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Using the density-functional theory approach, including Hubbard U correction, we investigate the defect structures consisting of vanadium (V) atoms embedded in a monolayer silicene. Specifically, we consider V–V atom pairs in antiferromagnetic (AFM), ferromagnetic (FM), and non-magnetic states, which are embedded in substitutional and interstitial sites. We determine the ground-state structures, formation and binding energies, electronic structures, induced magnetization, as well as the spin-exchange coupling between the V–V pair. For the substitutional vanadium atom pair, the stability of the AFM and FM spin configurations depends on the sublattice sites in which the V atoms are sited. When the V pair is located on a similar sublattice site type, the AFM spin alignment is more energetically favored, whereas when the pair is located in a different sublattice site, the FM interactions are more stable. However, the relative stability of the AFM or FM configurations changes rapidly as the separation between the V pair increases. Regarding the interstitial-hole V–V pair configurations, the most stable structure is when the pair is at the nearest-neighbor hole sites and is in an FM alignment. Also, at larger separations, the AFM or FM hole configurations are approximately degenerate in energy. Furthermore, we elucidate on the Ruderman–Kittel–Kasuya–Yosida, direct-exchange, and the superexchange interaction mechanisms in the vanadium-embedded silicene. In addition, we estimate a Curie temperature (Tc) of up to ∼500 K for a silicene structure containing a V pair in the FM spin alignment. Such a high Tc, in addition to the stability of the material, suggests that vanadium-embedded silicene is a potential candidate material for spintronic device applications. [ABSTRACT FROM AUTHOR]

Various impurities have been doped into ferroelectric BaTiO3-based materials, which are used in multi-layer ceramic capacitors, to improve their insulation resistance, reliability, and dielectric properties. However, the relationship between doped impurities and these device properties at the microscopic level remains unexplored. This study investigated the charge states and solubilities of doped impurities (V, Cr, Mn, Fe, Mg, Ca, and Sr) in BaTiO3 using density functional theory. We employed the screened hybrid functional and a rhombohedral lattice model. Owing to a better description of unoccupied states with the hybrid functional, equilibrium charge states and magnetic moments of V, Mn, and Fe impurities were in good agreement with those measured by magnetic susceptibility measurements. Furthermore, impurity levels of transition metal elements were qualitatively consistent with the experimental reports obtained by electron paramagnetic resonance. However, levels of Fe calculated in cubic BaTiO3 did not reproduce those observations. Therefore, a dynamically stable rhombohedral lattice was found to be more suitable than a cubic lattice for calculating the defects in BaTiO3. The solubility of transition metal dopants was highly dependent on the oxygen chemical potential conditions. By analyzing the cohesive energy, we observed a lower (higher) equilibrium charge state of the defect compared with the higher (lower) oxidation number of stable competitive phase enhanced solubility under reducing (oxidizing) conditions. Our calculations revealed that vanadium and manganese dopants were soluble under reducing conditions owing to instabilities of their metal phases and act as effective acceptors in BaTiO3. [ABSTRACT FROM AUTHOR]

Various impurities have been doped into ferroelectric BaTiO3-based materials, which are used in multi-layer ceramic capacitors, to improve their insulation resistance, reliability, and dielectric properties. However, the relationship between doped impurities and these device properties at the microscopic level remains unexplored. This study investigated the charge states and solubilities of doped impurities (V, Cr, Mn, Fe, Mg, Ca, and Sr) in BaTiO3 using density functional theory. We employed the screened hybrid functional and a rhombohedral lattice model. Owing to a better description of unoccupied states with the hybrid functional, equilibrium charge states and magnetic moments of V, Mn, and Fe impurities were in good agreement with those measured by magnetic susceptibility measurements. Furthermore, impurity levels of transition metal elements were qualitatively consistent with the experimental reports obtained by electron paramagnetic resonance. However, levels of Fe calculated in cubic BaTiO3 did not reproduce those observations. Therefore, a dynamically stable rhombohedral lattice was found to be more suitable than a cubic lattice for calculating the defects in BaTiO3. The solubility of transition metal dopants was highly dependent on the oxygen chemical potential conditions. By analyzing the cohesive energy, we observed a lower (higher) equilibrium charge state of the defect compared with the higher (lower) oxidation number of stable competitive phase enhanced solubility under reducing (oxidizing) conditions. Our calculations revealed that vanadium and manganese dopants were soluble under reducing conditions owing to instabilities of their metal phases and act as effective acceptors in BaTiO3. [ABSTRACT FROM AUTHOR]

