Bulk Zinc Oxide Research Articles

Foliar Application of Zn Agrichemicals Affects the Bioavailability of Arsenic, Cadmium and Micronutrients to Rice (Oryza sativa L.) in Flooded Paddy Soil

Zinc (Zn) is a key micronutrient affecting bio-functions of crops. Impacts of foliar application of three forms of Zn-containing agrichemicals on the physiology of rice seedlings and their uptake of heavy metal(loid)s and micronutrients from fully flooded paddy soils were investigated in a greenhouse study. Rice seedlings 45 days after germination were randomly exposed to an equivalent amount of 100 mg L−1 of zinc oxide nanoparticles (ZnONPs), zinc oxide bulk particles (ZnOBPs), and zinc salts (Zn2+) through foliar exposure. At termination, rice seedlings were divided into roots and shoots and the concerned metal contents in plant tissues were determined with an inductively coupled plasma mass spectrometry (ICP-MS). Our results demonstrated that all Zn agrichemicals displayed a similar effect on plant growth, but ZnONPs led to the greatest root exudate excretion and greatest inhibition in arsenic (As) uptake. Foliar application of ZnONPs resulted in 28% less As in rice shoots while Zn2+ only caused a 15% decrease in As accumulation in the same tissues. ZnOBPs had minimal impact on As concentration in rice shoots. ZnONPs also promoted iron (Fe) and copper (Cu) uptake in rice shoots, both of which are essential micronutrients for humans. The results suggest that foliar application of ZnONPs resulted in more favorable outcomes for plant growth and food safety than other two types of Zn. Overall, our results showed that application of nanoagrichemicals have important food safety and nutrition implications in addition to their agronomical roles and ZnONPs could be potentially used to alleviate As uptake and fortify Zn and other essential micronutrients in rice grains.

Hydrophobic Surface Coating Can Reduce Toxicity of Zinc Oxide Nanoparticles to the Marine Copepod Tigriopus japonicus.

Coated zinc oxide nanoparticles (ZnO-NPs) are more commonly applied in commercial products but current risk assessments mostly focus on bare ZnO-NPs. To investigate the impacts of surface coatings, this study examined acute and chronic toxicities of six chemicals, including bare ZnO-NPs, ZnO-NPs with three silane coatings of different hydrophobicity, zinc oxide bulk particles (ZnO-BKs), and zinc ions (Zn-IONs), toward a marine copepod, Tigriopus japonicus. In acute tests, bare ZnO-NPs and hydrophobic ZnO-NPs were less toxic than hydrophilic ZnO-NPs. Analyses of the copepod's antioxidant gene expression suggested that such differences were governed by hydrodynamic size and ion dissolution of the particles, which affected zinc bioaccumulation in copepods. Conversely, all test particles, except the least toxic hydrophobic ZnO-NPs, shared similar chronic toxicity as Zn-IONs because they mostly dissolved into zinc ions at low test concentrations. The metadata analysis, together with our test results, further suggested that the toxicity of coated metal-associated nanoparticles could be predicted by the hydrophobicity and density of their surface coatings. This study evidenced the influence of surface coatings on the physicochemical properties, toxicity, and toxic mechanisms of ZnO-NPs and provided insights into the toxicity prediction of coated nanoparticles from their coating properties to improve their future risk assessment and management.

Seed Priming and Coating by Nano-Scale Zinc Oxide Particles Improved Vegetative Growth, Yield and Quality of Fodder Maize (Zea mays)

