Oxide Chloride Research Articles

Inside Back Cover: Organocatalytic Lithium Chloride Oxidation by Covalent Organic Frameworks for Rechargeable Lithium‐Chlorine Batteries (Angew. Chem. Int. Ed. 7/2024)

Inside Back Cover: Organocatalytic Lithium Chloride Oxidation by Covalent Organic Frameworks for Rechargeable Lithium‐Chlorine Batteries (Angew. Chem. Int. Ed. 7/2024)

Hierarchical ZSM-5 zeolite supported RuOx catalysts via organic mesoporous porogens for catalytic oxidation of vinyl chloride

Hierarchical ZSM-5 zeolites supported RuOx catalysts were prepared via the addition of various organic mesoporous porogens (namely starch, cellulose and sucrose) for catalytic oxidation of vinyl chloride (VC). The usage of mesoporous porogens during catalysts preparation was favorable for boosting the catalytic activity of the resultant catalysts, and 1%RuOx/HZ5-10%sucrose exhibited the optimum catalytic activity, impressive catalytic stability and long-term durability. The structure-activity dependence from catalysts characterizations revealed that the higher specific surface area, more abundant strong acid sites and surface adsorbed oxygen species were regarded as the critical parameters for the noticeable improvement of catalytic activity. Based on in situ infrared spectroscopy analysis, 1%RuOx/HZ5-10%sucrose exhibited higher adsorption capacity and more efficient conversion of VC molecules with fewer formation of organic intermediates because of its superior catalytic activity in comparison with the single 1%RuOx/HZ5. Additionally, enol and carboxylate species were demonstrated to be the key organic intermediates in catalytic VC oxidation.

Acute toxicity and bioaccumulation of common urban metals in Bombus impatiens life stages

Metal contamination is ubiquitous in urban areas and represents a risk to arthropod species. Bees are exposed to metals while foraging within contaminated landscapes from multiple sources. Eliminating the risk of bee exposure to metals is complex, and requires an understanding of how bees become contaminated, how metals accumulate within bee bodies, and how this exposure influences their health. We selected Bombus impatiens, the common eastern bumble bee, as our focal species because it is the most frequently encountered bumble bee species in the eastern United States and common within urban greenspaces. The aims of this study were to quantify the lethal concentration exposure limit (LC50) for B. impatiens foragers, assess the bioaccumulation ability of environmentally relevant concentrations of common urban metals in adults, larvae, and pupae, and compare the LC50 values against field relevant concentrations collected by foraging bumble bees within a legacy city. Bumble bees were orally exposed to arsenic oxide, cadmium chloride, or chromium oxide in sucrose solution to encourage consumption. The LC50 for arsenic (As2O3 36.4 mg/L), cadmium (CdCl2 10.3 mg/L), and chromium (CrO3 189.6 mg/L) are 202×, 79×, and 1459× greater than concentrations found within urban bumble bee collected provisions, respectively. Adult bumble bees fed field realistic concentrations of metals accumulate significant amounts of cadmium and lead within their bodies, but do not accumulate chromium and arsenic. Additionally, adults accumulate significantly higher concentrations of metals than brood. While bumble bee foragers are unlikely to encounter lethal metal concentrations while foraging in contaminated landscapes, it is crucial to consider and understand how sublethal concentrations impact overall colony functioning. The results from this study highlight the need to identify hazards and bioaccumulation ability of common metals as bees respond differently to each metal species, as well as the impacts of metal mixtures on bioaccumulation and toxicity.

Comparative bio-effect of gadolinium with alternative contrast medium of magnesium chloride and zinc oxide nanoparticles on single-strand DNA following exposure to magnetic resonance imaging

Comparative bio-effect of gadolinium with alternative contrast medium of magnesium chloride and zinc oxide nanoparticles on single-strand DNA following exposure to magnetic resonance imaging