This study presents a novel implementation of vanadium dioxide (VO2) phase change material in an electromagnetic (EM) surface with beam steering capabilities. For the first time, we present the design, fabrication, and measurement of a globally actuated, VO2-based beamforming reflective EM surface. We propose a design featuring complementary unit cells that enable beam steering with a single excitation, marking a pioneering use of low-loss VO2 in creating a complementary EM surface for the mmWave band. The unit cells incorporating VO2 exhibit low-loss characteristics, with −0.92 and −1.9 dB in the hot state and −0.49 and −0.25 dB in the cold state, respectively. We incorporate both positive and negative phase variants alongside two temperature-independent phase unit cells. The complementary design enables us to utilize two beam operating states, effectively exploiting the otherwise unused cold state. We experimentally demonstrated beamforming at ±5° and ±10° from the broadside. In the case of ±10°, the measured gains at 35 GHz in the cold and hot states were 19.4 and 20.3 dB, respectively, which aligned well with the simulated gains of 20.9 and 21.5 dB. Manipulation of the electromagnetic wave direction with a single excitation has the potential for imaging, sensing, and communication applications. The complementary unit cell design methodology can be further adapted for mmWave beamforming, absorbing, and cloaking reconfigurable EM surfaces. Furthermore, the use of VO2 can be extended up to sub-THz frequencies due to the wideband, low-loss characteristics compared with conventional reconfigurable devices, such as PIN diodes or MEMS switches. [ABSTRACT FROM AUTHOR]

Constitutive models are essential for describing the mechanical behavior of materials under high temperatures and pressures, among which the Steinberg–Guinan (SG) model is widely adopted. Recent work has discovered a peculiar dual anomaly of compression-induced softening and heating-induced hardening in the elasticity of compressed vanadium [Phys. Rev. B 104, 134102 (2021)], which is beyond the capability of the SG model to describe. In this work, a modified SG elasticity constitutive model is proposed to embody such an anomalous behavior. Elemental vanadium is considered as an example to demonstrate the effectiveness of this improved model in describing the dual anomalies of elasticity. This new SG elasticity model can also be applied to other materials that present an irregular variation in the mechanical elasticity and are important to faithfully model and simulate the mechanical response of materials under extreme conditions. [ABSTRACT FROM AUTHOR]

Halogenated phenazine meroterpenoids are a structurally unusual family of marine actinobacterial natural products that exhibit antibiotic, antibiofilm, and cytotoxic bioactivities. Despite a lack of established phenazine halogenation biochemistry, genomic analysis of Streptomyces sp. CNZ-289, a prolific lavanducyanin and C2-halogenated derivative producer, suggested the involvement of vanadium-dependent haloperoxidases. We subsequently discovered lavanducyanin halogenase (LvcH), characterized it in vitro as a regioselective vanadium-dependent chloroperoxidase, and applied it in late-stage chemoenzymatic synthesis.

Understanding the protonation behavior of metal-oxo water oxidation catalysts is essential to improve catalyst efficiency and long-term performance, as well as to tune their properties for specific applications. In this work, we explore the basicity and protonation effects of the highly active water oxidation catalyst [(Mn4O4) (V4O13) (OAc)3]3− using density functional theory. We computed the relative free energies of protonation in a systematic fashion for all symmetry-inequivalent O atoms, where the presence of multiple oxidation states from Mn 4 IV to Mn 4 III and a rich Jahn–Teller isomerism adds a significant amount of complexity. For high oxidation states, the compound behaves like some other polyoxometalates, showing protonation preferably at the terminal and μ2-bridging O atoms of the vanadate cap. However, upon reduction, eventually, the protonation preference switches to the cubane O atoms, mostly driven by a strong increase in basicity for O atoms located along the Jahn–Teller axes. Our work further evidences that protonation can potentially lead to several chemical transformations, like disproportionation and charge transfer to vanadium, dissociation of ligands, or the opening of the cubane structure. Our simulated UV/Vis absorption spectra additionally provide valuable insights about how the protonation of the catalyst could be tracked experimentally. Overall, our analysis highlights the complexity involved in the protonation of heterometallic polyoxometalate clusters. [ABSTRACT FROM AUTHOR]

