scholarly journals Biomimetic Catalysts Based on Au@ZnO-Graphene Composites for the Generation of Hydrogen by Water Splitting

2020 ◽  
Author(s):  
Abniel Machín ◽  
Juan C Arango ◽  
Kenneth Fontánez ◽  
María Cotto ◽  
José Duconge ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Water Splitting ◽  
Zinc Oxide Nanoparticles ◽  
Fossil Fuels ◽  
High Photocatalytic Activity ◽  
Zno Nps ◽  
Oxide Nanowires ◽  
Biomimetic Catalysts ◽  
Natural Processes

For some decades, the scientific community has been looking for alternatives to the use of fossil fuels that allow the planet's sustainable and environmentally friendly development. To do this, attempts have been made to mimic some processes that occur in nature, among which the photosystem-II stands out, which allows water splitting operating with different steps to generate oxygen and hydrogen. This research presents promising results using synthetic catalysts, which try to simulate some natural processes, and which are based on Au@ZnO-graphene compounds. These catalysts were prepared by incorporating different amounts of gold nanoparticles (1 wt.%, 3 wt.%, 5 wt.%, 10 wt.%) and graphene (1 wt.%) on the surface of synthesized zinc oxide nanowires (ZnO NWs), and zinc oxide nanoparticles (ZnO NPs), along with a commercial form (commercial ZnO) for comparison purposes. The highest amount of hydrogen (1,127 µmol/hg) was reported by ZnO NWs with a gold and graphene loadings of 10 wt.% and 1 wt.%, respectively, under irradiation at 400 nm. Quantities of 759 µmol / hg and 709 µmol / hg were obtained with catalysts based on ZnO NPs and commercial ZnO, respectively. The photocatalytic activity of all composites increased with respect to the bare semiconductors, being 2.5 times higher in ZnO NWs, 8.8 times for ZnO NPs and 7.5 times for commercial ZnO. The high photocatalytic activity of the catalysts is attributed, mainly, to the synergism between the different amount of gold and graphene incorporated, and the surface area of the composites.

scholarly journals Biomimetic Catalysts Based on Au@ZnO–Graphene Composites for the Generation of Hydrogen by Water Splitting

Biomimetics ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 39
Author(s):  
Abniel Machín ◽  
Juan C. Arango ◽  
Kenneth Fontánez ◽  
María Cotto ◽  
José Duconge ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Water Splitting ◽  
Zinc Oxide Nanoparticles ◽  
Fossil Fuels ◽  
High Photocatalytic Activity ◽  
Zno Nps ◽  
Oxide Nanowires ◽  
Biomimetic Catalysts ◽  
Natural Processes

For some decades, the scientific community has been looking for alternatives to the use of fossil fuels that allow for the planet’s sustainable and environmentally-friendly development. To do this, attempts have been made to mimic some processes that occur in nature, among which the photosystem-II stands out, which allows water splitting operating with different steps to generate oxygen and hydrogen. This research presents promising results using synthetic catalysts, which try to simulate some natural processes, and which are based on Au@ZnO–graphene compounds. These catalysts were prepared by incorporating different amounts of gold nanoparticles (1 wt.%, 3 wt.%, 5 wt.%, 10 wt.%) and graphene (1 wt.%) on the surface of synthesized zinc oxide nanowires (ZnO NWs), and zinc oxide nanoparticles (ZnO NPs), along with a commercial form (commercial ZnO) for comparison purposes. The highest amount of hydrogen (1127 μmol/hg) was reported by ZnO NWs with a gold and graphene loadings of 10 wt.% and 1 wt.%, respectively, under irradiation at 400 nm. Quantities of 759 μmol/hg and 709 μmol/hg were obtained with catalysts based on ZnO NPs and commercial ZnO, respectively. The photocatalytic activity of all composites increased with respect to the bare semiconductors, being 2.5 times higher in ZnO NWs, 8.8 times higher for ZnO NPs, and 7.5 times higher for commercial ZnO. The high photocatalytic activity of the catalysts is attributed, mainly, to the synergism between the different amount of gold and graphene incorporated, and the surface area of the composites.