Nano-fertilizers of essential plant nutrients, including micronutrients, have the potential to improve nutrient use efficiency and productivity of field crops in deficient soils. The present study reports the comparative influence of zinc oxide nanoparticles (ZnONPs) and bulk Zn salt (ZnSO4) on the growth, yield, and quality of fodder maize (Zea mays) (var. J-1006) cultivated under field conditions in the year 2019. Three levels (0, 20, and 40 mg L−1) of Zn fertilizers were used for seed priming and coating in triplicate following the randomized complete block design model. An increase in vegetative and yield parameters (number of plants, plant height, stover yield, plant biomass), acid detergent fiber (ADF%), and hemicellulose contents and shoot zinc (Zn) content on treatment of seeds with ZnONPs (20 mg L−1) concentration as compared to bulk ZnSO4 and control treatments was observed. The application of ZnONPs (40 mg L−1) significantly enhanced the total chlorophyll content, available soil nitrogen and phosphorus, neutral detergent fiber (NDF%), and cellulose contents and improved the total soil microbial counts and soil enzyme activities (dehydrogenase, acid and alkaline phosphatase enzyme activities), whereas a significant increase in available soil potassium and zinc contents was recorded under ZnONPs (20 mg L−1) treatments. These findings suggest an encouraging effect on the growth and yield attributing characteristics of fodder maize after ZnONPs seed coating at low concentration. Furthermore, ZnONPs seed coating can also be considered an effective tool for the delivery of Zn micronutrient to fodder maize crop.

Zinc oxide nanoparticles mediated substantial physiological and molecular changes in tomato.

There has long been debate about how nanoproducts meet agricultural requirements. This study aimed to investigate tomato responses to the long-time foliar application of zinc oxide nanoparticles (ZnO-NP; 0 and 3 mgl-1) or bulk type (BZnO). Both ZnO-NP and BZnO treatments, especially the nanoform, were significantly capable of improving growth, biomass, and yield. The ZnO-NP treatment upregulated the expression of the R2R3MYB transcription factor by 2.6 folds. The BZnO and ZnO-NP treatments transcriptionally up-regulated WRKY1 gene by 2.5 and 6.4 folds, respectively. The bHLH gene was also upregulated in response to BZnO (2.3-fold) or ZnO-NP (4.7-fold). Moreover, the ZnO-NP application made a contribution to upregulation in the EREB gene whereas the bulk compound did not make a significant change. Upregulation in the HsfA1a gene also resulted from the ZnO-NP (2.8-fold) or BZnO (1.6-fold) supplementation. The MKK2 and CAT genes displayed a similar upregulation trend in response to the supplements by an average of 3-folds. While the application of ZnO-NP slightly down-regulated the histone deacetylases (HDA3) gene by 1.9-fold, indicating epigenetic modification. The supplements, especially the nano-product, enhanced concentrations of K, Fe, and Zn in both leaves and fruits. The concentrations of Chla, Chlb, and carotenoids were increased in response to the BZnO or ZnO-NP treatments. Likewise, BZnO or ZnO-NP mediated an increase in activity of nitrate reductase and proline content in leaves. These treatments increased soluble phenols and phenylalanine ammonia-lyase activity. With a similar trend, the BZnO or ZnO-NP application improved the activities of catalase and peroxidase enzymes. The reinforcement in metaxylem and secondary tissues resulted from the applied supplements. This study provides comprehensive comparative evidence on how ZnO-NPs may remodel the chromatin ultrastructure and transcription program, and confer stress tolerance in crops. This study also underlines the necessity of providing integrated transcriptome and proteome data in future studies.

Band Gap Narrowing in Silane-Grafted ZnO Nanocrystals. A Comprehensive Study by Wide-Angle X-ray Total Scattering Methods

Zinc oxide (ZnO) is a largely investigated semiconducting nanomaterial for photocatalytic applications and is an excellent active layer candidate in photovoltaics. Among native defects, having a primary role in ZnO optoelectronic properties, the influence of nearly ubiquitous planar faults of wurtzite sequences in ultrasmall (≤5 nm) nanocrystals (NCs) remains poorly understood. Here, we present a thorough study of ZnO NCs prepared under morphological control of covalently grafted vinyltrimethoxysilane (VTMS) and exhibiting either narrowing or widening of the band gap upon NCs downsizing, depending on the NC growth rate. By using synchrotron X-ray total scattering data, atomistic models and the Debye Scattering Equation (DSE) method, complemented by spectroscopic (FTIR and UV–vis) investigations, we provide a comprehensive quantitative picture in which effects from planar defects are disentangled from those due to NC size, morphology, and lattice strain (here controlled by preferential binding of VTMS on the ZnO basal faces). When faults occur in high concentration (linear density up to 1.6 × 10⁶ cm–¹), NCs exhibit optical band gap narrowing (3.27 eV vs 3.37 eV in bulk ZnO), whereas gap widening (3.52 eV) is observed at a lower density (0.8 × 10⁶ cm–¹), at which quantum-size confinement effects prevail. Supported by photoluminescence and photodegradation experiments, surface defect passivation by VTMS, affecting visible emissions and photocatalytic properties of ZnO, is also discussed in relation to silane coating and fault-driven bandgap. This work sheds light on the complex interplay among planar defects, quantum size effect, and surface modifications in ultrasmall ZnO NCs and on the importance of advanced X-ray total scattering methods toward atomically precise control of defects in nanostructures.

