Zinc In Solution Research Articles

Usage of Non-chemical Methods to Counter the Damages Caused by Tomato Mosaic Virus

Background: Tomato mosaic virus (ToMV) is the most common and important pathogen of tomato crop. The infected plants show mosaic, mottle, wrinkling, reduced leaf size and uneven ripening of fruits. ToMV is transmitted mechanically, by cultural operations, farm implements and also through seed. Methods: The present study was planned to evaluate environment friendly strategies for the management of ToMV disease. Different non-chemical means viz., Elephant Ear plant extract, Eucalyptus extract, Zinc and Boron solution, NPK solution, Milk and Urea were used on four tomato varieties (Tanja, Chico, Manik and Sahil). All the treatments were used at three different concentrations (1%, 2% and 3%) and replicated three times. Result: The maximum disease reduction was recorded in plants treated with NPK solution (16.35%) and minimum in plants treated with Elephant Ear plant extract (29.65%). The maximum mean disease severity was recorded at 1 percent concentration of all the treatments (32.46%) which was statistically significant from that of 2 and 3% (24.74% and 19.23%), respectively. Among the varieties, minimum disease severity was recorded in Manik (24.64%) variety and maximum in Chico (31.27%) variety. All the treatments contributed towards reduction in disease severity of which NPK solution being most efficient.

COMPARATIVE OF NATURAL ZEOLITE – CLINOPTILOLITE ELIMINATION OF METAL IONS/ESPECIALLY Cu (II) WITH D-PENICILLAMINE FROM BIOLOGICAL ENVIRONMENTS

Clinoptilolite is used as an adsorbent to remove heavy metal cations due to its function as a molecular sieve. This molecular sieve characteristic has made it possible to study the efficiency of clinoptilolite and D-Penicillamine in a comparative way in terms of the adsorption of heavy metals (especially copper) from a biological medium. For this purpose, clinoptilolite was subjected to grinding to produce a homogenized micronized powder in two sizes with d90=75 and 150 μm. Then, initial adsorption tests in an aqueous medium were performed on 10 ppm solutions of iron, zinc, copper, cadmium and nickel cations in single cation solutions, as well as a mixture of cations. In the next step, tests were performed to evaluate the adsorption of Cu2+ on clinoptilolite under different conditions. Experiments have been performed to investigate the effect of pH, temperature (T), adsorbent dosage, time and cation concentration in a simulated biological medium. According to the results, clinoptilolite has a high ability to remove metal cations from aqueous solutions. The 99.71% removal of copper cations by clinoptilolite indicates the high ability of this mineral to remove copper from any environment. In a simulated biological medium at pH=7 and 5, the copper adsorption rate was 98.18% and 97.45% respectively, which indicates the high ability of zeolite to absorb copper cations under biological conditions. An examination of the mass balance calculations has also shown the ability to replace clinoptilolite with penicillamine; 15 mg of clinoptilolite removes 214 mg of Cu from aqueous solutions, which is equivalent to the formation of copper-penicillamine chelate.

Chemical composition of nanomodified cement stone

Improving the properties of cement building materials is possible with the use of modifiers, including nanoscale ones. Such nanomodifiers include hydrosilicates of zinc and copper. The increase in the performance characteristics of nanomodified cement composites is due to changes in the chemical composition of the resulting cement stone, in particular, an increase in the content of hydrosilicate structures. The chemical composition of the cement stone was studied by FTIR-spectroscopy. Colloidal solutions of zinc and copper hydrosilicates with known characteristics were used for the nanomodification of cement stone. It is shown that when using copper hydrosilicates synthesized at high concentrations of iron hydroxide, the concentration of amorphous silica does not significantly affect the composition of cement stone. However, with a decrease in the concentration of iron hydroxide, with an increase in the concentration of amorphous silica, the content of hydrosilicate structures increases. The use of nanoscale zinc hydrosilicates is more efficient than copper hydrosilicates. Their use makes it possible to increase the content of structures containing silicon-oxygen tetrahedra, submicrocrystalline calcium hydrosilicates of a tobermorite-like structure in cement stone, and the formation of ettringite is also noted. Thus, it was found that the use of zinc hydrosilicates as nanomodifiers for cement stone allows increasing the content of hydrosilicate structures in hydration products.

