Metal Salt Solutions Research Articles

Evolution of novel nanostructured MoCoFe-based hydroxides composites toward high-performance electrochemical applications: Overall water splitting and supercapacitor

Metal hydroxides are versatile and appealing electrode materials owing to their merits such as easy room-temperature synthesis, nanostructures formation, higher conductivity, crystallite or non-crystallite formation, porous structures, etc. Herein, nanostructured ternary transition metal (M = Mo, Co, Fe) hydroxides (TTMHs) are successfully grown on nickel foams via template-free single-step electrodeposition for overall water splitting and supercapacitor applications. Interestingly, numerous element ratios of Mo5+, Co2+, and Fe3+ in the electrodeposition precursor solutions manifested novel nanostructures viz nanosheets, nanoflakes, nanoparticles, and nanograss-like structures were evolved for different precursor solutions. For water splitting, a negative electrode prepared using aqueous Mo:Co:Fe (4.0:4.0:2.0 M ratio) metal salt solution that exhibited excellent hydrogen evolution activity with 98 mV overpotential, whereas a positive electrode (Mo:Co:Fe = 3.0:3.5:3.5) shows efficient oxygen evolution with 227 mV overpotential, and a full cell assembled from these active electrodes exhibited lower 1.56 V cell voltage at 10 mAcm−2. For the supercapacitor, a working electrode with composition Mo:Co:Fe = 6.0:2.0:2.0 showed 3354.7 mFcm−2 high areal capacitance at 1.0 mAcm−2 with excellent retention (91% after 3000 cycles). An asymmetric supercapacitor (ASC) device was fabricated that exhibited enormous energy and power densities of 1.27 × 10−3 Whcm−3 and 3.75 Wcm−3, respectively. The high-performances of both devices (water splitting full cell and supercapacitor) are due to the unique composition of hybrid electrodes (with nanostructured morphology) and synergistic effects. The present investigation demonstrates a simple strategy for preparing potential TTMHs composite electrodes with the evolution of different morphologies for multiple electrochemical applications.

One-Step Synthesis of Functional Sulfonated Polynaphthoylenebenzimidazoles for Biosensing Applications

Polynaphthoylenebenzimidazoles containing functional sulfo groups were synthesized by a one-step method in a sulfuric acid medium with oleum. A polymer-analogous transformation of these polymers with aqueous solutions of metal salts (K, Ca, and Cr) was carried out. Their chemical structure was characterized by FTIR, NMR, and elemental analysis. Polymer salt coatings were deposited on QCM sensor surfaces by electron beam-induced vacuum deposition. The morphology of the coatings was characterized by AFM. It was shown that the coatings formed from a series of polymer salts have different adsorption activity in acetaminophen–water solution compared to distilled water. The QCM results indicate that sensor signal correlates with polymer coating thickness, morphology, and its chemical composition.

Методика оптического детектирования метана волоконно-оптическом сенсором при применении фотокаталитического нанокомпозита ZnO-SnO-=SUB=-2-=/SUB=--Fe-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

The possibility of detection of methane using fiber-optical sensor with ZnO-SnO2-Fe2O3 photocatalyst was demonstrated. Photocatalytic composite sensor element was prepared by non-isothermal polymer-salt method from solutions of inorganic metal salts and polyvinylpyrrolidone. Optical detection is carrying out by Bragg diffraction grating of fiber-optical sensor at the temperature variations during photocatalytic methane oxidation.

Optimization of Green Synthesized Black Tea Nanoparticles using Central Composite Design

Objectives: Traditional method of optimization is lengthy and time consuming while response surface methodology evaluates the effects of multiple factors and their interactions on one or more response variables with fewer experiments. The aim of present study is optimization of green synthesized black tea nanoparticles using central composite design. Materials and Methods: 5, 15, and 25% black tea concentrations were reacted with 5, 10, and 15 mM Silver nitrate (AgNO3). An optimization study was carried out to optimize the levels of the independent factors like concentration of extract, solution of Silver nitrate, stirring speed, and stirring time. 30 numbers of experiments were performed and evaluated for responses like particle size and % yield. Characterization of silver nanoparticle was done by UV-visible spectroscopy, zeta sizer, XRD, FTIR, FESEM, etc. Results: Nanoparticles formation was revealed by color transformation from light yellow to brown. Prepared particles were monodisperse with Z-Average: 137.8 nm, polydispersity index 0.278, and Zeta potentials 22.7 mV. Electrophoretic Mobility Mean was 0.000176 cm 22/Vs, indicating the stability of silver nanoparticle suspension. Conclusion: Optimized parameters offered by Central Composite Design were 10mM AgNO3, 10% extract of black 150 min, and 700 rpm. 3D plots revealed that the metal salt concentrations and stirring rate showed a direct relationship whereas extract concentration and stirring time showed indirect relationship with particle size. % yield was highest with mid level of solution of metal salt (A) and concentration of extract (B) Stirring time (C) and stirring speed had no impact on % yield.