Optical emission spectroscopy studies of vanadium plasma in a cathodic-arc discharge in a nitrogen atmosphere have been carried out. Spectral lines of neutral atoms and ions of the cathode material V, V1+, and V2+, and nitrogen N2 and N2+ were observed in the discharge plasma. Analysis and comparison of the intensity of vanadium and nitrogen spectral lines as a function of nitrogen pressure showed that in vacuum excited ions V2+ and V+ are registered, with increasing pressure, the lines V+*, N2*, and N2+* are observed, and at pressures above 0.5 Pa, the neutral vanadium lines are additionally registered. The electron temperature of Te decreases from 5.9 to 3–4 eV with increasing pressure. Studies of cross-sectional scanning electron microscopy images of VN coatings deposited at different nitrogen pressures have shown that a dense, homogeneous, fine-grained microstructure is formed in the coating when the number of neutral V in the plasma is low, while in the presence of a large number of neutrals, the coating structure changes to a dense structure with columnar growth. [ABSTRACT FROM AUTHOR]

Photofragment spectroscopy is used to measure the vibrational spectra of V 2 + (CH 4) n (n = 1–4), V 3 + (CH 4) n (n = 1–3), and V x + (CH 4) (x = 4–8) in the C–H stretching region (2550–3100 cm−1). Spectra are measured by monitoring loss of CH4. The experimental spectra are compared to simulations at the B3LYP+D3/6-311++G(3df,3pd) level of theory to identify the geometry of the ions. Multi-reference configuration interaction with Davidson correction (MRCI+Q) calculations are also carried out on V 2 + and V 3 + . The methane binding orientation in V 2 + (CH 4) n (n = 1–4) evolves from η3 to η2 as more methane molecules are added. The IR spectra of metal-methane clusters can give information on the structure of metal clusters that may otherwise be hard to obtain from isolated clusters. For example, the V 3 + (CH 4) n (n = 1–3) experimental spectra show an additional peak as the second and third methane molecules are added to V 3 + , which indicates that the metal atoms are not equivalent. The V x + (CH 4) show a larger red shift in the symmetric C–H stretch for larger clusters with x = 5–8 than for the small clusters with x = 2, 3, indicating increased covalency in the interaction of larger vanadium clusters with methane. [ABSTRACT FROM AUTHOR]

Despite widespread interest in the phase-change applications of vanadium dioxide (VO2), the fabrication of high-quality VO2 thin films with elevated transition temperatures (TIMT) and high insulator–metal-transition resistance switching still remains a challenge. This study introduces a two-step atmospheric oxidation approach to fabricate bilayer VO2−x/VO2 films on a c-plane sapphire substrate. To quantify the impact of the VO2 buffer layer, a single-layer VO2 film of the same thickness was also fabricated. The bilayer VO2−x/VO2 films, wherein the top VO2−x film was under-oxidized, demonstrated an elevation in TIMT reaching ∼97 °C, one of the highest reported to date for VO2 films and is achieved in a doping-free manner. Our results also reveal a one-order increase in resistance switching, with the optimum bilayer VO2/VO2 film exhibiting ∼3.6 orders of switching from 25 to 110 °C, compared to the optimum single-layer VO2 reference film. This is accompanied by a one-order decrease in the on-state resistance in its metallic phase. The elevation in TIMT, coupled with increased strain extracted from the XRD characterization of the bilayer film, suggests the possibility of compressive strain along the c-axis. These VO2−x/VO2 films also demonstrate a significant change in the slope of their resistance vs temperature curves contrary to the conventional smooth transition. This feature was ascribed to the rutile/monoclinic quasi-heterostructure formed due to the top VO2−x film having a reduced TIMT. Our findings carry significant implications for both the lucid fabrication of VO2 thin film devices as well as the study of phase transitions in correlated oxides. [ABSTRACT FROM AUTHOR]