Effect of Reaction Product of Epichlorohydrin and Imidazole on the Electrodeposition Behavior of Zn-Ni Alloy from Alkaline Zincate Solution

Effect of Reaction Product of Epichlorohydrin and Imidazole on the Electrodeposition Behavior of Zn-Ni Alloy from Alkaline Zincate Solution

GATA factor-regulated solute carrier ensemble reveals a nucleoside transporter-dependent differentiation mechanism.

Developmental-regulatory networks often include large gene families encoding mechanistically-related proteins like G-protein-coupled receptors, zinc finger transcription factors and solute carrier (SLC) transporters. In principle, a common mechanism may confer expression of multiple members integral to a developmental process, or diverse mechanisms may be deployed. Using genetic complementation and enhancer-mutant systems, we analyzed the 456 member SLC family that establishes the small molecule constitution of cells. This analysis identified SLC gene cohorts regulated by GATA1 and/or GATA2 during erythroid differentiation. As >50 SLC genes shared GATA factor regulation, a common mechanism established multiple members of this family. These genes included Slc29a1 encoding an equilibrative nucleoside transporter (Slc29a1/ENT1) that utilizes adenosine as a preferred substrate. Slc29a1 promoted erythroblast survival and differentiation ex vivo. Targeted ablation of murine Slc29a1 in erythroblasts attenuated erythropoiesis and erythrocyte regeneration in response to acute anemia. Our results reveal a GATA factor-regulated SLC ensemble, with a nucleoside transporter component that promotes erythropoiesis and prevents anemia, and establish a mechanistic link between GATA factor and adenosine mechanisms. We propose that integration of the GATA factor-adenosine circuit with other components of the GATA factor-regulated SLC ensemble establishes the small molecule repertoire required for progenitor cells to efficiently generate erythrocytes.

Characterizing the Soldering Alloy Type Zn–Al–Cu and Study of Ultrasonic Soldering of Al7075/Cu Combination

The aim of the research was to characterize the soldering alloy type Zn–Al–Cu and study the fluxless ultrasonic soldering of the combination of aluminum alloy type Al7075 with copper substrate. The Zn–Al–Cu solder is of the close-to-eutectic type with two phase transformations: the eutectic transformation at 378 °C and the eutectoid transformation at 285 °C. The solder microstructure is formed of a matrix composed of the solid solutions of aluminum (Al) and zinc (Zn) in which the copper phases CuZn4 and CuAl2 are precipitated. The shear strength of the soldering alloy type Zn5Al with copper addition reaches values from 167 to 187 MPa and it depends on the copper content in the solder. The bond with aluminum alloy type Al7075 is formed due to the solubility of Al in zinc solder at the formation of solid solution Al. Contrary to this observation, the bond with the copper substrate is in this case formed due to the interaction of zinc and aluminum with the copper substrate. Two new intermetallic phases, namely Al(Cu,Zn)2 and Cu3.2Zn0.7Al4.2, were formed. The average shear strength of Al7075/Zn5Al3Cu/Cu joints attained was 134.5 MPa. For comparison, the Cu/Zn5Al3Cu/Cu joint attained an average shear strength of 136.5 MPa.

Influences of Zinc Content and Solution Heat Treatment on Microstructure and Corrosion Behavior of Mg-Zn Binary Alloys

