Zinc Nitrate Aqueous Solution Research Articles

Temperature Dependence of Electrical Properties of ZnO Nanorods Array

Zinc oxide nanostructures (nanotubes, nanorods, nanowhiskers, etc.) are a promising material for various electronics devices for power system and green energy such as piezoelectric energy harvesters and solar cells. Electrical properties of ZnO nanorods grown on a glass substrate by the hydrothermal method in an aqueous solution of zinc nitrate were investigated in this work. The SEM micrograph shows that the grown nanorods are vertically oriented and the XRD pattern confirms its crystallinity with (002) preferred orientation. The temperature dependent resistivity of ZnO nanorods array measured from 300 to 523 K shows variation in resistance from 5·109 Ω to 3·106 W and temperature hysteresis and region with positive temperature coefficient of resistance at the heating that was not observed at cooling. The origin of this behavior is explained with the two competing processes - thermal generation of electrons and oxygen species adsorption on the ZnO surface. Oxygen adsorption leads to decrease in the number of oxygen vacancies that are electron donors, and consequently to a decrease in conductivity of ZnO nanorods. The values of activation energy of conductivity were calculated from the slope of linear regions on the Arrhenius plot which are 0.246, 1.466 and 0.248 eV for the heating curve and 0.650 and 0.315 eV for the cooling curve.

Comparison of the Characteristics of DC Discharges with a Liquid Anode and a Liquid Cathode over Aqueous Solutions of Zinc Nitrate

Comparison of the Characteristics of DC Discharges with a Liquid Anode and a Liquid Cathode over Aqueous Solutions of Zinc Nitrate

Synthesis of Zinc Oxide from Layered Zinc Hydroxide Prepared from Zinc Nitrate Aqueous Solution

Synthesis of Zinc Oxide from Layered Zinc Hydroxide Prepared from Zinc Nitrate Aqueous Solution

Features of Zinc Modification of a Zeolite Catalyst for Dimethyl Ether Conversion to Synthetic Liquid Hydrocarbons

Liquid hydrocarbons (HCs) with a low aromatic content have been synthesized from dimethyl ether (DME) in a hydrogen medium at a temperature of 340°C and a pressure of 10 MPa in the presence of catalysts based on Zn–HZSM-5 zeolites prepared by impregnation, ion exchange from an aqueous solution of zinc nitrate, and in situ synthesis. It has been shown that zinc modification of zeolite HZSM-5 leads to a decrease in the total number of acid sites with an increase in the fraction of strong Lewis acid sites in the total acidity spectrum. The introduction of Zn into zeolite HZSM-5 by the in situ method leads to an increase in the fraction of mesopores and thereby makes it possible to eliminate diffusion hindrances. These factors can provide a significant increase in the selectivity for liquid HCs and the isoalkane content in their composition and a substantial improvement in the on-stream stability of the in situ synthesized catalyst based on Zn–HZSM-5.

Voltammetric determination of ascorbic acid with zinc oxide modified glassy carbon electrode

Zinc oxide (ZnO) nanostructures electrodeposited from aqueous zinc nitrate solution at 70 °C onto glassy carbon electrode (GCE) were used as electrochemical detectors. The morphology, structure, chemical composition and conductivity of the as-deposited layers were determined using scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis and UV–Vis spectroscopy. A highly oriented crystalline ZnO deposit made of a dense array of randomly oriented hexagonal nanorods was obtained without any additives in solution. The electrocatalytic oxidation of ascorbic acid (AA) was studied using cyclic voltammetry in 0.1 M phosphate buffer solution at pH 6.8. Comparing the response for AA oxidation on the bare and modified electrodes, the peak potential was shifted to − 0.45 V on ZnO/GCE with higher current densities and transfer coefficient, due to a simultaneous increase in oxidation rate and surface area. A linear relationship was determined between the anodic peak current and the AA concentration in the range of 0.1–5 mM.

Superhydrophobic Surfaces on 5052 Aluminum Alloy Obtained from LDH Film Modified with Stearic Acid for Enhanced Corrosion Protection

This paper aimed to develop and characterize superhydrophobic surfaces with anticorrosive properties obtained by the chemical modification of the 5052 aluminum alloy with variation of acid etching time, formation of lamellar double hydroxides (LDH) film and immersion in stearic acid. The specimens were etched in HCl (2M) at 5, 10 and 30 min. The aluminum plates were treated with aqueous solution of zinc nitrate (0.1 M) in the presence of ammonia and then immersed in a stearic acid and ethanol solution (1% w/w) to reduce surface energy. Contact angles (CA) were determined. Surface morphology and composition were analyzed by scanning electron microscopy (SEM) and X-ray energy dispersion spectroscopy (EDS), respectively. Linear polarization tests were performed to analyze corrosion resistance. The optimal superhydrophobic performance was obtained with a contact angle of 154º for 30 min of acid etching. This condition also showed higher corrosion resistance, obtaining higher values of Ecorr and lower values of corrosion current density.