ZnO for stable and efficient perovskite bulk heterojunction solar cell fabricated under ambient atmosphere

In the present paper, we report the studies on perovskite (CH3NH3PbI3): Zinc Oxide (ZnO) bulk heterojunction (BHJ) photoactive layer (with two different ZnO concentrations) based solar cells fabricated under ambient air. ZnO and NiOx layers are used as the electron and hole transport layers respectively. The typical cell parameters of CH3NH3PbI3: ZnO BHJ solar cells have been calculated and analysed in comparison to that of solar cell fabricated with pristine perovskite (CH3NH3PbI3) based photoactive layer. The best performing solar cell (CH3NH3PbI3:ZnO; 1 mg/ml) has demonstrated highest power conversion efficiency (PCE) of 8.97% and retained 83.82% of its original value after 30 days under ambient air.

Zinc Silicate Thin Film Composites Obtained by a Sputtering Based Approach: Structural, Dielectric and Photovoltaic Properties

This study deals with the production of zinc silicate thin films employing a solid-state reaction at temperatures ranging from 300 °C to 560 °C, to develop new inorganic, n-type materials with seemingly incompatible properties as low work function, high mobility, and high visible transmittance. Depending on a careful reaction control, zinc silicates can preserve reagents (silicon and/or ZnO) as nanoaggregate guests, exhibiting tunable light absorption and emission properties that make them useful for different applications, e.g., LED phosphors, photovoltaic windows, mesoporous photocatalytic materials for solar fuel production, etc. The main aim of this work is to obtain a zinc silicate single-phase and then determine its dielectric properties through ellipsometry. Simultaneously, as an example of application, a p-n photovoltaic junction is fabricated that exhibits a remarkable collection of photo-generated charge carriers at very high bandgaps (>2 eV). The obtained results are promising in tailoring the zinc silicate guest-host composition (appropriate Si nanostructures sizing and quantity, improved charge carrier transport properties due to the simultaneous presence of bulk zinc oxide islands) in the function of the desired application, and taking into account that proposed selected low-temperature fabrication process is strategic for safeguarding the underlying junctions of tandem devices.

Maximum piezoelectricity in a few unit-cell thick planar ZnO – A liquid metal-based synthesis approach

Synthesizing two dimensional (2D) nanomaterials with controlled sub-nanometer thicknesses from non-layered crystals presents both significant challenges and vast opportunities. However, mechanical exfoliation techniques and physical/wet chemical deposition processes are widely disadvantageous for applicability to non-layered structures. Here we have utilized a simple self-limiting approach to prepare large sheets of 2D zinc oxide (ZnO) at the metal-melt/air interface. These ultra-thin sheets demonstrated highly crystalline hexagonal structures. The specific ZnO hexagonal sheet thickness and its interaction with the substrate were found to have a critical impact on d33. This unusual structure resulted in an exceptionally high out of plane piezoelectricity, yielding a giant value of 80 ± 0.8 pm/V at 2.5 unit-cell thickness for d33, which is 5 Zn-O layers in the wurtzite crystal. This out of plane piezoelectricity value is approximately 8 times larger than that of the value for bulk ZnO. Theoretical studies were carried out to elucidate the impact of the thickness and the substrate’s role on the polarization of the layers. The existence of a large piezoelectricity offered by the synergy of the substrate and specific thickness of ultrathin films offers the opportunity for other groups of potentially piezoelectric materials to be explored.

Core-shell nanostructured Zn-Co-O@CoS arrays for high-performance hybrid supercapacitors.