The influences of Zn content and heat treatment on microstructure and corrosion behavior of Mg-xZn (x = 1 wt%, 3 wt%, 5 wt%, and 7 wt%) alloys were studied. (α-Mg+MgZn) eutectic cells and Zn-segregated regions were formed in the as-cast alloys. The Zn-rich phases acted as microcathodes in galvanic corrosion. Volume fraction of the Zn-rich phases increased with Zn content of the as-cast alloys, leading to a decrease in corrosion resistance. The corrosion rate of the as-cast alloys increased four times with an increase of the volume fraction of eutectic cell from 0.07 vol% of Mg-1Zn alloy to 2.18 vol% of Mg-5Zn alloy. The corrosion rate of Mg-7Zn alloy with 2.87 vol% eutectic cells was two times higher than that of Mg-5Zn alloy. The Zn-rich phases dissolved by the T4 treatment and only the T4-treated Mg-7Zn alloy obviously showed eutectic cells of 1.73 vol%. The polarization resistance (Rp) of the T4-treated Mg-1, 3, and 5Zn alloys was 2 to 10 times higher than that of the as-cast alloys. The T4-treated Mg-7Zn showed similar Rp to the as-cast Mg-5Zn alloy. Consequently, the volume fraction of Zn-rich phases dominated the corrosion resistance of Mg-xZn alloys.

Peculiarities of doping of ZnO:Mn nanocrystals during their synthesis by the aerosol pyrolysis method

Samples of ZnO:Mn nanocrystals with Mn concentrations of 2 and 4 at.% were synthesized by ultrasonic aerosol pyrolysis. The synthesis was carried out at 550°C using aqueous solutions of zinc and manganese nitrates. The samples obtained were subjected to heat treatment at 550°C and 850°C in air for 1 hour. The study of the samples by XRD and EPR methods shows that during the synthesis the process of doping ZnO nanocrystals with manganese occurs only partially, on the surface, in the near-surface layer. Residues of the Mn impurity are located on the surface of nanocrystals and appear during annealing at 550°С in the form of manganese oxides (Mn2O3). During heat treatment at 850°C, decomposition of Mn2O3 and bulk doping of ZnO:Mn nanocrystals occur.

Does galvanic cathodic protection by aluminum anodes impact marine organisms?

BackgroundCathodic protection by sacrificial anodes composed of aluminum-zinc-indium alloys is often applied to protect offshore support structures of wind turbines from corrosion. Given the considerable growth of renewable energies and thus offshore wind farms in Germany over the last decade, increasing levels of aluminum, indium and zinc are released to the marine environment. Although these metals are ecotoxicologically well-studied, data regarding their impact on marine organisms, especially sediment-dwelling species, as well as possible ecotoxicological effects of galvanic anodes are scarce. To investigate possible ecotoxicological effects to the marine environment, the diatom Phaedactylum tricornutum, the bacterium Aliivibrio fischeri and the amphipod Corophium volutator were exposed to dissolved galvanic anodes and solutions of aluminum and zinc, respectively, in standardized laboratory tests using natural seawater. In addition to acute toxicological effects, the uptake of these elements by C. volutator was investigated.ResultsThe investigated anode material caused no acute toxicity to the tested bacteria and only weak but significant effects on algal growth. In case of the amphipods, the single elements Al and Zn showed significant effects only at the highest tested concentrations. Moreover, an accumulation of Al and In was observed in the crustacea species.ConclusionsOverall, the findings of this study indicated no direct environmental impact on the tested marine organisms by the use of galvanic anodes for cathodic protection. However, the accumulation of metals in, e.g., crustaceans might enhance their trophic transfer within the marine food web.

Linear Metal-Organic Frameworks Based on Bis(1-Benzotriazolyl)methane and Zinc and Copper Nitrates

Complexes {[(Zn(Bbtm)(H2O)4](NO3)2}n (I) and [Cu(Вbtm)(NO3)2]n (II) are formed due to the reactions of solutions of zinc and copper(II) nitrates with the bis(1,1'-1,2,3-benzotriazolyl)methane ligand (Bbtm). Their crystal structures are determined by X-ray diffraction analysis (CIF files ССDС nos. 1963126 (I) and 1963127 (II)). Complex I is a linear metal-organic framework (1D-MOF) in which the octahedral coordination of the central atom is provided by four water molecules and two nitrogen atoms of two Bbtm molecules in the trans position. In the structure of complex II, the coordination sphere of copper contains two nitrogen atoms of the Вbtm ligands and four oxygen atoms of two nitrate anions, one of which is bridging like the Вbtm ligand. This makes it possible to describe the structure of complex II as 3D-MOF. The luminescence spectra are recorded for earlier undescribed compound I. The emission maximum is observed at 363 nm. Compound I is also tested as a catalyst for the cycloaddition of СО2 to epoxides. The synthesized MOF efficiently catalyzes the cycloaddition reactions for both monosubstituted and disubstituted epoxides.

