%Au@ZnONPs-3%MoS2-1%rGO catalyst. rGO (Figure 3a) shows two peaks at 1350 cm -1 and 1586 cm -1 , corresponding at the D and G bands, respectively, and represent the presence of carbon atom lattice defects and in-plane stretching vibration from sp 2 hybridization of carbon [32]. The ZnONPs (Figure 3b) shows different peaks at ca.…”