Understanding the trapping and diffusion mechanism of hydrogen in vanadium carbide (VC) precipitates is crucial for exploring the issue of hydrogen embrittlement in steel. Although there is widespread consensus that VC can trap hydrogen, the mechanism by which hydrogen diffuses into VC is still unclear. In this study, we used first-principles calculation methods to study the influence of different spacings of carbon vacancies on the trapping and diffusion of hydrogen in VC. The increase in the number of C vacancies makes it easier for vacancies to trap hydrogen, and hydrogen tend to fill up C vacancies. The diffusion of hydrogen into VC only occurs via neighboring C vacancies at a distance of 0.295 nm (connecting vacancies), leading to a diffusion barrier of 0.63–0.78 eV. This is consistent with experimental results and validates the experimental speculation that the diffusion of hydrogen in VC requires a connecting C vacancy grid. [Display omitted] • Connectivity of C vacancies is crucial for hydrogen trapping in VC precipitates. • Diffusion barrier of hydrogen in VC is 0.63–0.78 eV, consistent with experiments. • Electron gas channels enable hydrogen diffusion through adjacent C vacancies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heterostructures of the three-dimensional spindle shape were successfully synthesized. • Bimetallic sulfides driven by topological sulfidation of bimetallic MOFs. • DFT reveals electronic coupling at the atomic/orbital level. • Heterogeneous interfaces provide efficient electron tuning engineering. Rational design and preparation of a multiphase electrocatalyst for hydrogen evolution reaction (HER) has become a hot research topic, while applicable and pH versatility of vanadium tetrasulfide (VS 4) and heptairon octasulfide (Fe 7 S 8) composites have rarely been reported. Here, the facile topological sulfide self-template sacrifice method using FeV bimetallic MOFs is designed to obtain Fe 7 S 8 coupled with VS 4 heterostructures, enhancing the electron precipitation in the catalysts and attracts electrons to migrate. According to DFT simulations, the electronic coupling at the atomic orbital level and the modulation of interfacial electrons among various interfaces play a crucial role in enhancing the intermediate state process of the hydrogen evolution reaction (HER) across the entire pH range, promoting the optimal d-band centroid value (ε d). Reassuringly, the prepared 3D Fe 7 S 8 /VS 4 electrodes possessed excellent performances of η 10 = 53 mV, η 10 = 135 mV and η 10 = 38 mV in a conventional three-electrode configuration in a 1 M KOH, 1 M Na 2 SO 4 , and 0.5 M H 2 SO 4 , and the stabilized currents can all be maintained for 48 h. This innovative design of in situ heterostructured materials constructed from dual transition metal sulfides provides inspiring ideas for the preparation of all-pH catalysts. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) have been widely studied in aqueous zinc‐ion batteries (AZIBs) due to the characteristics of large specific surface area, open aperture, and straightforward synthesis. In this work, vanadium‐based PBA nanocubes were firstly prepared using a mild in situ conversion strategy at room temperature without the protection of noble gas. Benefiting from the multiple‐redox active sites of V3+/V4+, V4+/V5+, and Fe2+/Fe3+, the cathode exhibited an excellent discharge specific capacity of 200 mAh g−1 in AZIBs, which is much higher than those of other metal‐based PBAs nanocubes. To further improve the long‐term cycling stability of the V‐PBA cathode, a high concentration water‐in‐salt electrolyte (4.5 M ZnSO4+3 M Zn(OTf)2), and a water‐based eutectic electrolyte (5.55 M glucose+3 M Zn(OTf)2) were designed to successfully inhibit the dissolution of vanadium and improve the deposition of Zn2+ onto the zinc anode. More importantly, the assembled AZIBs maintained 55 % of their highest discharge specific capacity even after 10000 cycles at 10 A g−1 with superior rate capability. This study provides a new strategy for the preparation of pure PBA nanostructures and a new direction for enhancing the long‐term cycling stability of PBA‐based AZIBs at high current densities for industrialization prospects. [ABSTRACT FROM AUTHOR]