54 Effects of an injectable zinc solution at weaning as an alternative castration method during the backgrounding period in beef bulls

Abstract Castration is a routine management practice performed on an estimated 15 million bull calves each year in the United States. Although castration is a common practice worldwide, the process causes pain and stress that temporarily reduces performance. The objective of our study was to investigate the effects of a novel injectable zinc solution as an alternative castration method on the growth performance, testicular width, and serum testosterone concentrations of weaned beef bulls. Calves (n = 74) were processed at birth and were randomly assigned to 1 of 2 castration methods: 1) negative control, in which calves were surgically castrated at birth, or 2) chemically castrated, in which calves remained intact males until weaning and were chemically castrated with a 1 mL intratesticular injection of zinc solution in each testicle. Data were analyzed using the MIXED procedures of SAS and significance was declared at P < 0.05. Chemically castrated calves were heavier (P < 0.01) throughout the 168-d backgrounding phase compared to steers (285 and 266 kg respectively); however, the overall change in BW (P = 0.73) and ADG (P = 0.81) was similar between castration techniques. Testicular width measurements were greatest on d 28 and returned to baseline weaning measurements by d 56. Testicular width continued to decrease on d 77 and remained constant for the remainder of the backgrounding period (time P < 0.01). Although testicular width decreased, chemically castrating did not affect (time P = 0.17) testosterone concentrations; however, concentrations were numerically lowest on d 28 and 56. Chemically castrating cattle at weaning resulted in greater overall body weights and reduced testicular width during the backgrounding period; however, it did not eliminate testosterone production as compared to surgically castrating at birth. This solution was not effective in bulls at weaning.

53 Effects of an injectable zinc solution at weaning as an alternative castration method during the backgrounding period in beef bulls

Abstract Castration is a routine management practice performed on an estimated 15 million bull calves each year in the United States. Although castration is a common practice worldwide, the process causes pain and stress that temporarily reduces performance. The objective of our study was to investigate the effects of a novel injectable zinc solution as an alternative castration method on the growth performance, testicular width, and serum testosterone concentrations of weaned beef bulls. Calves (n = 74) were processed at birth and were randomly assigned to 1 of 2 castration methods: 1) negative control, in which calves were surgically castrated at birth, or 2) chemically castrated, in which calves remained intact males until weaning and were chemically castrated with a 1 mL intratesticular injection of zinc solution in each testicle. Data were analyzed using the MIXED procedures of SAS and significance was declared at P < 0.05. Chemically castrated calves were heavier (P < 0.01) throughout the 168-d backgrounding phase compared to steers (285 and 266 kg respectively); however, the overall change in BW (P = 0.73) and ADG (P = 0.81) was similar between castration techniques. Testicular width measurements were greatest on d 28 and returned to baseline weaning measurements by d 56. Testicular width continued to decrease on d 77 and remained constant for the remainder of the backgrounding period (time P < 0.01). Although testicular width decreased, chemically castrating did not affect (time P = 0.17) testosterone concentrations; however, concentrations were numerically lowest on d 28 and 56. Chemically castrating cattle at weaning resulted in greater overall body weights and reduced testicular width during the backgrounding period; however, it did not eliminate testosterone production as compared to surgically castrating at birth. This solution was not effective in bulls at weaning.

Decomposition of a Potassium-Based Supersaturated Zincate Solution in Electrolytes with Reduced Zinc Solubility

The decomposition rate of supersaturated zincate electrolytes based on 6 mol·dm-3 KOH was measured and the effect of additives used for reducing zincate solubility (KF, K2CO3, K3PO4) was evaluated. The electrolytes were studied after being aged for 5 years at room temperature. Powder morphology was obtained as a result of recrystallization processes were evaluated. Results indicate that the presence of 1 mol·dm-3 PO4 3- ions reduced the speed of decomposition to less than half. A study of ZnO recrystallization revealed the changes in particle sizes for all additives. Despite the long time of recrystallization processes, ZnO particles grew to different sizes depending on the type of low solubility electrolyte (LSE) used. While the presence of PO4 3- and F- ions promote the particle growth in all directions and thus influence both particle lengths and widths. The presence of carbonate ions CO3 2- reduce the particle sizes and thus could contribute to the growth of a larger active area of electrodes after long-term aging.

