Enhancing the photocatalytic efficiency of ZnO: Defects, heterojunction, and optimization

Abebe, Buzuayehu; Murthy, H. C. Ananda; Zereffa, Enyew Amare

doi:10.1016/j.enmm.2020.100336

Cited by 59 publications

(40 citation statements)

References 153 publications

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“…The ROS generation, particularly, during characteristic wavelength of light absorption was indicated as the main mechanism of antibacterial activity [ 13 , 14 ]. The ROS was generated following different mechanisms such as surface adsorption of the bacteria, generation of electron/hole pairs, the reaction of generated pairs with oxygen/water, and formation of different intermediates [ 15 ]. However, the release of antimicrobial ions such as Zn +2 , Mn +3 , and Fe +3 [ 16 ] and the electrostatic interaction of NPs with microorganisms [ 17 ] was also reported to be the other decent antibacterial mechanism.…”

Section: Introductionmentioning

confidence: 99%

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A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

et al. 2020

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Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant extract that control the morphology and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to volume ratio, and also improves the stability towards dissolution and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphological analysis using scanning electron microscopy, field emission-scanning electron microscopy, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstract Graphical abstract showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.

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Section: Introductionmentioning

confidence: 99%

“…The heterojunction can be made either with the same or different bandgap metal oxides. It may form either in the n–n or p–n procedure for binary metal oxides and either p–n–n or n–n–n approach for ternary heterojunction [ 15 , 65 ].…”

Section: Introductionmentioning

confidence: 99%

A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

et al. 2020

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“…Industrialization has led to an increase in the discharge of harmful air and water pollutants such as CO and SO 2 into the atmosphere and harmful azo dyes in wastewater. It has been estimated that approximately 500 tons of various dyes are discharged into industrial wastewater and a major portion (~ 80%) of them is from textile industry [ 11 ]. Chemical toxins and organic fuels form part of air pollution while dangerous dyes from water bodies affect earth’s ecosystems, thereby increasing the importance of technology used to detect and prevent such pollutants from harming the environment.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic, Bactericidal and Molecular Docking Analysis of Annealed Tin Oxide Nanostructures

et al. 2021

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Nanosized tin oxide was fabricated with a simple and cost-effective precipitation technique and was analyzed by performing x-ray powder diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, high-resolution transmission electron (HR-TEM) microscopy, energy-dispersive x-ray (EDX) and UV–Vis spectroscopy. The XRD results revealed that tin oxide particles possessed typical orthorhombic structure and exhibited improved crystallinity with annealing. Calcination at 250 °C produced predominantly orthorhombic SnO which transformed to SnO2 at higher temperatures of 500 and 750 °C. HRTEM and FESEM images showed existence of agglomeration within the particles of tin oxide. The absorption was found to increase up to a certain annealing temperature followed by a decrease, which was recorded via UV–Vis spectroscopy. The effect of annealing temperature on dye decomposition behavior of synthesized photocatalysts was studied. It was noted that annealing temperature affects the size of synthesized particles, band gap width and photoactivity of tin oxide. The sample prepared at 500 °C followed first-order kinetics and exhibited maximum photocatalytic reactivity toward methylene blue. The experimental results obtained from the present study indicate that SnO2 is a promising and beneficial catalyst to remove contaminants from wastewater and environment. The antimicrobial evaluation of SnO annealed at 500 °C against selected targets such as E. coli and S. aureus depicted significant inhibition zones in comparison with 250 and 750 °C samples. Furthermore, molecular docking predictions of SnO2 nanoparticles (NPs) were performed against active pocket of β-lactamase and DNA gyrase enzyme belonging to cell wall and nucleic acid biosynthetic pathway, respectively. The fabricated NPs showed good binding score against β-lactamase of both E. coli (− 5.71 kcal/mol) and S. aureus (− 11.83 kcal/mol) alongside DNA gyrase (− 9.57 kcal/mol; E. coli and − 8.61 kcal/mol; S. aureus). These in silico predictions suggested SnO2 NPs as potential inhibitors for selected protein targets and will facilitate to have a clear understanding of their mechanism of action that may contribute toward new antibiotics discovery.

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“…However, the material presents some intrinsic drawbacks that have severely limited its applications in the photocatalytic field, as the UV region (3.3 eV) falling band gap and the high recombination rate [26,29]. Different types of techniques have been developed and proposed to increase the photocatalytic ability of ZnO overcoming its limitations such as the intrinsic and extrinsic doping [30][31][32], the formation of solid solutions and the creation of heterojunctions with other oxides [33][34][35]. This last strategic approach has been considered of particular importance in the developing of even more efficient transition metal oxides based photocatalysts.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Photocatalytic Activity of ZnO/CeO2 and ZnO/Yb2O3 Mixed Systems in the Phenol Removal from Water: A Mechanicistic Approach

Cerrato¹,

Gonçalves²,

Calza³

et al. 2020

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In this paper we compare the photocatalytic activity of two semiconductors based on ZnO: ZnO/CeO2 and ZnO/Yb2O3. The two samples were prepared via hydrothermal synthesis and fully characterized by X-ray diffraction technique, diffuse reflectance Ultra Violet- Visible spectroscopy (UV-Vis), high resolution transmission electron microscopy and finally with electron paramagnetic resonance spectroscopy. The prepared materials were also tested in their photocatalytic performances both through Electron Paramagnetic Resonance (EPR) analyzing the formation of charge carriers and with the abatement of a probe molecule like phenol, in presence and in absence of scavengers.

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Enhancing the photocatalytic efficiency of ZnO: Defects, heterojunction, and optimization

Cited by 59 publications

References 153 publications

A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

Photocatalytic, Bactericidal and Molecular Docking Analysis of Annealed Tin Oxide Nanostructures

Comparison of the Photocatalytic Activity of ZnO/CeO2 and ZnO/Yb2O3 Mixed Systems in the Phenol Removal from Water: A Mechanicistic Approach

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