The exceptional synergy of ceramic and metallic properties within MAX phases positions them as highly promising for a wide array of applications. However, their stability has been threatened by the phenomenon of A-site metal whisker growth. Herein, we have significantly mitigated tin whisker growth in Ti 2 SnC by incorporating vanadium solutes at its M-site. With an increase in vanadium concentration, there is a marked reduction in the degree of decomposition of the M-site solid solution when subjected to the same level of externally destructive treatments, thereby inhibiting whisker proliferation. Both experimental outcomes and theoretical calculations reveal that the vanadium solid solution augments the hardness, Pugh's ratio, and Poisson's ratio of Ti 2 SnC, enhancing its mechanical strength and toughness. The incorporation of V atoms introduces stronger V–C and V–Sn bonds, as evidenced by its electronic density of states and bulk modulus, thus significantly bolstering the resistance of MAX phases against decomposition and effectively curtailing whisker growth. Additionally, the phenomenon reported in this paper also conforms to the electrostatic theory of whisker growth. This work for the first time achieves the suppression of A-site whisker growth through an M-site solid solution, thereby extending their potential for applications where durability and reliability are paramount. [ABSTRACT FROM AUTHOR]

Precise detection and analysis of trace elements in materials are critical for various industrial applications. This study integrates laser-induced breakdown spectroscopy (LIBS) with advanced machine learning algorithms—random forest (RF) and gradient boosting decision tree (GBDT)—to develop an ensemble model for the rapid quantitative prediction of vanadium (V) in petroleum coke. A 1064 nm laser was employed to ablate petroleum coke samples, generating plasma, with the resultant spectral data collected via a spectrometer. The spectral data underwent preprocessing to isolate vanadium-specific information. Optimization of the regression prediction parameters for RF and GBDT was achieved through a recursive feature elimination method. Subsequently, an ensemble model was constructed to predict vanadium concentration. The results indicate that the ensemble model demonstrates excellent predictive performance, with R2 = 0.99976, RMSECV = 3.47145 mg kg−1, and RMSEP = 3.38779 mg kg−1. Hence, integrating RF and GBDT with LIBS offers a robust and precise methodology for vanadium concentration detection and analysis, providing significant insights and methods for monitoring trace element concentrations in petroleum coke. [ABSTRACT FROM AUTHOR]

The oil ash radioactive waste was generated from electrical power plants and it was presented great concern due to environmental impact. In this study oil ash was characterized from technical and radiological aspects. Oil ash average activity concentrations for 226Ra, 232Th, and 40K were (1718 ± 85.9, 278.1 ± 13.9, and 136 ± 6.7) Bq/kg respectively, that were higher than the worldwide average. The average value of AEDtot was (10.5 ± 0.5) mSv/y, which was higher than the dose limit of public. All the radiological parameters were higher than worldwide. The samples examined by XRF, and XRD. That contained economic elements as iron, vanadium, nickel. [ABSTRACT FROM AUTHOR]

Vanadium is an extremely valuable industrial metal typically obtained from processing metallurgical slags. This article provides a comprehensive review and critical evaluation of the technologies of vanadium extraction from slags aiming to identify the most prospective technology. The review covers traditional approaches for treating V‐bearing slags, such as salt roasting followed by acid leaching and ammonium precipitation, as well as promising alternative methods in this field, such as bioleaching, ultrasound‐assisted leaching, and vaporization. The current industrial practice remains energy‐intensive and is associated with chemical waste generation, thus leaving room for further improvements. Overall, this work provides valuable insights into the recycling of vanadium from steelmaking slags including extraction efficiencies of industrial and lab‐scale methods, and discusses the advantages and disadvantages of each method setting the stage for future advancements in this field. The vaporization method is one of the most promising among those reviewed. [ABSTRACT FROM AUTHOR]