(Invited) Zinc-Deposited Aluminum Electrode Prepared Using Spontaneous Deposition Method for Use in Aqueous Hybrid Capacitors

Aqueous electrolytes have advantages compared to nonaqueous electrolytes, such as high ionic conductivity, nonflammability, low environmental load, low cost, and so on. However, the maximum operating voltages of electric double-layer capacitors (EDLCs) with aqueous electrolytes are much lower than those with nonaqueous electrolytes, which can operate at voltages over 2.5 V, because the former are limited to 1.23 V, the theoretical decomposition voltage of water, leading to low energy and power densities. So, a key to improve energy and power densities is to increase the maximum operating voltage. Hybrid capacitors (HCs), which consists of activated carbon (AC) and redox electrodes, can greatly improve the energy and power densities of EDLCs because of widened potential windows. As for aqueous HCs, metal hydroxides/oxides as a redox positive electrode have realized the maximum operating voltages of 1.4–2.0 V because they have higher potential limits and higher oxygen overpotentials than AC,1-3 leading to higher energy and power densities. In the same manner, we reported that an HC with a Zn negative electrode whose hydrogen overpotential was larger than AC also increased the maximum operating voltage due to the extension of the negative potential limits, leading to low energy and power densities.4 A copper sheet was used as a substrate for zinc electrodeposition in the previous study.4 Aluminum is a light metal and cheap. Since the standard potential of Al is more negative than that of Zn, Zn can be spontaneously deposited on an Al sheet only by immersing it in a zincate solution. In this study, we prepared Zn-deposited Al sheet negative electrodes and evaluated their electrochemical properties and capacitor performance of a HC with the negative electrode.A polished Al sheet was immersed in a zincate solution to deposit Zn metal spontaneously. After the deposition, the mirror image of the Al sheet was cloudy due to zinc deposits. EDX and XPS analyses showed that Zn deposits covered almost the whole Al surface, indicating that spontaneous deposition of Zn occurred as follows.2Al + 3Zn(OH)4 2- → 3Zn + 4OH- + 2Al(OH)4 - Cyclic voltammograms of a Zn/Al electrode were recorded in 7 M KOH aqueous solution containing 0.6 M ZnO. A reduction peak due to Zn deposition and an oxidation peak due to Zn dissolution were observed in cyclic voltammograms, which was similar to a cyclic voltammogram of a Cu electrode in the same electrolyte.An aqueous HC cell with a Zn/Al negative electrode and AC positive electrode was assembled, and its capacitor performance will be reported. References V. Khomenko, E. Raymundo-Piñero, F. Béguin, J. Power Sources, 153, 183 (2006).T. Cottineau, M. Toupin, T. Brousse, D. Bélanger, Appl. Phys. A: Mater. Sci. Process., 82, 599 (2006).H. Inoue, Y. Namba, E. Higuchi, J. Power Sources, 195, 6239 (2010).H. Inoue, T. Morimoto, S. Nohara, Electrochem. Solid-State Lett., 10, A261 (2007).