Continuous Flow Synthesis of Cd1-x Znx S and CdS/ZnS Core/Shell Semiconductor Nanoparticles by MicroJet Reactor Technology.

From aqueous precursor solutions of metal salts and sodium sulfide using MicroJet Reactor (MJR) technology Cd1-x Znx S and CdS/ZnS core/shell semiconductor nanoparticles were synthesized. The MJR approach represents an automated, continuous, flexible and scalable route for nanoparticle synthesis, providing a tight control over process parameters and thus simple size, shape and composition control. Since particle sizes below the excitonic Bohr radius were obtained by MJR, the nanoparticulate materials exhibit quantum confinement effects. By varying the precursor ratio the band gap of Cd1-x Znx S Quantum Dots (QDs) could be targeted from 3.1 to 3.6 eV. CdS/ZnS core/shell QDs were prepared by enclosing CdS particles from MJR with ZnS produced by thermal decomposition of a Zn-MPA complex. Adjustment of the shell thickness increased the photoluminescence intensity by 43 %. Synthesis of ternary sulfides in the form of core/shell particles broadens the spectrum of materials accessible by MJR and demonstrates the extraordinary flexibility of the technology.

Biosynthesis of Silver Nanoparticles, Bioactivity Profiling and Assessment of Photocatalytic Dye Degradation Activity in Punica granatum Juice

Abstract: The textile businesses, particularly dyeing industry is the major polluter in the globe, since the dye manufacturing necessitates a huge quantity of water. Plant mediated nanomaterials has the potential to dramatically accelerate the green revolution in the nanomaterial sectors where environmental contamination is a major problem. In the present study, Punica granatum fruit juice was used as plant source to carry out the green synthesis of AgNPs, reported for the first time. The Punica granatum is rich in polyphenols and flavonoids, responsible in the reduction of Ag+ ions to form AgNPs. The synthesized Punica granatum AgNPs were investigated using UV-vis spectrophotometry, where they had exhibited a visible color change and the maximum absorption peak at 421nm, confirming the formation Punica granatum AgNPs. The SEM analysis had revealed the particles morphology and confirmed the rectangular, spherical and rod structure of the particles. The FTIR analysis had shown the presence of different functional group responsible in the reduction and formation of AgNPs. Further, the dynamic light scattering has depicted the average size to be 228.3nm of the formed AgNPs and the size distribution of the particles in the colloidal solution. The photocatalytic degradation MB dye was carried out using the biosynthesized AgNPs and NaBH4, resulting in 99.4% degradation activity, with an increased concentration of the colloidal Punica granatum AgNPs. The quantitative detection of heavy metal salt solution was performed, with the use of Punica granatum AgNPs as a biosensor, showed its sensitivity towards mercury. The antibacterial activity performed against the following bacteria Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Proteus sp., which had resulted in the formation of a clear zone of inhibition. Punica granatum AgNPs had also showed maximum of 80.94% of DPPH scavenging activity.

Bioaccumulation of Trace Elements from Aqueous Solutions by Selected Terrestrial Moss Species.