Vanadium is a critical metal that has been widely used in a broad variety of applications with almost no metal substitutes. However, the limited availability of its (vanadium) primary resources has raised concerns of supply security. In view of the criticality, recycling vanadium from secondary resources has been identified as a vital supply alternative. This article thus presents a comprehensive overview of metallurgical processes used in the recycling of vanadium from a variety of secondary resources, including spent HDS catalyst, spent SCR catalyst, fly ash, red mud, Bayer's sludge, alloy scrap, tailings, etc. First, the physicochemical characteristics of these secondary resources are emphasized. Understanding the characteristics of vanadium-bearing secondary resources is important as it determines the recycling route. The metallurgical recycling processes of vanadium, which include aqueous- and thermal processes are discussed in depth, along with the theoretical backgrounds and fundamentals of each process. Also discussed are the industrial-scale processes and trend in research and development (R&D) for the respective secondary resources. Besides highlighting the status of recycling processes, the article also provides prospective directions for such resources. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the possibility of using mechanical spectroscopy to determine the strength of tool coatings from their lifespan. Mechanical spectroscopy with the determination of the index tan δ (internal friction) was used as the research method. Samples were coated with lamellae composed of WC-6wt% Co cemented carbides. The specimens measured 1.0 mm, 3.0 mm, and 40.0 mm, created using a conventional industrial liquid phase sintering procedure. The original powder consisted of cobalt with traces of chromium and vanadium, and submicron WC grains. The tools tested included carbide cutting tools, and the workpieces were steel alloys. Comparative results showed that coated tools had significantly improved tool life and durability. The relationship between the coating and tool life was evident, providing a practical approach for predictive and non-destructive analyses of coatings on tool durability for composite and finely structured materials. [ABSTRACT FROM AUTHOR]

Background and Purpose: Metal‐based therapeutic agents are limited by the required concentration of metal‐based agents. Hereby, we determined if combination with 17β‐oestradiol (E2) could reduce such levels and the therapy still be effective in type 2 diabetes mellitus (T2DM). Experimental Approach: The metal‐based agent (vanadyl acetylacetonate [VAC])– 17β‐oestradiol (E2) combination is administered using the membrane‐permeable graphene quantum dots (GQD), the vehicle, to form the active GQD–E2–VAC complexes, which was characterized by fluorescence spectra, infrared spectra and X‐ray photoelectron spectroscopy. In db/db type 2 diabetic mice, the anti‐diabetic effects of GQD–E2–VAC complexes were evaluated using blood glucose levels, oral glucose tolerance test (OGTT), serum insulin levels, homeostasis model assessment (homeostasis model assessment of insulin resistance [HOMA‐IR] and homeostasis model assessment of β‐cell function [HOMA‐β]), histochemical assays and western blot. Key Results: In diabetic mice, GQD–E2–VAC complex had comprehensive anti‐diabetic effects, including control of hyperglycaemia, improved insulin sensitivity, correction of hyperinsulinaemia and prevention of β‐cell loss. Co‐regulation of thioredoxin interacting protein (TXNIP) activation by the combination of metal complex and 17β‐oestradiol contributed to the enhanced anti‐diabetic effects. Furthermore, a potent mitochondrial protective antioxidant, coniferaldehyde, significantly potentiates the protective effects of GQD–E2–VAC complexes. Conclusion and Implications: A metal complex–E2 combinatorial approach achieved simultaneously the protection of β cells and insulin enhancement at an unprecedented low dose, similar to the daily intake of dietary metals in vitamin supplements. This study demonstrates the positive effects of combination and multi‐modal therapies towards type 2 diabetes treatment. [ABSTRACT FROM AUTHOR]