Pulsed Current Vs. Organic Additives on Electrodeposition from Zincate Bath

Among the various zinc electroplating baths, alkaline zincate solution has gained a wider range of applications thanks to its simple bath composition, good dispersion and efficient coverage ability. Nevertheless, alkaline zincate solution cannot be used as such and it is necessary to introduce additives to control the process performances [1]. Otherwise, efficiency is extremely low, and the properties of the coatings are disappointing. Additives can modify the crystal growth and therefore the structural and mechanical properties, the corrosion resistance, and the appearance of coatings [2]. In the absence of additives, the main problem is low efficiency, resulting from the competition between dihydrogen production and the reduction of the metallic species present in the bath.Therefore, pulsed currents constitute an attractive way to eliminate the need for organic additives by significantly improving the Faradic yield. In this study, the influence of various pulsed current sequences versus the addition of organic additives is observed in the characteristics of the coatings as well as in the process execution. A key point in the determination of the pulse sequence is the study of the transient curves with a zincate bath. This allows for the identification of the most influential parameters on dihydrogen production, with direct consequences on the process mechanisms.By knowing the τD i.e. diffusion time preceding hydrogen reduction, it is possible to design pulse sequences with limited gas production. This is confirmed by mass spectrometry measurements which quantify the total dihydrogen production for each pulse sequence. Fig 1.The coating’s characterization consists in SEM analysis topographic pictures and preferential orientations and grain sizes determined through XRD. Results confirm the interest of pulsed currents versus organic additives for zincate baths.[1] J. L. Ortiz-Aparicio, Y. Meas, G. Trejo, R. Ortega, T. W. Chapman, et E. Chainet, « Effects of organic additives on zinc electrodeposition from alkaline electrolytes », J Appl Electrochem, vol. 43, no 3, p. 289-300, mars 2013, doi: 10.1007/s10800-012-0518-x.[2] L. Yuan, Z. Ding, S. Liu, W. Shu, et Y. He, « Effects of additives on zinc electrodeposition from alkaline zincate solution », Transactions of Nonferrous Metals Society of China, vol. 27, no 7, p. 1656-1664, juill. 2017, doi: 10.1016/S1003-6326(17)60188-2. Figure 1

Recovery of Cobalt from the Residues of an Industrial Zinc Refinery

The electrolytic production of metallic zinc from processing zinc sulfide concentrates generates a residue containing cadmium, copper, and cobalt that need to be removed from the electrolytic zinc solution because they are harmful to the zinc electro-winning process. This residue is commonly sent to other parties that partly recover the contained elements. These elements can generate revenues if recovered at the zinc plant site. A series of laboratory tests were conducted to evaluate a method to process a zinc plant residue with the objective of recovering cobalt into a salable product. The proposed process comprises washing, selective leaching, purifying and precipitation of cobalt following its oxidation. The process allows the production of a cobalt rich hydroxide precipitate assaying 45 ± 4% Co, 0.8 ± 0.2% Zn, 4.4 ± 0.7% Cu, and 0.120 ± 0.004% Cd at a 61 ± 14% Co recovery. Replicating the whole process with different feed samples allowed the identification of the critical steps in the production of the cobalt product; one of these critical steps being the control of the oxidation conditions for the selective precipitation step.

Investigation of Cu/Zn/Ag/Mo-based impregnated activated carbon for the removal of toxic gases, synthesized in aqueous media

Impregnated activated carbons (IACs) have been prepared successfully from aqueous solution of copper, zinc, silver and molybdenum for the removal of toxic gases from air. First, the activated carbon was impregnated by imbibing limit method with single metal, then a combination of 2 to 4 metals was used. The aim of this study was to access the adsorption capability of raw activated carbons (RAC) and IACs for SO2 and NO2 gases. Different techniques such as XRD, TEM, SEM, EDX mapping, AAS and BET surface area analyzer were used for characterization of materials. Results indicate that IACs provided satisfactory protection against challenge gases. Using the FTIR based gas analyzer, a significant increase in breakthrough time of all IACs was observed as compared to RAC. The maximum breakthrough time was achieved with four metals (Cu, Zn, Ag and Mo) impregnated on activated carbon i.e. 120.5 min for SO2 and 139.0 min for NO2, which were 13 and 25 times high respectively, in comparison with RAC. Adsorption capacity was found to be 320 mg SO2/g-C and 380 mg NO2/g-C. In comparison with RAC, ASZM2 carbon showed enhanced adsorption capability up to 30 times for SO2 and 40 times for NO2.