The interrelationship between metal concentrations in mosses and their surroundings prompts research toward examining their accumulation properties, as it is particularly important for their usage in biomonitoring studies that use mosses. In this study, the kinetics of elemental sorption in three moss species (Pleurozium schreberi, Dicranum polysetum, and Sphagnum fallax) were investigated under laboratory conditions. Sorption from metal salt solutions was carried out under static conditions with decreasing elemental concentration. Functional groups responsible for binding metal cations to the internal structures of the mosses were also identified. It was shown that the equilibrium state was reached after about 60 min. Under the conditions of the experiment, in the first 10 min of the process, about 70.4-95.3% of metal ions were sorbed from the solution into the moss gametophytes by P. schreberi (57.1-89.0% by D. polysetum and 54.1-84.5% by S. fallax) with respect to the concentration of this analyte accumulated in the mosses at equilibrium. It can be assumed that the exposure of mosses with little contamination by heavy metals in an urbanized area under active biomonitoring will cause an increase in the concentration of these analytes in proportion to their concentration in atmospheric aerosols. In the case of P. schreberi and D. polysetum, the O-H/N-H band was enormously affected by the adsorption process. On the other hand, FTIR (Fourier transform infrared spectroscopy) analysis of S. fallax after adsorption showed slight changes for most of the bands analyzed. Based on this study, it can be concluded that mosses can be used as, for example, a biomonitor in monitoring of urban ecosystems, but also in the phytoremediation of surface waters.

BIOGENIC SYNTHESIS OF SILVER NANOPARTICLES FROM ASPERGILLUS ORYZAE MTCC 3107 AGAINST PLANT PATHOGENIC FUNGI SCLEROTINIA SCLEROTIORUM MTCC 8785

Phytopathogen including Sclerotinia sclerotiorum is a major problem for agricultural crops. Being safe, antifungal, and environment friendly, silver nanoparticles (AgNPs) are the first choices to combat phytopathogens. In view of this, the present study was designed to formulate AgNPs from Aspergillus oryzae MTCC No. 3107. Biosynthesis of AgNPs by A. oryzae was investigated using cell-free filtrates from fungi cultivated in potato dextrose broth (PDB) and amylase production media (APM). Fungal production media harbour inducers which upregulate secretion of specific enzymes. Amylase is known to catalyze the bio-reduction process. The cell- free filtrates containing extracellularly secreted fungal amylases when exposed to the metal salt solution (silver nitrate) at 1mM concentration, silver ions were reduced to zero oxidation state forming stable nano silver. The colour change was observed and the formation of AgNPs was further characterised by UV–vis spectrophotometry by scanning from 300-700 nm wavelength. Transmission electron microscope characterization revealed a size of 40nm. Further, the FTIR analysis identified the key functional groups involved in the stabilization and capping of AgNPs. Moreover, XRD analysis was done to identify the diffraction pattern in AgNPs. Antifungal effect of synthesized AgNPs on phytopathogen S. sclerotiorum MTCC 8785 was studied using variable concentrations of amylase mediated AgNPs. 100 percent inhibition was observed at 100 μg/ml concentration when compared to positive control.

Homogeneous precipitation of Mg/Al layered double hydroxide from concentrated metal salt solution under hydrothermal conditions

Homogeneous precipitation using urea hydrolysis under hydrothermal conditions has been examined to prepare carbonate type magnesium aluminium layered double hydroxides (Mg/Al-CO3 LDHs). To obtain well-crystallized Mg/Al-CO3 LDHs as single phase, low concentration starting solutions have been used, resulting in the small amount of product from a batch. In this study, concentrated starting solution of magnesium chloride and aluminum chloride (total metal salts concentration of 1.0 ​M) was used to achieve bulk syntheses. The reaction conditions were optimized to obtain well-crystallized Mg/Al-CO3 LDH of rosette-like shape with the radius of ca. 2–4 ​μm in a large scale (7.6 ​g from 160 ​mL container). The parameters including heating rate and reaction temperature were found to be important to avoid the formation of by-products, and the Mg/Al ratio in the initial solution influenced the composition and morphology of the products. The heating rate of 8 ​°C/min and the reaction temperature at 100oC successfully led to single-phase Mg/Al LDHs.

3D-printed solar evaporator with seashell ornamentation-inspired structure for zero liquid discharge desalination

Solar-driven interfacial evaporation has enormous promise for fresh water recovery and salt harvesting, but salt accumulation-related challenges stand in its way. Herein, we report a spined groove-ridge pairs inspired by the shell ornamentation of the Vasticardium vertebratum, which addresses salt accumulation by artfully integrating salt reflux into localized salt crystallization. The seashell-mimetic radial V-groove array enables the 3D evaporator to transport water rapidly and directionally, resulting in high-performance water evaporation (∼95% efficiency) and localized crystallization. The periodic spines enlightened by the spine-bearing ridge on the seashell provide considerable micro-unit salt reflux. The 2-in-1 integration design endows the three-dimensional evaporator with superior solar-driven zero liquid discharge and excellent long-term salt resistance even when dealing with high-salinity brine (20 wt% NaCl) and a series of heavy metallic salt solutions. Our design offers a new alternative solution to avoiding salt scaling and could advance locally crystallized solar evaporators towards practical applications.