Evaluation of the Effect of Nanoparticles Zinc Oxide/Camellia sinensis Complex on the Kidney of Rats Treated with Monosodium Glutamate: Antioxidant and Histological Approaches

2019 ◽  
Vol 20 (7) ◽  
pp. 542-550 ◽  
Author(s):  
Nahla S. El-Shenawy ◽  
Reham Z. Hamza ◽  
Fawziah A. Al-Salmi ◽  
Rasha A. Al-Eisa
Keyword(s):  
Zinc Oxide ◽  
Camellia Sinensis ◽  
Zinc Oxide Nanoparticles ◽  
Morphological Changes ◽  
Monosodium Glutamate ◽  
Oxide Nanoparticles ◽  
High Dose ◽  
Enzymatic Antioxidants ◽  
Zno Nps ◽  
Tea Extract

Background: Zinc oxide nanoparticles (ZnO NPs) are robustly used biomedicine. Moreover, no study has been conducted to explore the consequence of green synthesis of ZnO NPs with Camellia sinensis (green tea extract, GTE) on kidneys of rats treated with monosodium glutamate (MSG). Methods: Therefore, the objective of the research was designed to explore the possible defensive effect of GTE/ZnO NPs against MSG-induced renal stress investigated at redox and histopathological points. Results: The levels of urea and creatinine increased as the effect of a high dose of MSG, in addition, the myeloperoxidase and xanthine oxidase activates were elevated significantly with the high dose of MSG. The levels of non-enzymatic antioxidants (uric acid, glutathione, and thiol) were decreased sharply in MSG-treated rats as compared to the normal group. Conclusion: The data displayed that GTE/ZnO NPs reduced the effects of MSG significantly by reduction of the level peroxidation and enhancement intracellular antioxidant. These biochemical findings were supported by histopathology evaluation, which showed minor morphological changes in the kidneys of rats.

Zinc oxide nanoparticles help to enhance plant growth and alleviate abiotic stress: A review

2020 ◽  
Vol 21 ◽  
Author(s):  
Mohammad Faizan ◽  
Fangyuan Yu ◽  
Chen Chen ◽  
Ahmad Faraz ◽  
Shamsul Hayat
Keyword(s):  
Zinc Oxide ◽  
Plant Growth ◽  
Abiotic Stresses ◽  
Zinc Oxide Nanoparticles ◽  
Growth And Yield ◽  
Oxide Nanoparticles ◽  
Main Concern ◽  
Negative Effects ◽  
Zno Nps ◽  
Agricultural Yield

: Abiotic stresses arising from atmosphere change belie plant growth and yield, leading to food reduction. The cultivation of a large number of crops in the contaminated environment is a main concern of environmentalists in the present time. To get food safety, a highly developed nanotechnology is a useful tool for promoting food production and assuring sustainability. Nanotechnology helps to better production in agriculture by promoting the efficiency of inputs and reducing relevant losses. This review examines the research performed in the past to show how zinc oxide nanoparticles (ZnO-NPs) are influencing the negative effects of abiotic stresses. Application of ZnO-NPs is one of the most effectual options for considerable enhancement of agricultural yield globally under stressful conditions. ZnO-NPs can transform the agricultural and food industry with the help of several innovative tools in reversing oxidative stress symptoms induced by abiotic stresses. In addition, the effect of ZnO-NPs on physiological, biochemical, and antioxidative activities in various plants have also been examined properly. This review summarizes the current understanding and the future possibilities of plant-ZnO-NPs research.

scholarly journals Wound Healing Composite Materials of Bacterial Cellulose and Zinc Oxide Nanoparticles with Immobilized Betulin Diphosphate

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 713
Author(s):  
Nina Melnikova ◽  
Alexander Knyazev ◽  
Viktor Nikolskiy ◽  
Peter Peretyagin ◽  
Kseniia Belyaeva ◽  
...  
Keyword(s):  
Wound Healing ◽  
Zinc Oxide ◽  
Bacterial Cellulose ◽  
Zinc Oxide Nanoparticles ◽  
Wound Dressings ◽  
Oxide Nanoparticles ◽  
Burn Wound ◽  
Zno Nps ◽  
Wound Model ◽  
And Oxidative Stress