Flexible thermoelectric module based on zinc oxide thin film grown via SILAR

In this work, we used the low temperature solution growth Successive Ionic Layer Adsorption and Reaction (SILAR) for a deposition of the nanostructured undoped and indium doped (ZnO and ZnO:In) thin films on flexible polyimide (PI) substrates for their use as cheap non-toxic thermoelectric materials in the flexible thermoelectric modules of planar type to power up portable and wearable electronics and miniature devices. The use of a zincate solution in the SILAR method allows to obtain ZnO:In film, which after post-growth annealing at 300 °C has low resistivity ρ ≈ 0.02 Ω m, and high Seebeck coefficient −147 μV/K and thermoelectric power factor ~1 μW K−2 m−1 at near-room temperatures. As evidence of the operability of the manufactured films as the basis of the TE device, we have designed and tested experimental lightweight thin-film thermoelectric module. This TE module is able to produce specific output power 0.8 μW/m2 at ΔT = 50 K.

Structural, Optical and Photocatalytic Characterization of ZnxCd1−xS Solid Solutions Synthetized Using a Simple Ultrasonic Radiation Method

A simple ultrasonic radiation method was employed for the preparation of zinc and cadmium sulfide solid solution (ZnxCd1−xS; x = 0–0.25 wt.%) with the aim to investigate its efficiency for H2 production via a visible light-driven water-splitting reaction. The catalyst characterization by X-ray diffraction confirmed the formation of solid solution (ZnxCd1−xS) between CdS and ZnS phases. All catalysts exhibited hierarchical morphology (from SEM and TEM) formed by aggregated nanoparticles of ZnxCd1−xS solid solution with crystals showing mainly (111) planes of cubic CdS phase. The crystal size linearly decreased with an increase in Zn incorporation in the crystal lattice (from 4.37 nm to 3.72 nm). The ZnxCd1−xS photocatalysts showed a gradual increase in the H2 evolution, with an increase in the Zn concentration up to 0.2 wt.% making the most effective Zn0.2Cd0.8S catalyst toward H2 production. From the catalyst activity–structure correlation, it has been concluded that the twin-like CdS structure, the (111) plane and specific morphology are the main factors influencing the catalyst effectivity toward H2 production. All those factors compensated for the negative effect of an increase in band gap energy (Ebg) after ZnS incorporation into solid solution (from 2.21 eV to 2.34 eV). The effect of the catalyst morphology is discussed by comparing H2 evolution over unsupported and supported Zn0.2Cd0.8S solid solutions.

Structure and properties of rapidly solidifing foils Sn – 14 at.% In – 6.5 at.% Zn

The results of studies of the effect of ultra-high cooling rates of the melt equal to 10 5 K/s on the phase composition, microstructure, grain structure and mechanical properties of the Sn – 14 at.% In – 6.5 at.% Zn alloy are presented. To prepare the samples, the rapid quenching from the melt technique was used. A drop of melt was injected onto the inner surface of a rapidly rotating copper cylinder and solidifing in the form of a foil with a thickness of 30–90 μm. Investigations of the phase composition, carried out by the method of Х-ray diffraction analysis, made it possible to establish that the foil consists of a solid solution of zinc in the γ -phase (Sn4In) and zinc. Observations of the microstructure of the foil using scanning electron microscopy showed that the decomposition of a supersaturated solid solution proceeds at room temperature with the release of dispersed zinc particles. The character of the grain structure and texture of the foil is studied by the electron backscatter diffraction technique. A mechanism of the formation of elongated grains is proposed, which consists in the fact that at a high solidification rate, comparable to the rate of movement of the melt over the surface of the mold, grain growth can occur not only in the direction opposite to the direction of heat removal, but also in the direction of movement of the spreading. The formation of the preferred growth of grains, in which the most closely-packed plane (0001) is parallel to the foil surface, provides the maximum rate of decrease in the enthalpy of the alloy during crystallization. The features of the influence of the microstructure and grain structure on the mechanical properties of the foil are revealed. The microhardness of the rapidly solidifing Sn – 14 at.% In – 6.5 at.% Zn alloy is 105 MPa. The stress–strain curve of the Sn – 14 at.% In – 6.5 at.% Zn foil, obtained at room temperature, has a shape specific for the stress–strain curve of metals at high temperatures, which is due to the low melting point of the γ-phase.