Defect engineering of ZnO nanoparticles by graphene oxide leading to enhanced visible light photocatalysis

Ahmed, Gulzar; Hanif, Muddasir; Zhao, Lizhong; Hussain, Mazhar; Khan, Javid; Liu, Zhongwu

doi:10.1016/j.molcata.2016.10.026

Cited by 70 publications

(18 citation statements)

References 65 publications

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“…However, the presence of 4 oxygen vacancies in ZnO as surface defects plays an important role in optical absorption in visible light region. Theoretical calculations by first principle density functional theory (DFT) concluded that the valence states near Fermi level originated from the O2p and Zn3d states in the valence band can lead to the electronic transitions in visible region [ 54 , 55 ].…”

Section: Resultsmentioning

confidence: 99%

Biosynthesis Microwave-Assisted of Zinc Oxide Nanoparticles with Ziziphus jujuba Leaves Extract: Characterization and Photocatalytic Application

et al. 2021

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The present work is intended to biosynthesize zinc oxide nanoparticles (ZnO NPs) via facile and modern route using aqueous Ziziphus jujuba leaves extract assisted by microwave and explore their photocatalytic degradation of methyl orange anionic dye and methylene blue cationic dye under solar irradiation. The biosynthesized microwave assisted ZnO NPs were characterized and the results showed that ZnO NPs contain hexagonal wurtzite and characterized with a well-defined spherical-like shape with an outstanding band gap (2.70 eV), average particle size of 25 nm and specific surface area of 11.4 m2/g. The photocatalytic degradation of the MO and MB dyes by biosynthesized ZnO NPs under solar irradiation was studied and the results revealed the selective nature of the ZnO NPs for the adsorption and further photocatalytic degradation of the MO dye compared to the MB dye. In addition, the photocatalytic degradation of MO and MB dyes by the ZnO NPs under solar radiation was fitted by the first-order kinetics. Moreover, the photodegradation mechanism proposed that superoxide ions and hydroxyl radicals are the main reactive species.

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Section: Resultsmentioning

confidence: 99%

Biosynthesis Microwave-Assisted of Zinc Oxide Nanoparticles with Ziziphus jujuba Leaves Extract: Characterization and Photocatalytic Application

et al. 2021

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“…The formation of heterojunctions at the surface of ZnO@BC nanoparticles could be responsible for the enhancement in the number of Ov. Ov could promote the charge separation effectively, extend the photo response region of the photocatalyst and provide active sites for the photocatalytic reaction [55].…”

Section: Xps Analysismentioning

confidence: 99%

Synthesis of ZnO Nanoparticles Loaded on Biochar Derived from Spartina alterniflora with Superior Photocatalytic Degradation Performance

Hua

Wang³

et al. 2021

Nanomaterials

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Spartina alterniflora is an invasive plant from coastal wetlands, and its use in applications has garnered much interest. In this study, a composite photocatalyst (ZnO@BC) was synthesized by preparing zinc oxide (ZnO) nanoparticles with S. alterniflora extracts, S. alterniflora, and one-step carbonization, which was characterized using scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy (UV–vis DRS), photoluminescence (PL) and N2 adsorption–desorption isotherm. The degradation capacity and mechanism of malachite green (MG) using ZnO@BC were analyzed under visible irradiation, and the degradation products of malachite green were detected by LC–MS. The results show that ZnO@BC has a larger surface area (83.2 m2/g) and various reactive groups, which enhance its photocatalytic efficiency, with the presence of oxygen vacancy further improving the photocatalytic activity. The total removal rate of malachite green (400 mg/L) using ZnO@BC is up to 98.38%. From the LC–MS analysis, it could be concluded that malachite green is degraded by demethylation, deamination, conjugate structure and benzene ring structure destruction. This study provides a novel idea for the high-value utilization of S. alterniflora.

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“…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].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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Graphene oxide (GO) is used to enhance the photocatalytic activity of ZnO nanoparticles for the degradation of vanillic acid (VA) under simulated solar light and visible-LED (λ > 430 nm). ZnO-GO composites are prepared by a mixing and sonication process with different GO loadings (i.e., from 1.8 to 6.5 wt.%). The materials are extensively characterized by thermogravimetric analysis (TGA), physisorption of N2, X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), point of zero charge (pHPZC), and UV-Vis diffuse reflectance spectroscopy (DRUV). The presence of GO increases the photocatalytic activity of all the prepared composites in comparison with the pristine ZnO. The highest photocatalytic activity is found for the composite containing 5.5 wt.% of GO (i.e., ZnO-GO5.5), reaching a VA degradation of 99% and 35% under solar light and visible-LED, respectively. Higher TOC removal/VA degradation ratios are obtained from the experiments carried out under visible-LED, indicating a more effective process for the mineralization of VA than those observed under simulated solar light. The influence of hole, radical, and non-radical scavengers is studied in order to assess the occurrence of the reactive oxygen species (ROS) involved in the photocatalytic mechanism. The study of the photo-stability during three reuse experiments indicates that the presence of GO in the composites reduces the photocorrosion in comparison with pristine ZnO.

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Defect engineering of ZnO nanoparticles by graphene oxide leading to enhanced visible light photocatalysis

Cited by 70 publications

References 65 publications

Biosynthesis Microwave-Assisted of Zinc Oxide Nanoparticles with Ziziphus jujuba Leaves Extract: Characterization and Photocatalytic Application

Biosynthesis Microwave-Assisted of Zinc Oxide Nanoparticles with Ziziphus jujuba Leaves Extract: Characterization and Photocatalytic Application

Synthesis of ZnO Nanoparticles Loaded on Biochar Derived from Spartina alterniflora with Superior Photocatalytic Degradation Performance

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

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