Nanostructured porous WO3 for photoelectrochemical splitting of seawater

Seawater, due to its salinity, can serve as an electrolyte in photoelectrochemical (PEC) systems, which have the potential to enable solar-driven production of hydrogen and oxidizing species. In this study several micrometer thick and highly porous nanostructured WO3 films were formed and their performance in photoanodic oxidation of chloride and sulfate ions, the most abundant anionic species in seawater, was investigated. Layers were characterized using scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, and BET surface area measurements. The study demonstrates that efficient PEC performance is achieved through optimal light absorption by sufficiently thick WO3 layers (3–5 μm), a highly porous structure that facilitates electrolyte permeation and ionic transport and provides a large electrochemically active interfacial area, and a nanosheet morphology where the sheet thickness is shorter than the hole diffusion length in WO3. The Faradaic efficiency of ClO- + ClO2- generation in neutral chloride-based electrolytes was found to be close to 100 %, but decreased significantly with photoelectrolysis time, presumably, due to the formation of higher chlorine oxo compounds. In addition, photocurrent stability and dissolution of WO3 photoanodes in acidic sulfate and neutral chloride media was compared. Though dissolution of WO3 in 0.5 M NaCl was found to be up to 3 times higher, photocurrent decay was more significant in 0.5 M H2SO4. The phenomenon was attributed to effective hole scavenging by surface-adsorbed Cl- ions, which prevents passivation of the photoelectrode surface due to formation of W(VI) peroxospecies.

Advancing carbon dioxide capture: investigation into the kinetics and efficiency of absorption in molten calcium oxide–chloride

The molten mixture of CaCl2 + CaO is capable of selective capture of CO2 with the absorption rate following almost exactly a novel kinetic model.

ELECTROCHEMICAL PRODUCTION OF TUNGSTEN: STATUS AND PROSPECTS

An overview of studies of the electroche­mical reduction of tungsten compounds of different composition in various reaction media is presented. It is shown that among the variety of existing scientific and technical methods for obtaining tungsten, there are attractive prospects for the creation and development of a new industrial process that would ensure the direct electrochemical release of oxygen from its oxygen-containing compounds into molten mixtures based on chloride and calcium oxide. This scientific and technical solution is known in the literature as the FFC Cambridge process (FFC process).In contrast to the known methods of electrochemical reduction of tungsten compounds, this process allows the reduction of oxygen-containing tungsten compounds in the solid state and does not depend on the course of acid-base equilibria at the electrode/electrolyte phase separation boundary. The most favorable conditions for the reduction of oxygen-containing tungsten compounds are provided by electrolysis using a liquid gallium cathode in both galvanostatic and potentiostatic modes, and it is advisable to use the initial tungsten compounds in a finely dispersed state. The electrochemical reduction of tungsten trioxide in thee utectic melt of sodium and calcium chlorides occurs through the intermediate stage of calcium tungstate formation, so it is advisable to use CaWO4 instead of WO3 as the starting compound for reduction. Electrochemical reduction on a liquid gallium cathode in a molten eutectic mixture of sodium and calcium chlorides allows obtaining highly dispersed tungsten powder (11–35 nm) of high purity (99.9%) with a degree of extraction of at least 90.0% from both tungsten trioxide and from calcium tungstate. In addition, in this way it is possible to obtain not only pure tungsten, but also metal alloys and composites based on it.

Ameliorative Effect of Galium Verum (Rubiaceae Family) Methanolic Extract on Folic Acid-induced Acute kidney Injury in Male Rats.

Background: Antioxidant, sedative, anticancer, and antibacterial properties are among the numerous pharmacological characteristics of Galium verum. Aim: The primary goal of this research was to investigate the therapeutic effects of G. verum extract against folic acid-induced acute kidney injury (AKI). Materials and methods: 18 male rats were assigned into three groups: Control, AKI, and G. verum. AKI was induced by a dose of folic acid (250 mg/kg, i.p.) while G. verum (250 mg/kg) was administrated for 7 consecutive days. Results: G. verum methanol extract contains flavonoids, anthraquinones, tannins, iridoids, triterpenes, steroids, phenols, and saponins, while it free of cardiac glycosides and alkaloids. G. verum extract significantly decreased levels of creatinine, urea, uric acid, sodium, chloride, potassium, microalbumin, malondialdehyde and nitric oxide while it increased creatinine clearance, glutathione reduced, and catalase levels. Meanwhile, histological examination of the kidney’s tissues revealed apparently normal structure. Conclusions: Underlying renal therapeutic mechanisms of G. verum action include a diuretic, antioxidant, and anti-inflammatory properties of G. verum extract resulting in improving kidney structure and enhance recovery of renal function.