Although zinc oxide (ZnO) with wide distribution is one of the most attractive energy storage materials, the low electronic conductivity and insufficient active sites of bulk ZnO increase the internal resistance and reduce the capacity of electrodes for supercapacitors. Herein, CoS nanosheets are coated on the surface of heterostructured ZnO/Co3O4 nanowires to synthesize a core-shell Zn-Co-O@CoS electrode by a three-step method. The built-in electric field formed between ZnO and Co3O4 can enhance the conductivity of the composite electrode. The coating of amorphous CoS can also provide sufficient active sites and improve the chemical stability of ZnO/Co3O4 nanowires. As a result, the as-prepared Zn-Co-O@CoS electrode delivers a high specific capacity of 1190 C g-1, which is 7 times higher than that of the pristine ZnO electrode. Besides, a hybrid supercapacitor (HSC) with the Zn-Co-O@CoS electrode exhibits a high energy density of 56.8 W h kg-1 at a power density of 771.6 W kg-1. Furthermore, we assembled a solar-charging power system by combining the HSC and monocrystalline silicon plates to prove the practicability of the device, which can power a toy electric fan successfully. This study provides an effective idea and strategy for preparing Zn-based supercapacitor electrodes with low cost and deep discharge.

Studies of Zinc and Zinc Oxide Nanofilms of Different Thickness Prepared by Magnetron Sputtering and Thermal Oxidation-=SUP=-*-=/SUP=-

Polycrystalline zinc films with the thickness of about 20, 40, 60, and 80 nm and mainly granular morphology comprising nearly spherical particles involving hexagonal crystals are obtained by magnetron sputtering on cover glass supports. Subsequently, the prepared layers were subjected to thermal oxidation in the air to obtain transparent zinc oxide layers. The synthesized films are studied by SEM and UV-vis spectroscopy. Based on the obtained spectra, optical properties of the layers are studied as a function of their thickness. The optical band gap Eg for the films with the thickness from 40 to 80 nm is estimated on the level about 3.28 eV similar to the reference value 3.3 eV for bulk zinc oxide, while for the thickness of 20 nm Eg slightly drops to about 3.24 eV. Keywords: zinc; zinc oxide; nanolayers; magnetron; oxidation; surface morphology; transparency; optical bandgap.

Insight Study on the Comparison between Zinc Oxide Nanoparticles and Its Bulk Impact on Reproductive Performance, Antioxidant Levels, Gene Expression, and Histopathology of Testes in Male Rats.

Background: Despite the beneficial effects of zinc oxide nanoparticles (ZnONPs) on different biomedical applications, including their antioxidant and anti-inflammatory ones, it might have cytotoxic and genotoxic impacts on the male reproductive system. Objective: The current study compares the effect of zinc oxide nanoparticles and their bulk form, at different doses, on male rats’ reproductive performance, testicular antioxidants, gene expression, and histopathology. Materials and Methods: Thirty male rats were randomly allocated equally in five groups. The control one was injected with Tween 80 (10%). The zinc oxide nanoparticle (ZnONP) groups received ZnONPs < 50 nm, specifically, 5 mg/kg (ZnONP-1) and 10 mg/kg (ZnONP-2). The bulk zinc oxide (BZnO) groups were administered 5 mg/kg (BZnO-1) and 10 mg/kg (BZnO-2), correspondingly. Rats were injected intraperitoneally with the respected materials, twice/week for eight consecutive weeks. Finally, the male rats’ sexual behavior and their pup’s performance were determined in a monogamous mating system. Rats were then anesthetized and sacrificed for semen characteristics evaluation and tissue collection for antioxidant and hormones analysis, gene expression, and histopathological examination. Results: It was shown that ZnONP-1 improved sexual behavior, semen characteristics, and pup’s performance compared to its bulk form. Similarly, the testicular antioxidants activity, glutathione (GSH), and superoxide dismutase (SOD) increased with a decrease in the malonaldehyde (MDA), interleukin 6 (IL-6), and tumor necrosis factor (TNF-α) levels. It also improves the reproductive hormone levels and mRNA expression of different steroidogenesis-associated genes and anti-apoptotic genes. Conclusion: It can be concluded that zinc oxide nanoparticles, administered at 5 mg/kg, had the most beneficial effect on male reproductive performance, while 10 mg/kg could have a detrimental effect.