Application of a novel, efficient and recyclable photo redox catalyst (Zn–Al layered double hydroxide/eosin) for the synthesis of substituted pyridine derivatives under visible light irradiation

Layered double hydroxides (LDHs) are a class of anionic clays with brucite‐like layers and interlayer anions and varying in composition and morphology. LDHs show potential as supports for the immobilization of catalytically active species, to synthesize recyclable catalysts, in which catalytic sites can be preferentially orientated, highly dispersed and stabilized to afford high catalytic efficiency and recyclability in reaction media. Redox active organic dyes such as eosin Y with strong absorption in the visible region of the spectrum have been successfully used. In this work, an intercalated photo redox catalyst (Zn–Al LDH/eosin) was synthesized by co‐precipitation of an aqueous solution of zinc nitrate and aluminium nitrate simultaneously with eosin Y as anionic dye. Zn–Al LDH/eosin as a recyclable catalyst was used in the reaction of various aryl ketones and benzylamines under molecular oxygen and visible light, giving good yields of substituted pyridines at room temperature. Also, the Zn–Al LDH/eosin catalyst could be reused three times without any significant changes in the reaction yields.

Effects of precursor composition used in solution precursor plasma spray on the properties of ZnO coatings for CO2 and UV light sensing

The potential of finely-structured zinc oxide (ZnO) coatings developed via solution precursor plasma spraying (SPPS) as CO2 gas and UV light sensor was explored in this work. The coatings were deposited on stainless steel substrates using aqueous solutions of zinc nitrate and zinc acetate as precursors. The coatings' microstructures were studied in relation to the solution precursors used. Relatively porous coatings were obtained when using acetate as starting precursor compared to the coatings from the nitrate precursor. This was attributed to the different chemical routes of ZnO formation for each precursor droplet upon contact with plasma jet. Phase analysis confirmed the formation of polycrystalline ZnO having wurtzite structure from both precursors. The sprayed ZnO coatings showed good sensitivity and recovery towards UV light. Moreover, the coatings were sensitive towards carbon dioxide (CO2) analyte gas but did not show any good recovery which was attributed to the microstructure of the coatings. These results showed the feasibility of SPPS process for the fabrication of finely-structured ZnO coatings as sensors of CO2 gas and UV light.

Kinetics Modelling of the Adsorption Process of Zinc Ions by Glass Microparticles

The oligodynamic property is a lethal effect which some atoms exert over bacteria, fungi and other microorganisms. The oligodynamic property can be promoted by glass microparticles doped by zinc ionic specimens utilizing the ionic exchange processes. This study is aimed at modelling the behavior of adsorption mechanisms of the zinc ions on glass microparticles absorbent, with potential use as antimicrobial material. Aqueous solutions of zinc nitrate were used as the ionic supplying of zinc ions. The amount of zinc adsorbed on the glass was determined by spectroscopy of atomic absorption and with a mass balance analysis for each adsorption conditions. The experimental data were modeled by three Eq.s employed in adsorption kinetics studies: pseudo first order, pseudo second order and Elovich Eq.. The pseudo second order data model presented the better adjust condition. A sample of zinc glass microparticles, prepared at the finest conditions established by the kinetic model of pseudo second order, was submitted to microbiological analysis: agar diffusion test with Pseudomonas aeruginosa and Staphylococcus aureus and with Candida albicans. The glass doped with ionic zinc inhibited the growth of microorganisms in every conducted analysis.