Study on the Adsorption Mechanism of Cobalt and Nickel in Manganese Sulfate by δ-MnO2.

Manganese has excellent performance in removing metal ions from aqueous solutions, but there are few studies on the adsorption and removal of heavy metal impurities in metal salt solutions. In this paper, the adsorption of cobalt and nickel ions in MnSO4 solution by δ-MnO2 prepared from two different manganese sources was studied. The optimum adsorption conditions were as follows: When the concentration of Mn2+ was 20 g/L, δ-MnO2 addition was 10 g/L, Co2+ concentration was 80 mg/L, Ni2+ concentration was 80 mg/L, reaction time was 60 min, reaction temperature was 80 °C, and pH value was 7, the adsorption rate of Co2+ and Ni2+ reached more than 80%. The manganese dioxide adsorbed by heavy metals was analyzed and detected. The results showed that MnOOH appeared in the phases of both kinds of δ-MnO2, and their morphologies were dense rod-like structures with different lengths and flake-like structures of fine particles. Co and Ni were distributed on the surface and gap of MnO2 particles, and the atomic percentage of Co was slightly higher than that of Ni. The new vibration peaks appeared near wave numbers of 2668.32, 1401.00, and 2052.19 cm–1, which were caused by the complexation of cations such as Co2 + and Ni2 + with hydroxyl groups. Some cobalt and nickel appeared on the surface of δ-MnO2, and the surface oxygen increased after adsorption. The above characterization revealed that the adsorption of cobalt and nickel in manganese sulfate by δ-MnO2 was realized by the reaction of its surface hydroxyl with metal ions (M) to form ≡SOMOH.

(Digital Presentation) Theoretical Investigation of the Structure and Physico-Chemical Properties of Alkali Metal Perchlorate Solutions in Sulfolan