Modeling the Physical Properties of ZnO Nanoparticles with Selective Hydrogen Using DFT

The impact of hydrogen on the conductivity and vibration for zinc oxide (ZnO) nanoparticles had implicated for nanoscale optoelectronic units. Infrared reflectance spectra for ZnO hydrogen-annealed nanoparticles were calculated at incidence. The theory of density functional theory is applied to the reflectance model and absorption spectra. There is an agreement between both the model suggesting that the nanoparticles have inhomogeneous carriers’ concentrations and the experimental results. A significant decrease in carrier concentration resulted from exposure to oxygen for several hours, according to the adsorption on the nanoparticle surface of negative oxygen molecules. Also, the density of states in deferent wurtzoid’s size has been studied. The experimental energy gap values of bulk ZnO, HOMO and LUMO levels as a function of the total Zn and O atoms number in ZnOH diamondoids were determined, as well as the bond length in deferent wurtzoid’s size where the experimental ZnO bond length at 1.9767 Å has been calculated. The tetrahedral angles in deferent wurtzoid’s size were studied, deferent wurtzoid’s size Reduced mass as a vibration frequency function and force constant as a function of vibrational frequency in deferent wurtzoid’s size were determined. A good result for infrared as a vibration frequency function in deferent wurtzoid’s size has been found, as well as Raman as a vibration frequency function in deferent wurtzoid’s size.

A comparative study on thermoelectric properties of ZnO bulks and thin films

Introduction: Zinc oxide (ZnO) is well-known as a promising thermoelectric material owing to its safety, inexpensiveness, and thermal stability. This research provides an overview of thermoelectric potentials, including structure, electrical conductivity, Seebeck coefficient, and power factor of pure ZnO semiconductor synthesized in bulk and thin-film forms.&#x0D; Methods: The ZnO bulk was synthesized by solid-state reaction at high temperature, while the thin film was prepared by d.c. magnetron sputtering technique. The temperature-dependent thermoelectric properties of all the samples were measured by the Seebeck LSR-3 system. The crystallographic and surface morphological information of the samples were obtained by using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively.&#x0D; Results: The XRD results confirm that both the bulk and thin-film have polycrystalline structure and characteristics of hexagonal-wurtzite ZnO. Through the FESEM observation, the bulk is well densified under high-temperature condition, while the thin-film achieve good orientation and close-packed grains. At 573 K, the obtained thermoelectric properties (electrical conductivity, Seebeck coefficient, and power factor) are respectively 352.4 S/cm, -89.5 µV/K and 282.5 µW/mK2 for the ZnO bulk; and 289 S/cm, -113.8 µV/K and 374.3 µW/mK2 for the ZnO film.&#x0D; Conclusion: The comparative study shows the good thermoelectric potential of ZnO material in both forms of bulk and thin film. Among them, the thin film has better results, especially in the Seebeck coefficient and power factor than one.

Food grade zinc oxide bulk particle composite can replace the toxic zinc oxide nano composite towards the control of pathogenic and spoilage bacteria.

ZnO-Nanoparticle-Chitosan (ZnO-NP-CH) composite has potential biomedical and food applications due to its better antimicrobial activity. However, the presence of nano-metal-oxide in the composite makes the material unsuitable for any food applications. Moreover, the cost involved in the preparation of Zinc Oxide-Nano-Particle (ZnO-NP) is a major limitation for commercial food applications. Hence a suitable alternative for ZnO-NP is highly needed for food application. Since ZnO-Bulk Particles (ZnO-BP) are food grade and there is no study on the composite prepared from ZnO-Bulk Particle-Chitosan (ZnO-BP-CH), in the present study, antimicrobial activity was assessed for ZnO-BP-CH and compared with ZnO-NP-CH. Based on the study, it was observed that in the individual form of ZnO-NP possessed significantly higher antimicrobial activity than ZnO-BP. The composite form of ZnO-NP-CH and ZnO-BP-CH possessed higher antimicrobial activity than chitosan. However, no significant difference was observed between the composite forms. Hence, ZnO-BP-CH could be recommended as a suitable alternative to ZnO-NP-CH for future studies related to chitosan with ZnO composite to avoid costly nanomaterials preparation.