Synthesis, characterization and evaluation of antimicrobial efficacy and brine shrimp lethality assay of Alstonia scholaris stem bark extract mediated ZnONPs

Alstonia scholaris is one of the most important medicinal plants and herein, we present the synthesis of zinc oxide nanoparticles using the bark extract of Alstonia scholaris, and evaluation of their antimicrobial efficacy. Stable ZnO nanoparticles were formed by treating 90 mL of 1 mM zinc nitrate aqueous solution with 10 mL of 10% bark extract. The formation of Alstonia scholaris bark extract mediated zinc oxide nanoparticles was confirmed by UV–visible spectroscopic analysis and recorded the localized surface plasmon resonance (LSPR) at 430 nm. Fourier transform infrared spectroscopic (FT-IR) analysis revealed that primary and secondary amine groups in combination with the proteins present in the bark extract is responsible for the reduction and stabilization of the ZnONPs. The crystalline phase of the nanocrystals was determined by XRD analysis and morphology was studied using transmission electron microscopy (TEM). The hydrodynamic diameter (26.2 nm) and a positive zeta potential (43.0 mV) were measured using the dynamic light scattering technique. The antimicrobial activity of Alstonia scholaris ZnONPs was evaluated (in-vitro) using disc diffusion method against fungi, Gram-negative and Gram-positive bacteria which were isolated from the biofilm formed in drinking water PVC pipelines. The results obtained suggested that ZnO nanoparticles exhibit a good anti-fungal activity than bactericidal effect towards all pathogens tested in in-vitro disc diffusion method (170 ppm, 100 ppm and 50 ppm). Further, the toxicity of biosynthesized ZnONPs was tested against Alstonia scholaris to evaluate the cytotoxic effect that displayed LC50 value of 95% confidence intervals.

A concentrated electrolyte for zinc hexacyanoferrate electrodes in aqueous rechargeable zinc-ion batteries

In this study, a concentrated electrolyte was applied in an aqueous rechargeable zinc-ion battery system with a zinc hexacyanoferrate (ZnHCF) electrode to improve the electrochemical performance by changing the hydration number of the zinc ions. To optimize the active material, ZnHCF was synthesized using aqueous solutions of zinc nitrate with three different concentrations. The synthesized materials exhibited some differences in structure, crystallinity, and particle size, as observed by X-ray diffraction and scanning electron microscopy. Subsequently, these well-structured materials were applied in electrochemical tests. A more than two-fold improvement in the charge/discharge capacities was observed when the concentrated electrolyte was used instead of the dilute electrolyte. Additionally, the cycling performance observed in the concentrated electrolyte was superior to that in the dilute electrolyte. This improvement in the electrochemical performance may result from a decrease in the hydration number of the zinc ions in the concentrated electrolyte.

Effect of Supplementation of Nano Zinc on Rumen Fermentation and Fiber Degradability in Goats

A study was conducted to evaluate the efficiency of nano-zinc as a feed supplement on rumen fermentation and nutrient digestibility in goats (Capra hircus). Nano-sized zinc was synthesized by using 0.45M aqueous solution of zinc nitrate and 0.9M aqueous solution of sodium hydroxide as a salt of ZnO in nano form (NZnO). The particle size thus obtained was 74 nm and later it was confirmed to be zinc by using TEM-EDAX. Twenty-four male goats were divided in four groups on the basis of BW and were supplemented with either a basal diet with concentrate and straw at 50: 50 ratio (Control) alone or supplemented with 50 ppm zinc from inorganic ZnO (IZn-50), 50 ppm zinc from NZnO (NZn-50) or 25 ppm zinc from NZnO (NZn-25). The digestibility of DM, OM, CP, EE, total carbohydrates, and nutritive value of the diets in terms of DCP, TDN (%) and ME (Mcal/kg) did not vary (P>0.05) among treatment groups. The ADF and cellulose digestibility was significantly higher (P<0.05) in all three zinc supplemented groups than control. Supplementation of graded doses of NZn did not alter the individual and total ruminal VFA profile in goats, but the soluble zinc content in the rumen liquor was higher in NZn-50 than NZn-25 and control. The rumen pH and protozoa count was higher in NZn-50 than control, IZn-50, and NZn-25. Nano Zn at 50 mg/kg DM altered the rumen pH, total protozoa count, fibre degradation and soluble zinc content in goats without affecting the individual and total VFA profile. It is concluded that nano Zn can be supplemented at half the dose of inorganic Zn without affecting rumen VFA profile, rumen soluble Zn content in goats.