Hydrogen Production with Seawater-Resilient Bipolar-Membrane Electrolyzers

Commercial proton exchange membrane water electrolyzers (PEMWEs) are highly efficient when operating in ultra-pure de-ionized water. However, introduction of additional ions leads to a reduction in device durability and efficiency. Chloride (Cl-) ions, typically found in high concentrations in seawater, lead to device performance issues driven in part by the chlorine evolution reaction at the anode. At the acidic anode-cation exchange layer interface, corrosive chlorine species (OCl-, HOCl, Cl-) are readily generated due to the facile kinetics of the 2-electron oxidation reaction relative to the desired 4-electron water oxidation reaction. Bipolar membrane water electrolyzers (BPMWEs), however, contain a locally basic anode-anion exchange layer interface, leading to improved thermodynamic favorability for O2 production rather than corrosive chlorine species production. Furthermore, the bipolar membrane can readily block anions and cations from accessing the desired reaction spaces. In this work, we evaluated ion transport, chloride oxidation, and durability of BPMWEs and PEMWEs operating in salt water. BPMWEs exhibit a low Faradaic efficiency of 0.005% for the oxidation of Cl− to corrosive chlorine species at the anode, compared to PEMWEs that can reach a Faradaic efficiency of up to 10% under similar conditions. In addition, BPMWEs demonstrate a device lifetime that is 140 times longer than that of PEMWEs operating in direct seawater electrolysis conditions. Failure modes for each membrane type have been investigated under both ultra-pure and impure water electrolysis conditions and are discussed in this work.

(Invited) The Internal Oxidation Mechanism of Ti60 Alloy in NaCl-coated Environment at 600o C

When serving in the marine environment, the blades of aircraft engines will suffer serious high-temperature corrosion and their service life will be shortened. This is because the water vapour and salt particles (mainly NaCl) in the marine atmosphere will inevitably be involved in the engine, resulting in severe corrosion of materials. Previous studies on the degradation of titanium alloy under NaCl mainly focused on the active oxidation mechanism, while the mechanism of internal oxidation, which can significantly damage the mechanical properties of the titanium, is not clear. In addition, internal oxidation appears microstructure sensitivity, indicating that microstructure design may be an important way to improve high-temperature corrosion resistance in the marine environment.Consequently, for further understanding the internal oxidation mechanism and the influence of microstructure on corrosion, the composition and morphology of the internal oxidized layer of the Ti60 samples, which corroded with NaCl precoated at 600 oC in moist O2 flow for 100 h, have been studied.According to the results, Ti2O formed within the internal oxidized layer. With the thermodynamic calculation results, this observation proves that internal oxides do not result from the oxidation of metal chlorides. As it is known that titanium has a high affinity to oxygen, the internal matrix turns into titanium oxides with different valence states directly, while TiCl4(g) formed from active oxidation further transports outward and is oxidized at the position with high P(O2).The α secondary phase, located inside the β phase, is more sensitive to NaCl-induced corrosion than the α lamellar outside the β phase. This is because β phase and phase boundaries provide more high-energy channels for corrosive media transport to the α secondary phase, which results in severe loss of metallic elements and oxidation. The design of the α secondary phase may be one essential point for developing titanium alloys with a good combination of mechanical properties and corrosion resistance in marine environments. Figure 1

Electrodeposited Sn-Cu-Ni alloys as lead-free solders on copper substrate using deep eutectic solvents: The influence of electrodeposition mode on the morphology, composition and corrosion behaviour

In this work we present the pulsed current (PC) electrodeposition of Sn-Cu-Ni alloy as lead-free solder candidate, from choline chloride – ethylene glycol eutectic mixtures (1:2 molar ratio) onto copper metallic substrates. Electrolytes containing Sn2+, Cu2+ and Ni2+ salts in the selected deep eutectic solvent have been considered. The effect of the applied frequency of PC on the morphology, composition and melting point of the alloy is discussed and compared to the ones obtained using direct current (DC) plating mode. A refinement of the grain size and lower melting temperature of the alloy were noticed when pulsed current was applied.A comparative analysis of the electrochemical corrosion behaviour at macro- and micro- scale has been performed in 0.5 M and 0.1 M NaCl solutions involving potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode (SVET) techniques. Furthermore, an analysis after 96 h of exposure to salt mist test simulating a corrosive attack in harsh environment is presented, too. The obtained results showed enhanced corrosion resistance of the ternary alloys electrodeposited under PC conditions (the best for 1.67 Hz frequency) as compared to those using DC. Additionally, Raman spectroscopy evidenced the presence of tin oxi/hydroxy chloride and tin oxides as surface corrosion products. A corrosion mechanism has been proposed.