Ameliorative effect of vitamins (E and C) on biochemical alterations induced by sublethal concentrations of zinc oxide bulk and nanoparticles in Oreochromis niloticus

The comparison between bulk and nano ZnO particles were antecedently studied but describing the dose-dependent toxicity and the ameliorative effect of vitamins (E and C) in Oreochromis niloticus, have not been previously documented. Therefore, the present study was designed to investigate the ameliorative effect of vitamins (E and C) against oxidative stress and biochemical alterations induced by sublethal concentrations of zinc oxide bulk particles (ZnOBPs) and zinc oxide nanoparticles (ZnONPs). Toxicity tests were carried out on O. niloticus and showed that 96 h LC50 values of ZnOBPs and ZnONPs were 84 mg/l and 5.6 mg/l respectively. Exposure of the studied fish to these sublethel concentrations for 7, 14, 21 & 28 days showed a significant increase (p < 0.05) in serum glucose, AST, ALT, creatinine, urea and uric acid compared to control groups while, fish groups exposed to ZnOBPs or ZnONPs and supplemented with vitamins E and C, their serum enzyme concentrations were decreased compared to the groups without supplementation after 7, 14, 21 and 28 day. On the other hand, antioxidant defense enzymes (SOD, CAT and GST) activity in O.niloticus fish were increased significantly (p < 0.05) when exposed to sublethal concentrations of ZnOBPs or ZnONPs compared to the control value. However, fish groups supplemented with vitamins (E and C) have a decrease in SOD, CAT and GST enzymes activity when compared to unsupplemented groups and the values returned to similar levels established in the control at low concentrations but still higher than control at the high concentrations.

Impacts of zinc oxide nano and bulk particles on redox-enzymes of the Punica granatum callus

The structure and function of cellular membranes were sustained by redox-enzymes. We studied the interaction between the oxidative stress caused by excessive accumulation of ZnO-nanoparticles (ZnO-NPs) in plants and the role of redox-enzymes that can alleviate this stress. The crude callus extract from pomegranate, which was treated with 0, 10, and 150 µg mL−1 ZnO-NPs or bulk particles (ZnO-BPs), was applied to study the activity and kinetics of redox-enzymes. The elevated ZnO-NPs, enhanced the lipoxygenase and polyphenol oxidase activity, while the ZnO-BPs did not modify them. The activities of superoxide dismutase, catalase, and phenylalanine ammonia-lyase were induced under ZnO-NPs or BPs treatments, whilst the opposite trend of peroxidase was observed. Ascorbate peroxidase activity increased under ZnO-NPs treatments but decreased under ZnO-BPs. The kinetics activity of enzymes showed changes under different levels of NPs and BPs. Additionally, NPs or BPs treatments reduced the uptake of copper, iron, magnesium, but increased zinc accumulation in callus tissues. Meanwhile, these treatments enhanced the accumulation of manganese ions but did not affect the accumulation of potassium and phosphorous in ZnO-NPs or BPs-stressed calli. Collectively, these results gave a quantitative evaluation of the competition of zinc and other minerals on the carriers, and in addition, they provided a basis for how to control ZnO-NPs or BPs toxicity via redox-enzymes.

Biosynthesis of ZnO Nanostructures Using Azadirachta indica Leaf Extract and Their Effect on Seed Germination and Seedling Growth of Tomato: An Eco-Friendly Approach

In this study, we report synthesis of Zinc oxide nanoparticles using simple chemical and green methods. The ZnO nanoparticles were synthesized using leaf extract of Azadirachta indica (neem) as reducing agent. The as obtained product was characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray analysis (EDAX) and TEM techniques. XRD analysis confirms that ZnO nanoparticles were crystalline having hexagonal Wurtzite structure with (1 0 0), (0 0 2), (1 0 1), (1 0 2), (1 1 0) and (1 1 2) planes. SEM analyses show that the as synthesized ZnO NPs were in the form of agglomerates and no other impurity peak was found in the EDS. TEM analyses confirm that the size of the nanoparticle was approx. 50 nm. Here in, we investigate the effect of chemical and green synthesized zinc oxide nanoparticles on germination and growth of lycopersicum esculentus (tomato) using petri plate seed germination method in loamy sand soil. The impact of concentration of applied ZnO nanoparticles via green synthesis and chemical methods were analyzed. Results revealed that green synthesized Zinc oxide nanoparticles showed maximum growth of seedling as compared to chemically synthesized Zinc oxide nanoparticles, bulk ZnO and control. After 50 days of tomato growth analysis, it was recognized that ZnO NPs can be a good green synthetic fertilizer by increasing shoot length, wet weight, dry weight and yield over conventional control. Hence, green method is found to be more effective.