Controlled Electrodeposition of Zinc Oxide on Conductive Meshes and Foams Enabling Its Use as Secondary Anode

Both compact and porous zinc oxide (ZnO) films were electrochemically deposited out of aqueous zinc nitrate solutions under pulsed galvanostatic control onto different three-dimensional (3D) substrates. Gold and carbon meshes as well as copper and nickel foams were used as substrates, all having complex geometries in micrometer dimensions with high surface area. Electrodepositions of ZnO were controlled by regulating the most relevant parameters: the applied current density, the total deposition time, and the length of current pulses and pauses to avoid gas evolution interfering with film growth at the electrodes. Optimization of these parameters for each of the substrates allowed deposition of homogeneous ZnO films of the desired total film thickness. Potential-time curves measured during deposition helped to monitor film growth. Scanning electron microscopy (SEM) micrographs showed that pinhole-free ZnO films were deposited uniformly in a 3D manner on all substrates. X-ray diffraction (XRD) measurements confirmed the formation of highly crystalline ZnO films. Such electrodeposited ZnO films on electronic conductive substrates with high surface area are promising for application in energy storage and conversion systems – especially for secondary batteries with zinc anodes which was shown by cyclic voltammetry (CV).

Characterization of mixing performance in a microreactor and its application to the synthesis of porous coordination polymer particles

Here we quantitatively evaluated the mixing performance of a tailor-made microreactor with central-collision type through the iodide/iodate chemical test reaction, and applied the microreactor to the synthesis of zeolitic imidazolate framework-8 (ZIF-8), which is a subclass of porous coordination polymers (PCPs) or metal organic frameworks (MOFs). The chemical test reaction demonstrated excellent mixing performance of the microreactor with a characteristic mixing time shorter than 1ms, which is approximately 100 times faster than those of a batch reactor and a millimeter-sized Y-shaped mixer. Taking advantage of the rapid and uniform mixing, the microreactor successfully produced ZIF-8 particles with high reproducibility by simply mixing aqueous solutions of zinc nitrate and 2-methylimidazole. The synthesis at room temperature resulted in ZIF-8 particles with chamfered cube shape, while a lower temperature of 5°C produced raspberry-type spherical particles. We confirmed that prepared ZIF-8 particles have BET surface area of ∼1500m2/g and exhibit the gate adsorption behavior caused by the structural transition of the ZIF-8 framework.

Synthesis, Crystal Structures, and Properties of Zeolite‐Like T3(H3O)2[M(CN)6]2·uH2O (T = Co, Zn; M = Ru, Os)

We report the synthesis, crystal structures, and related properties of six new zeolite‐like hexacyanometallates of formula unit T3(H3O)2[M(CN)6]2·uH2O (T = Co2+, Zn2+; M = RuII, OsII). Their crystal structures were solved and refined from their X‐ray powder diffraction patterns in combination with the IR and UV/Vis/NIR spectroscopic data. The Co and Zn ions are coordinated tetrahedrally to the N atoms of four CN groups. The deconvolution of the overlapped UV/Vis/NIR spectral bands provided conclusive evidence of the tetrahedral coordination of the Co atoms. These materials have porous frameworks, which are characterized by a 3D array of TN4tetrahedral units linked to the MC6octahedral blocks in a 3:2 ratio. From the IR spectroscopy results, we found that all of the compounds reported here contain hydronium countercations. Two different structures in the same space group (R3c) were identified for the Co‐based materials. However, only a single phase was found for the Zn‐containing compounds. Density functional theory (DFT) modeling predicts hydrogen bonds between the hydronium ions and the CN groups at the surfaces of the pores. These materials were prepared through the hydrothermal recrystallization of the solids obtained from mixing ethanol solutions of H4[M(CN)6] with aqueous solutions of cobalt(II) nitrate and zinc nitrate. Our results illustrate the potential of the hydrothermal recrystallization technique for the preparation of metal hexacyanometallates with new structures and pore topologies that are not obtainable by the traditional precipitation method.

Electrodeposition and characterization of ZnO thin films using sodium thiosulfate as an additive for photovoltaic solar cells**Project supported by the Algerian Ministry of Higher Education and Scientific Research, Algeria (No. J0101520090018).

Zinc oxide thin films have been grown by electrodeposition technique onto Cu and ITO-coated glass substrates from an aqueous zinc nitrate solution with addition of sodium thiosulfate at 90 °C. The effects of sodium thiosulfate on the electrochemical deposition of ZnO were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were obtained at −0.60 V vs. SCE and characterized by XRD, SEM, FTIR, optical, photoelectrochemical and electrical measurements. Thickness of the deposited film was measured to be 357 nm. X-ray diffraction results indicated that the synthesized ZnO has a pure hexagonal wurtzite structure with a marked preferential orientation along (002) plane. FTIR results confirmed the presence of ZnO films at peak 558 cm−1. SEM images showed uniform, compact morphology without any cracks and films composed of large flower-like ZnO agglomerates with star-shape. Optical properties of ZnO reveal a high optical transmission () and high absorption coefficient ( in visible region. The optical energy band gap was found to be 3.28 eV. Photoelectrochemical measurements indicated that the ZnO films had n-type semiconductor conduction. Electrical properties of ZnO films showed a low electrical resistivity of , carrier concentration of and mobility of 7.35 cm2 V−1 s−1.