Organocatalytic Lithium Chloride Oxidation by Covalent Organic Frameworks for Rechargeable Lithium‐Chlorine Batteries

AbstractRechargeable Li−Cl2 battery is a promising high energy density battery system. However, reasonable cycle life could only be achieved under low specific capacities due to the sluggish oxidation of LiCl to Cl2. Herein, we propose an amine‐functionalized covalent organic framework (COF) with catalytic activity, namely COF−NH2, that significantly decreases the oxidation barrier of LiCl and accelerates the oxidation kinetics of LiCl in Li−Cl2 cell. The resulting Li−Cl2 cell using COF−NH2 (Li−Cl2@COF−NH2) simultaneously exhibits low overpotential, ultrahigh discharge capacity up to 3500 mAh/g and a promoted utilization ratio of deposited LiCl at the first cycle (UR−LiCl) of 81.4 %, which is one of the highest reported values to date. Furthermore, the Li−Cl2@COF−NH2 cell could be stably cycled for over 200 cycles when operating at a capacity of 2000 mAh/g at −20 °C with a Coulombic efficiency (CE) of ≈100 % and a discharge plateau of 3.5 V. Our superior Li−Cl2 batteries enabled by organocatalyst enlighten an arena towards high‐energy storage applications.

Organocatalytic Lithium Chloride Oxidation by Covalent Organic Frameworks for Rechargeable Lithium-Chlorine Batteries.

Rechargeable Li-Cl2 battery is a promising high energy density battery system. However, reasonable cycle life could only be achieved under low specific capacities due to the sluggish oxidation of LiCl to Cl2 . Herein, we propose an amine-functionalized covalent organic framework (COF) with catalytic activity, namely COF-NH2 , that significantly decreases the oxidation barrier of LiCl and accelerates the oxidation kinetics of LiCl in Li-Cl2 cell. The resulting Li-Cl2 cell using COF-NH2 (Li-Cl2 @COF-NH2 ) simultaneously exhibits low overpotential, ultrahigh discharge capacity up to 3500 mAh/g and a promoted utilization ratio of deposited LiCl at the first cycle (UR-LiCl) of 81.4 %, which is one of the highest reported values to date. Furthermore, the Li-Cl2 @COF-NH2 cell could be stably cycled for over 200 cycles when operating at a capacity of 2000 mAh/g at -20 °C with a Coulombic efficiency (CE) of ≈100 % and a discharge plateau of 3.5 V. Our superior Li-Cl2 batteries enabled by organocatalyst enlighten an arena towards high-energy storage applications.

Electrochemical Synthesis of Rare-Earth Hexaborides in Chloride–Oxide Melts

Electrochemical Synthesis of Rare-Earth Hexaborides in Chloride–Oxide Melts

Advances in the improvement of photocatalytic activity of BiOCl nanomaterials under visible light

Abstract Photocatalysis is an effective way to alleviate the energy crisis and environmental pollution. Bismuth Chloride Oxide (BiOCl) is one of the most widely studied metal oxides due to its unique surface and electronic structure. However, the wide band gap of BiOCl and the high complexation rate of photogenerated electron–hole pairs limit its photocatalytic efficiency. Increasingly, efforts are being made to improve the performance of this range of photocatalysts. The article reviews the progress of research to enhance the photocatalytic activity of BiOCl nanomaterials. Strategies to improve the photocatalytic performance of single-phase BiOCl include morphological control, component adjustment, crystal facet control, and defects construction. Strategies to improve the photocatalytic activity of BiOCl-based composites include surface modification, immobilization of photocatalysts, impurity doping, and the construction of heterojunctions. In addition, the challenges and trends of BiOCl photocatalysts are discussed and summarized. Hopefully, this review will be helpful for the research and application of BiOCl photocatalysts.

Comparing the radiolytic oxidation of sulfur and chloride within ice on Europa and Mars