A design of new nanocomposites of bacterial cellulose (BC) and betulin diphosphate (BDP) pre-impregnated into the surface of zinc oxide nanoparticles (ZnO NPs) for the production of wound dressings is proposed. The sizes of crystalline BC and ZnO NPs (5–25%) corresponded to 5–6 nm and 10–18 nm, respectively (powder X-ray diffractometry (PXRD), Fourier-infrared (FTIR), ultraviolet (UV), atomic absorption (AAS) and photoluminescence (PL) spectroscopies). The biological activity of the wound dressings “BC-ZnO NPs-BDP” was investigated in rats using a burn wound model. Morpho-histological studies have shown that more intensive healing was observed during treatment with hydrophilic nanocomposites than the oleophilic standard (ZnO NPs-BDP oleogel; p < 0.001). Treatment by both hydrophilic and lipophilic agents led to increases in antioxidant enzyme activity (superoxide dismutase (SOD), catalase) in erythrocytes and decreases in the malondialdehyde (MDA) concentration by 7, 10 and 21 days (p < 0.001). The microcirculation index was restored on the 3rd day after burn under treatment with BC-ZnO NPs-BDP wound dressings. The results of effective wound healing with BC-ZnO NPs-BDP nanocomposites can be explained by the synergistic effect of all nanocomposite components, which regulate oxygenation and microcirculation, reducing hypoxia and oxidative stress in a burn wound.

scholarly journals Biosynthesis of Zinc Oxide Nanoparticles from Acacia nilotica (L.) Extract to Overcome Carbapenem-Resistant Klebsiella Pneumoniae

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1919
Author(s):  
Elsayim Rasha ◽  
AlOthman Monerah ◽  
Alkhulaifi Manal ◽  
Ali Rehab ◽  
Doud Mohammed ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Klebsiella Pneumoniae ◽  
Zinc Oxide Nanoparticles ◽  
Acacia Nilotica ◽  
Oxide Nanoparticles ◽  
Zno Nps ◽  
X Ray ◽  
Carbapenem Resistant

Recently, concerns have been raised globally about antimicrobial resistance, the prevalence of which has increased significantly. Carbapenem-resistant Klebsiella pneumoniae (KPC) is considered one of the most common resistant bacteria, which has spread to ICUs in Saudi Arabia. This study was established to investigate the antibacterial activity of biosynthesized zinc oxide nanoparticles (ZnO-NPs) against KPC in vitro and in vivo. In this study, we used the aqueous extract of Acacia nilotica (L.) fruits to mediate the synthesis of ZnO-NPs. The nanoparticles produced were characterized by UV-vis spectroscopy, zetasizer and zeta potential analyses, X-ray diffraction (XRD) spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The antimicrobial activity of ZnO-NPs against KPC was determined via the well diffusion method, and determining minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), the results showed low MIC and MBC when compared with the MIC and MBC of Imipenem and Meropenem antibiotics. The results of in vitro analysis were supported by the results upon applying ZnO-NP ointment to promote wound closure of rats, which showed better wound healing than the results with imipenem ointment. The biosynthesized ZnO-NPs showed good potential for use against bacteria due to their small size, applicability, and low toxicity to human cells.

scholarly journals Scolicidal activity of biosynthesized zinc oxide nanoparticles by Mentha longifolia L. leaves against Echinococcus granulosus protoscolices

2021 ◽  
Author(s):  
Bushra H. Shnawa ◽  
Samir M. Hamad ◽  
Azeez A. Barzinjy ◽  
Payman A. Kareem ◽  
Mukhtar H. Ahmed
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Public Health Problem ◽  
Analytical Techniques ◽  
Oxide Nanoparticles ◽  
Zno Nps ◽  
Leaf Extracts ◽  
X Ray ◽  
Morphological Alterations ◽  
Mentha Longifolia

AbstractCystic echinococcosis is a public health problem in developing countries that practice sheep breeding extensively. In the current study, the protoscolicidal activity of biosynthesized zinc oxide nanoparticles (ZnO NPs) derived from Mentha longifolia L. leaf extracts was investigated. The resultant ZnO NPs were characterized by means of various analytical techniques, such as ultraviolet–visible (UV–Vis) spectrometry, Fourier transform infrared (FT-IR) spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The results showed that the ZnO NP had the highest scolicidal activity at 400 ppm concentration after 150 min of exposure time, showing 100% mortality rate. The treated protoscolices exhibited loss of viability with several morphological alterations. Hence, an easy and effective green synthesis of ZnO NPs, with efficient scolicidal potential, is reported in this study.

scholarly journals Zinc oxide nanoparticles using plant Lawsonia inermis and their mosquitocidal, antimicrobial, anticancer applications showing moderate side effects