Synthesis and characterization of ZnO nanostructures with varying morphology

Uniform fine particles of zinc oxide were prepared in three different morphologies and sizes by the controlled precipitation process from aqueous solutions of zinc nitrate in the presence of ethylene glycol. Ammonium hydroxide solution was used as the precipitant. Composition of the reactant solution, pH and temperature significantly affected the particle uniformity with respect to shape and size. Uniformity in the particles morphological feature was achieved under a narrow set of experimental conditions. pH of the reactant solutions and isoelectric point of zinc oxide were considered the master variables, controlling the particle size. One of the batch of the as-prepared zinc oxide particles was calcined at \(750{^{\circ }}\hbox {C}\), which increased its crystallinity, changed its various lattice parameters, Zn–O bond length and preferred orientation of the crystal hkl planes. Calcination had little effect on the original morphology of the zinc oxide particles.

Photodegradation of Rhodamine B by using ZnFe2O4 Nanoparticles Synthesized through Precipitation Method

ZnFe2O4 nanoparticles were synthesized through precipitation method from the mixed aqueous solution of ferric nitrate and zinc nitrate. The precipitate was calcined at the temperature of 600, 700, and 800 °C for 3 hours to obtain crystalline nature. The effects of calcination temperature on the properties of ZnFe2O4 nanoparticles were investigated. The structure, morphology, and optical properties of ZnFe2O4 nanoparticles were characterized by using X-ray diffractometer (XRD), scanning electron microscope (SEM), and UV-vis spectrophotometer, respectively. The photocatalytic activity of ZnFe2O4 nanoparticles was examined to Rhodamine B degradation in water under UV irradiation. The results show that the calcination temperature influences on ZnFe2O4 phase, crystallite size, and the energy gap of ZnFe2O4 nanoparticles. ZnFe2O4 nanoparticles calcined at 700 °C shows the best photocatalytic activity to Rhodamine B degradation due to smaller crystallite size and higher absorption.

Single crystal X-ray structure of the artists' pigment zinc yellow

The artists' pigment zinc yellow is in general described as a complex potassium zinc chromate with the empirical formula 4ZnCrO4·K2O·3H2O. Even though the pigment has been in use since the second half of the 19th century also in large-scale industrial applications, the exact structure had hitherto been unknown. In this work, zinc yellow was synthesised by precipitation from an aqueous solution of zinc nitrate and potassium chromate under both neutral and basic conditions, and the products were compared with the pigment used in industrial paints. Analyses by Raman microscopy (MRS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and powder X-ray diffraction (PXRD), showed that the synthesised products and the industrial pigment were identical. Single-crystal X-ray crystallography determined the structure of zinc yellow as KZn2(CrO4)2(H2O)(OH) or as KZn2(CrO4)2(H3O2) emphasizing the μ-H3O2− moiety. Notably, the zinc yellow is isostructural to the recently structurally characterized cadmium analog and both belong to the natrochalcite structure type.

Photoluminescence study of Eu+3 doped ZnO nanocolumns prepared by electrodeposition method

Europium doped ZnO (ZnO:Eu) nanocolumns were grown on indium tin oxide substrates (ITO) by electrodeposition method in zinc nitrate aqueous solution with different concentration of Eu. According to XRD results electrodeposited ZnO:Eu films exhibit thigh crystalline quality with a preferential orientation parallel to c-axis. Moreover, the (002) peak position shifts toward to lower angles confirming the incorporation of Eu+3 ions into the ZnO lattice. The crystallite size of a pure ZnO decreases when increasing the Eu doping. SEM images reveal a well dense nanocolumns arrays perpendicular to the surface. Furthermore, doping with Eu+3 ions leads to a change in the top of nanocolumns from hexagonal to conic-hexagonal shape. The average diameters of nanocolumns are found to be around 200nm and 180nm for undoped ZnO and Eu doped ZnO, respectively. Photoluminescence (PL) emission from ZnO:Eu thin films reveals the typical peaks related to excitons and intrinsic defects in ZnO and four narrow peaks in the red region attributed to 4f-shell transition in Eu+3 ions. As Eu doping increased, PL peaks related to Eu+3 emission showed an increase in intensity and a shift in its wavelength position. A schematic drawing of the excitation mechanism and related emission process is proposed.