Metformin-Templated Nanoporous ZnO and Covalent Organic Framework Heterojunction Photoanode for Photoelectrochemical Water Oxidation.

Photoelectrochemical water-splitting offers unique opportunity in the utilization of abundant solar light energy and water resources to produce hydrogen (renewable energy) and oxygen (clean environment) in the presence of a semiconductor photoanode. Zinc oxide (ZnO), a wide bandgap semiconductor is found to crystallize predominantly in the hexagonal wurtzite phase. Herein, we first report a new crystalline triclinic phase of ZnO by using N-rich antidiabetic drug metformin as a template via hydrothermal synthesis with self-assembled nanorod-like particle morphology. We have fabricated a heterojunction nanocomposite charge carrier photoanode by coupling this porous ZnO with a covalent organic framework, which displayed highly enhanced photocurrent density of 0.62 mA/cm2 at 0.2 V vs. RHE in photoelectrochemical water oxidation and excellent photon-to-current conversion efficiency at near-neutral pH vis-à-vis bulk ZnO. This enhancement of the photocurrent for the porous ZnO/COF nanocomposite material over the corresponding bulk ZnO could be attributed to the visible light energy absorption by COF and subsequent efficient charge-carrier mobility via porous ZnO surface.

Analytical approach to phonon calculations in the SCC-DFTB framework

Detailed derivation of the analytical, reciprocal-space approach of Hessian calculation within the self-consistent-charge density-functional based tight-binding framework (SCC-DFTB) is presented. This approach provides an accurate and efficient way for obtaining the SCC-DFTB Hessian of periodic systems. Its superiority with respect to the traditional numerical force differentiation method is demonstrated for doped graphene, graphene nanoribbons, boron-nitride nanotubes, bulk zinc-oxide, and other systems.

Comparative effects of zinc oxide and zinc oxide nanoparticle as feed additives on growth, feed choice test, tissue residues, and histopathological changes in broiler chickens.

Zinc is an essential nutritional trace mineral required for growth and health. The aim of the current work is to compare the effects of bulk zinc oxide and zinc oxide nanoparticles (ZnO-NPs) on the growth performance, feeding behavior, and zinc residues in tissues with the associated histopathological alterations in chicken. Meanwhile, the antibacterial activity against the isolated E. coli O78 strain was evaluated. Ninety Hubbard one-day-aged broiler chicks were divided into 3 groups, 30 each: birds of the 1st group fed a basal ration, those of the 2nd group fed a ration containing zinc oxide at a dose of 3000mg/kg diet, and chicks of the 3rd group are given a ration containing ZnO-NPs at a dose of 90mg/kg diet from 2 to 20days age. The experiment lasted for 35days. Feed choice test was done at the 3rd week of age on another 12 birds. Results revealed that birds fed with ZnO-NPs showed an improvement in body weight compared with the zinc oxide-administered group. There was no reluctance from birds to both diets supplemented with either zinc oxide or ZnO-NPs, with a constant preference to ZnO-NPs diet throughout the 5-min test. The highest levels of zinc were detected in the livers, kidneys, lungs, and muscles in the 1st day following cessation of drug administration. There was no significant effect on the levels of creatinine, uric acid, AST, and ALT. Mild to moderate degenerative changes as well as necrosis could be detected in the livers and hearts following both treatments. In conclusion, nano-zinc oxide could be practically used in broiler feed at a dose of 90mg/kg diet instead of bulk zinc oxide, at a dose of 3000mg/kg diet, with an improved body weight. Both supplements caused no significant effects on serum parameters and had the same antibacterial activity against E. coli O78.