The surface of Europa is heavily irradiated by high-energy particles with the energy ranges of 1–100 MeV for primary electrons and ∼10 keV for secondary electrons. These irradiations may cause oxidation of surface materials, such as chlorides and sulfur-bearing species, through reactions with oxidative radicals formed by dissociation of H2O ice. Similar irradiation-induced oxidation could have occurred in near-surface ice on Mars. However, most of previous experiments simulated ∼10 keV electron irradiation onto ice materials on Europa and Mars, and few studies have investigated the oxidation of chlorides and sulfur by MeV electron irradiation. Here we performed laboratory experiments on MeV electron irradiation, as well as 10 keV electron and UV irradiations, onto mixtures of H2O ice and chlorides, or elemental sulfur, at low temperatures. Our experimental results indicate selective oxidation of sulfur against chlorides, with negligible formation of oxychlorides on irradiation of H2O ice and chloride mixtures, regardless of experimental conditions (temperature, electron energy, or presence of oxidants in ice). Sulfate is effectively formed by the electron irradiation. This selective oxidation may be caused by the different stabilities of atoms within irradiated H2O ice. If sulfate on Europa's surface is transported into the subsurface ocean, this could provide energy sources for possible chemoautotrophic life in the ocean. On Europa, sulfur would be one of key elements in redox chemistry on the surface and possibly in the subsurface ocean.

Preparation of High-Purity Lead Chloride and Lead Oxide from Spent Lead Paste by Crystallization

Preparation of High-Purity Lead Chloride and Lead Oxide from Spent Lead Paste by Crystallization

A robust & weak-nucleophilicity electrocatalyst with an inert response for chlorine ion oxidation in large-current seawater electrolysis

Seawater splitting into hydrogen, a promising technology, is seriously limited by the durability and tolerance of electrocatalysts for chlorine ions in seawater at large current densities due to chloride oxidation and corrosion. Here, we present a robust and weak-nucleophilicity nickel–iron hydroxide electrocatalyst with excellent selectivity for oxygen evolution and an inert response for chlorine ion oxidation which are key and highly desired for efficient seawater electrolysis. Such a weak-nucleophilicity electrocatalyst can well match with strong-nucleophilicity OH− compared with the weak-nucleophilicity Cl−, resultantly, the oxidation of OH− in electrolyte can be more easily achieved relative to chlorine ion oxidation, confirmed by ethylenediaminetetraacetic acid disodium probing test. Further, no strongly corrosive hypochlorite is produced when the operating voltage reaches about 2.1 V vs. RHE, a potential that is far beyond the thermodynamic potential of chlorine ion oxidation. This concept and approach to reasonably designing weak-nucleophilicity electrocatalysts that can greatly avoid chlorine ion oxidation under alkaline seawater environments can push forward the seawater electrolysis technology and also accelerate the development of green hydrogen technique.

Iron-doped cobalt nitride as an efficient electrocatalyst towards energy saving hydrazine assisted seawater splitting in near neutral to highly alkaline pH achieving industry level current density

Replacing sluggish anodic oxygen evolution reaction by hydrazine oxidation reaction in seawater electrolysis is one of the smartest ways of getting multiple benefits as it offers an energy saving route for hydrogen production keeping the cell voltage way smaller than responsible voltage for corrosive chloride oxidation. Here, we report iron-doped Co3N as highly active electrocatalyst towards hydrazine oxidation reaction and hydrogen evolution reaction in wide pH range of 7–14. The two-electrode electrolyser system reached industry scale current density of 1000 mA cm−2 at ultralow cell voltage of 0.65 V, and found sustainable at 500 mA cm−2 over 95 h in hydrazine assisted alkaline seawater splitting. The electrolyser system also achieved 200 mA cm−2 current density at 0.75 V in hydrazine assisted neutral seawater medium. Interestingly, a thin amorphous iron oxide layer formed in Fe-doped Co3N provided much needed protection during electrocatalysis offering long term stability at industry level current density.

Magnetic field induced transitions probed in CrOCl flakes using dynamic cantilever magnetometry

H −T phase diagrams for chromium oxide chloride (CrOCl) are usually obtained using data from the measurements of magnetization and specific heats. Recent works suggest that magnetic anisotropy exists in CrOCl. In this work, we use dynamic cantilever magnetometry, which is sensitive to both magnetization and magnetic anisotropy, to probe phase transitions in CrOCl flakes. Together with magnetization measurements from a Superconducting Quantum Interference Device, four major regions of the CrOCl H−T phase diagram along its c-axis are obtained, which is consistent with the previously reported works. Then, we studied magnetic field induced transitions in CrOCl flakes under four different temperatures. Several transitions in antiferromagnetic state and in incommensurate state, which have not been reported before, were recognized. We believe these transitions probably originate from magnetic anisotropy due to magnetoelastic coupling and lattice reconstruction in CrOCl. Our work provides intriguing experimental results on the intricate magnetic structure of CrOCl, making progress in understanding the rich magnetic states of CrOCl.