Next-generation batteries based on Na and K, which are alkali metals common in the earth's crust are considered promising alternatives to lithium-ion batteries in future energy storage and storage systems.Sulfur-containing compounds, such as sulfolane and its derivatives, are currently considered as promising solvents for use in lithium and post-lithium-ion batteries. However, the properties of alkali metal salts solutions in sulfolane are poorly understood.The aim of our work was to study the physicochemical properties of solutions of alkali metal perchlorates in sulfolane and intermolecular interactions in solutions (cation-solvent molecules, cation-anion) using the molecular dynamics method.In our work we used the OPLSaa non-polarizable force field. The molar ratio of salt and solvent was 1:20 (~0.5 M) in solutions of ClO4 - salts of Li, Na, K in sulfolane (SL). The calculations were carried out in the same way as in the work 1.The results of calculating the physicochemical properties of MeClO4 solutions in SL are summarized in Table. The calculated density values of LiClO4/SL and NaClO4/SL systems differ from those measured experimentally 2,3 by less than 0.6% (Table). It can be assumed that the calculated value of the density of the KClO4/SL solution is also close to the measured value. The calculated values of the specific electrical conductivity of LiClO4/SL and NaClO4/SL exceed the experimentally measured values by 2.5 and 1.3 times, correspondently. The overestimated calculated values can be explained by a strong simplification of the Nernst–Einstein relation which takes into account only cations and anions motion, and doesn’t take into account the motion of ion associates.The calculated transfer numbers of cations in MeClO4/SL are about 0.4.There are two peaks on the RDF curves of SL oxygen atoms around Li+, Na+, K+ (g(O(SL)-Me)): the first – clearly narrow and the second – broadened (Figure). The difference between the positions of the peak maxima (0.23 nm) is comparable to the distance between oxygen atoms in the SL (0.256 nm). Thus, the second broadened peak in the g(O(SL)–Me) curves is due to the second oxygen atom of the same SL molecule. The probability of Me+ solvation by the first or second oxygen atom of SL is the same. This is confirmed by the coincidence of the integral curves N(O(SL)-Me) of SL oxygen atoms around Me+ (Figure).There is one narrow clear peak on the RDF curves of the sulfur atom of SL around the cation g(S(SL)-Me). The maximum position is shifted relative to the maximum position of the RDF Me-O by 0.14 nm. It is comparable to S-O bond length (0.13 nm)) (Figure). Thus, the cation interacts with one oxygen atom of SL while the second oxygen atom doesn’t participate in the cation solvation and is turned in the opposite direction from it.There are two peaks on the RDF curves of the oxygen atoms of the ClO4 - around the cation g(O(ClO4 -)-Me): the first - clearly narrow and the second - broadened. The location of the first peak relative to the cation corresponds to the first solvation shell of the cations (Figure 1). The height of the first peak is significantly lower than the height of the peak on g(O(SL)-Me) curve. This indicates a low probability of the ClO4 - entering the first solvation shell of cations under the studied conditions (MeClO4/SL = 1:20, 303 K, 1 atm). Preferably, the ClO4 - is located in the outer coordination sphere of the solvate complex.Coordination numbers (CN) of metal cations were calculated based on the integral curves of RDF. The sum of the CN for the oxygen atoms of SL corresponds to the calculated CN of cations for the sulfur atom of SL. This indicates that SL is coordinated with the Li+, Na+, K+ by one oxygen atom.The coordination numbers of the Li+ < Na+ < K+ cations increase in the series 4.5 < 5.4 < 5.6 for SL and 0 < 0.1 = 0.1 for the ClO4 -, correspondently.The work was carried out within the framework of the theme of state assignment No. 21111900148-3. Reference Yamaguchi T., Yamada H., Fujiwara T. and Hori K. 2020 Mol. Liq. 312 113288Dokko K., Watanabe D., Ugata Y., Thomas M. L., Tsuzuki S., Shinoda W., Hashimoto K., Ueno K., Umebayashi Y. and Watanabe M. 2018 Phys. Chem. B. 122 47Sheina L.V., Karaseva E.V. and Kolosnitsyn V.S. 2021 J. Phys. Chem. A. 95 5 Figure 1

Liquid-phase temperature in the SpraySyn flame measured by two-color laser-induced fluorescence thermometry and simulated by LES

In the SpraySyn burner (Schneider et al., 2019) a solution of metal salts in a combustible liquid is atomized in a two-fluid nozzle with molecular oxygen as dispersion gas to generate oxide nanoparticles via combustion synthesis. The flame is anchored by a methane (CH4)/oxygen (O2) premixed flat flame stabilized on a porous plate surrounding the spray nozzle. This burner features a standardized design with simple geometry, which provides well-defined boundary conditions for the simulation to support model development and the interaction between experiment and simulation. In this work, two-color laser-induced fluorescence (2cLIF) thermometry based on the fluorescence tracer coumarin 152 dissolved in ethanol is applied to provide temporally averaged but spatially resolved liquid-phase temperature maps. The operating conditions for the spray formation were modified by varying the injection rate and the dispersion gas flow. Liquid-phase temperatures were predicted by large-eddy simulation (LES), where the spray is modeled by a Eulerian-Lagrangian approach based on measured liquid droplet properties (initial liquid-phase temperature, droplet size, and velocity distribution). Droplet size and velocity were measured by phase-Doppler anemometry (PDA). Gas-phase turbulent combustion is modeled with the flamelet-generated manifold (FGM) approach. Droplet temperature distributions were provided by the simulation to assess the systematic measurement error caused by LIF-signal averaging. Experimental and simulated average liquid-phase temperature maps are compared. The simulation results were found to be in good agreement with the experiment by showing a suitable prediction of the droplet heat-up process within the experimentally probed spray region.