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pandiyan Amuthavalli ◽  
Jiang-Shiou Hwang ◽  
Hans-Uwe Dahms ◽  
Lan Wang ◽  
Jagannathan Anitha ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Mosquito Control ◽  
Xrd Analysis ◽  
Microbial Pathogens ◽  
Oxide Nanoparticles ◽  
Lawsonia Inermis ◽  
Zno Nps ◽  
Vector Borne Diseases ◽  
Substantial Problem

AbstractMicrobes or parasites spread vector-borne diseases by mosquitoes without being affected themselves. Insecticides used in vector control produce a substantial problem for human health. This study synthesized zinc oxide nanoparticles (ZnO NPs) using Lawsonia inermis L. and were characterized by UV–vis, FT-IR, SEM with EDX, and XRD analysis. Green synthesized ZnO NPs were highly toxic against Anopheles stephensi, whose lethal concentrations values ranged from 5.494 ppm (I instar), 6.801 ppm (II instar), 9.336 ppm (III instar), 10.736 ppm (IV instar), and 12.710 ppm (pupae) in contrast to L. inermis treatment. The predation efficiency of the teleost fish Gambusia affinis and the copepod Mesocyclops aspericornis against A. stephensi was not affected by exposure at sublethal doses of ZnO NPs. The predatory potency for G. affinis was 45 (I) and 25.83% (IV), copepod M. aspericornis was 40.66 (I) and 10.8% (IV) while in an ZnO NPs contaminated environment, the predation by the fish G. affinis was boosted to 71.33 and 34.25%, and predation of the copepod M. aspericornis was 60.35 and 16.75%, respectively. ZnO NPs inhibited the growth of several microbial pathogens including the bacteria (Escherichia coli and Bacillus subtilis) and the fungi (Alternaria alternate and Aspergillus flavus), respectively. ZnO NPs decreased the cell viability of Hep-G2 with IC50 value of 21.63 µg/mL (R2 = 0.942; P < 0.001) while the concentration increased from 1.88 to 30 µg/mL. These outcomes support the use of L. inermis mediated ZnO NPs for mosquito control and drug development.

scholarly journals Biomimetic Synthesis, Characterization, and Evaluation of Fluorescence Resonance Energy Transfer, Photoluminescence, and Photocatalytic Activity of Zinc Oxide Nanoparticles

2021 ◽  
Vol 13 (4) ◽  
pp. 2004
Author(s):  
Udari Wijesinghe ◽  
Gobika Thiripuranathar ◽  
Haroon Iqbal ◽  
Farid Menaa
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Photocatalytic Activity ◽  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Solar Irradiation ◽  
Zno Nps ◽  
Fluorescence Resonance

Owing to the development of nanotechnology, biosynthesis of nanoparticles (NPs) is gaining considerable attention as a cost-effective and eco-friendly approach that minimizes the effects of toxic chemicals used in NP fabrication. The present work reports low-cost phytofabrication of zinc oxide (ZnO) NPs employing aqueous extracts of various parts (leaves, stems, and inflorescences) of Tephrosia purpurea (T. purpurea). The formation, structure, morphology, and other physicochemical properties of ZnO NPs were characterized by ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS). UV–Vis spectral analysis revealed sharp surface plasmon resonance (SPR) at around 250–280 nm, while the XRD patterns confirmed distinctive peaks indices to the crystalline planes of hexagonal wurtzite ZnO NPs. TEM analysis confirmed the presence of spherical-shaped ZnO NPs with average particle sizes (PS) between 25–35 nm, which was in agreement with the XRD results. FTIR analysis revealed that phenolics, flavonoids, amides, alkaloids, and amines present in the plant extract are responsible for the stabilization of the ZnO NPs. Further, the hydrodynamic diameter in the range of 85–150 nm was measured using the DLS technique. The fluorescence resonance energy transfer (FRET) ability of biogenic ZnO NPs was evaluated, and the highest efficiency was found in ZnO NPs synthesized via T. purpurea inflorescences extract. Photoluminescence (PL) spectra of biogenic ZnO NPs showed three emission peaks consisting of a UV–Vis region with high-intensity compared to that of chemically synthesized ZnO NPs. The biosynthesized ZnO NPs showed photocatalytic activity under solar irradiation by enhancing the degradation rate of methylene blue (MB). Among the prepared biogenic ZnO NPs, T. purpurea leaves mediated with NPs acted as the most effective photocatalyst, with a maximum degradation efficiency of 98.86% and a half-life of 84.7 min. This is the first report related to the synthesis of multifunctional ZnO NPs using T. purpurea, with interesting characteristics for various potential applications in the future.

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