Determination of hemoglobin-derived advanced glycation end products deploying metal salts in solution: Towards development of low-cost detection technique

The elevated blood sugar in Type II diabetes results in protein glycation that leads to the formation of Advanced Glycation Endproducts (AGEs) and cause severe pathogenic complications such as cardiovascular diseases, nephropathies, retinopathies, neurodegenerative diseases, etc. In our earlier work we have shown that gold nanoparticles (AuNPs) can be synthesized both in presence and absence of external reducing agent by in vitro generated AGEs from Hemoglobin A0 (HbA0). In the current work we have found that these highly reactive Hb derived AGEs (Hb-AGEs) are also capable of reducing silver ions and synthesize silver nanoparticles (AgNPs) with a different plasmonic response than the control solutions. It was observed that the concentration of AGE and metal salts play a vital role in the formation of nanoparticles and time-dependent stabilization of the particles. The lowest detection limit (LOD) showed that the reactions are highly sensitive because as low as 1 ng/μl of AGEs can be detected. When reduction of the two metal ions (Au 3 + and Ag + ) were compared it was found that the AuNPs could be a better choice for the colorimetric sensing due to the appearance of plasmon in the visible range, while AgNPs could serve as a cost-effective determinant of AGEs. Therefore, in conclusion we confirm that AGEs can be detected just by deploying metal salts in solution.

Metal complexes of benzimidazole-derived as potential anti-cancer agents: synthesis, characterization, combined experimental and computational studies.

In this study, a series of 14 Cu (II), Zn (II), Ni (II) and Ag (I) complexes containing bis-benzimidazole derivatives were successfully designed and synthesized from 2-(1H-benzimidazole-2-yl)-phenol derivatives and corresponding metal salt solutions. The compound structures were identified by FT-IR, 1H-NMR, powder X-ray diffraction and ESI-MS analyses, and the presence of the metal in the complexes was confirmed by ultraviolet-visible spectroscopy and ICP optical emission spectrometry. Electronic structure calculations were also carried out to describe the detailed structures in addition to the electronic absorption spectra of the ligands. The cytotoxic activity of the complexes was evaluated against three human cancer cell lines: lung (A549), breast (MDA-MB-231) and prostate (PC3) cancer cells. All complexes inhibited anti-proliferative cancer cells better than free ligands, especially Zn (II) and Ag (I) complexes, which are most sensitive to MDA-MB-231 cells. In addition, showing the growth inhibition of three cancer cell lines with IC50 < 10.4 µM, complexes C1, C3 and C14 could be considered potential multi-targeted anti-cancer agents.

Leather waste as precursor to prepare bifunctional catalyst for alkaline and neutral zinc-air batteries

Carbon materials derived from biomass waste are considered as potential electrocatalysts for applications in zinc-air batteries (ZABs) due to their low cost and good catalytic activity. Here, we reported the preparation of gel-based catalysts through utilizing hydrolyzed waste leather powder cross-linked with metallic salt solutions. After calcination, iron-nickel alloy anchored in nitrogen-doped porous carbon catalysts (FeNi@NDC) was achieved. Compared with commercial Pt/C catalyst, FeNi@NDC-800 exhibited lower E1/2 (0.77 V) and better durability. More importantly, the resulting FeNi@NDC-800-based alkaline ZABs achieved power density of 93.01 mW/cm2 and open circuit voltage of 1.45 V, which the FeNi@NDC-800-based neutral ZAB displayed a charge/discharge cycle stability of 275 h. This work opens up the possibility of rational design and preparation of low-cost and high-performance electrocatalysts from recyclable leather waste.

Formation and Dynamic Behavior of Macroscopic Aluminum-Based Silica Gardens.

Chemical gardens are self-assembled structures with intricate plant-like morphologies and consist of mineralized membranes, which form spontaneously at interfaces between compartments with dissimilar chemical composition, most typically acidic metal salt and alkaline sodium silicate solutions. While this phenomenon is thought to occur in a number of practical settings, it has also proven to be valuable for investigating transport characteristics in distinct applied systems. For example, coupled diffusion and precipitation processes were monitored in silica gardens based on calcium and iron salts, considered to be models for cement hydration and steel corrosion, respectively. Here we extend these studies to the case of aluminum-based silica gardens, one of the so far less frequently investigated examples of silica gardens. To this end, single macroscopic tubes were prepared in a reproducible way by the controlled addition of sodium silicate solution to a pellet of pressed aluminum nitrate. Continued sampling of the volumes enclosed by and surrounding the formed membraneous structure allowed the time-dependent development of ion concentration gradients to be tracked over extended periods of time, while both the pH and electrochemical potential differences across the membrane were recorded online by immersed probes. The dynamic behavior revealed in this way was finally complemented by ex-situ analyses of the composition of the formed tubes. The collected data shows that the as-prepared tubular structures consist of sodium aluminosilicate phases with certain similarities to zeolites and geopolymers. The emerging tube wall was further found to be permeable to all ionic species present in the system, allowing significant electrochemical potential to be sustained over tens of hours until diffusion had eventually diminished the initially generated gradients. The findings of this work may have important implications for the geochemical fate of natural aluminosilicate sources, the use of such geopolymers in construction applications, and the synthesis and properties of zeolites.

Highly sensitive detection of H2S gas at low temperature based on ZnCo2O4 microtube sensors

It is extremely necessary to detect Hydrogen sulfide (H2S) due to the hazardous nature. Thus, it is required to design a material which can detect H2S gas at low temperature. In this work, ZnCo2O4 microtubes are prepared by using absorbent cotton as template, combining immersion method in metal salt solution (Zn:Co=1:2) with calcination treatment in air. The influence of calcination temperature on the particle size and sensing property was also discussed. The diameter of particles on the ZnCo2O4 microtubes increases with increasing calcination temperature. The hollow microtubes of ZnCo2O4 materials calcined at 600 °C (ZCO-600) exhibit superb sensing performance to H2S at 90 °C with the lowest detection limit of 50 ppb. The optimum operating temperature (90 °C) was lower than the other reported ZnCo2O4 sensors. ZCO-600 sensor also shows excellent selectivity, repeatability, stability, humidity resistance and the good linear relationship in ppb and ppm level H2S. In addition, the feasible sensing mechanism of ZCO-600 to H2S is explored on the basis of XPS analysis. Thus, ZnCo2O4 as a sensing material possesses widespread application prospects for the detection of trace H2S gas.

Microwave Plasma-Enhanced Parylene-Metal Multilayer Design from Metal Salts.

In this paper, a new approach for the synthesis of Parylene–metal multilayers was examined. The metal layers were derived from a metal salt solution in methanol and a post-drying plasma reduction treatment. This process was designed as a one-pot synthesis, which needs a very low amount of resources and energy compared with those using electron beam sputtering processes. The Parylene coatings were obtained after reduction plasma treatments with Parylene C. Therefore, a Parylene coating device with an included plasma microwave generator was used to ensure the character of a one-pot synthesis. This process provided ultra-thin metal salt layers in the range of 1–2 nm for layer thickness and 10–30 nm for larger metal salt agglomerates all over the metal salt layer. The Parylene layers were obtained with thicknesses between approx. 4.5 and 4.7 µm from ellipsometric measurements and 5.7–6.3 µm measured by white light reflectometry. Tensile strength analysis showed an orthogonal pulling stress resistance of around 4500 N. A surface roughness of 4–8 nm for the metal layers, as well as 20–29 nm for the Parylene outer layer, were measured. The wettability for non-polar liquids with a contact angle of 30° was better than for polar liquids, such as water, achieving 87° on the Parylene C surfaces.

Structural evolution and photoluminescence properties of hybrid antimony halides

Low-dimensional hybrid antimony halide perovskites have fascinated the extensive research for their excellent photoluminescence behaviors. However, reasonable optimization of luminescence performance through molecule-level structural regulation remains a formidable challenge. The solution evaporation method with the reaction of organic amines and acid solutions of metal salts is a well-established method for the synthetic of low-dimensional hybrid antimony halide. In this work, by selecting organic cations with different sizes as template molecules, we have successfully synthesized three hybrid antimony halides of 0D [HDBA]2SbCl5 (1), 0D [H2ATMP]2SbCl7 (2) and 1D [H3PMDETA]Sb2Cl9 (3) (DBA ​= ​dibutylamine, ATMP ​= ​4-amino-2,2,6,6-tetramethylpiperidine, PMDETA = N,N,N′,N″,N″-pentamethyldiethylenetriamine). by the solution evaporation method at room temperature for 2–5 days. These hybrid antimony halides exhibit broadband yellow-light with the highest photoluminescence quantum yield (PLQY) of 8.38%. According to detailed spectroscopy characterizations and theoretical calculations, the broadband light emissions should originate from self-trapped excitons (STEs). These antimony halides could be fabricated as white LEDs with highest color rendering index (>90%). The intrinsic broad-band light emissions and facile assembly process enable these hybrid antimony halides as promising candidates for yellow-light emitting materials.