The present study focuses on the effect of molybdenum and nitrogen on the microstructure and mechanical properties of VC x O y -Fe cermets. Samples with 0–23 at% Mo were fabricated using a wet synthesis route and heat treatment under Ar and N 2 atmospheres. Phase transformations during heating were investigated by TGA-DSC in combination with XRD, and the resulting materials were analyzed by SEM/EDX. A doping level of 6–12 at% was found to be optimal, as it lowered the melting point of the metallic binder to 1320–1360 °C. Replacing argon with nitrogen further decreased the melting point to 1210–1240 °C and reduced the grain size. Depending on the sintering temperature, gas environment, and molybdenum content, the produced cermets were characterized by 92–97 % density, 17–29 vol% binder phase, 8–14 GPa hardness, and 6–9 MPa m0.5 fracture toughness. The average size of oxycarbide grains, their stoichiometry, and the amount of dissolved vanadium in the iron binder demonstrated a strong correlation with changes in mechanical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: This study reports the preparation of 2‐hydroxy‐3‐(4‐(((2‐((2‐(((E)‐4‐(2‐hydroxy‐3‐(trimethylammonio)propoxy)‐3‐methoxybenzylidene)amino)ethyl)amino)ethyl)imino)methyl)‐2‐methoxyphenoxy)‐N,N,N‐trimethylpropan‐1‐aminium (HYM/QA). The adsorbent was employed to extract and concentrate vanadium from its solutions and boiler ash samples. Results: The impact of initial dosage, pH, reaction time and temperature on the sorption behavior of V(V) was examined. Under optimal conditions (pH 5, 0.08 g dose, 45 min at room temperature), a sorption capacity of 392.25 mg g−1 was achieved. The uptake of V(V) on HYM/QA was effectively reversed using 1 mol L−1 NaOH, regenerating the material. After six cycles of sorption and elution, the sorption capability remained at 91.4% of its initial value. The efficiency and selectivity of HYM/QA toward V5+ ions were assessed using the separation factor parameter, revealing limited interference from heavy metals such as Mn2+, Cr3+, Pb2+, Si4+, Al3+, NO32−, HCO3− and Zn2+. The uptake process of HYM/QA for V(V) conformed to the Langmuir and Dubinin–Radushkevich isotherm models and the pseudo‐second‐order kinetic model. HYM/QA was characterized by infrared, Brunauer–Emmett–Teller surface area, 1H NMR, 13C NMR and gas chromatography–mass spectrometry analyses, confirming successful preparation. Thermodynamic assessments suggested that the sorption process is endothermic, spontaneous and becoming more favorable with rising temperature. Conclusion: The optimized conditions were used to adsorb vanadium from boiler ash samples, and the obtained vanadium pentaoxide was analyzed and confirmed using various tools, demonstrating the material's effectiveness for vanadium extraction. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

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Calcium titanate (CaTiO3), a member of the perovskite family, is a multifunctional material with a wide range of uses, including photocatalytic wastewater treatment, electronic devices, lighting and display devices, biomedicine and many more. In this work, for the first time, the CaTiO3 nanoparticles (NPs) doped with different molar (0.2, 0.4, 0.6, and 0.8) percentages of Vanadium (V) were successfully synthesized via a Sol–gel method and used for the photocatalytic treatment of a wide range of wastewater. It is interesting to note that even after doping vanadium, the CaTiO3 crystal structure retained its perovskite structure, and the V-doped CaTiO3 displayed increased solar or visible light absorption with a band gap from 1.96 to 2.34 eV. Studies were conducted using XRD for phase formation, FESEM for morphology, EDX for structural composition, and UV–Vis for band gap. The percentage of Chemical Oxygen Demand (COD) removal was examined under sunlight at various irradiation times ranging from 2 to 8 h with a catalyst dose of 1 g/L and pH of 7.2 to examine the impact of Vanadium doping on the photocatalytic performance of CaTiO3. The percentage of COD removal from sewage treatment plant effluent, textile industry effluent, and landfill leachate was 98%, 94%, and 88% respectively using 0.4 mol% of V-doped CaTiO3. [ABSTRACT FROM AUTHOR]

Introduction: Vanadium is a widely used transition metal in industrial applications, but it also poses significant neurotoxic and environmental risks. Previous studies have shown that exposure to vanadium may lead to neurodegenerative diseases and neuropathic pain, raising concerns about its impact on human health and the ecosystem. To address vanadium neurotoxicity, through targeting NMDA glutamate and dopamine signaling, both involved in neurodegenerative disorders, shows promise. Using Caenorhabditis elegans as a model, we evaluated a novel compound with a mixed NMDA glutamate receptor-dopamine transporter pharmacology, ZA-II-05 and found it effectively ameliorated vanadium-induced neurotoxicity, suggesting a potential neuroprotective role. Methods: Synchronized young adult worms were assigned to four different experimental groups; Controls; 100 mM of Vanadium; Vanadium and 1 mg/ml ZA-II-05; and ZA-II-05 alone. These were examined with different markers, including DAPI, MitoTracker Green and MitoSox stains for assessment of nuclei and mitochondrial density and oxidative stress, respectively. Results: Exposure to vanadium in C. elegans resulted in decreased nuclear presence and reduction in mitochondrial content were also analyzed based on fluorescence in the pharyngeal region, signifying an increase in the production of reactive oxygen species, while vanadium co-treatment with ZA-II-05 caused a significant increase in nuclear presence and mitochondrial content. Discussion: Treatment with ZA-II-05 significantly preserved cellular integrity, exhibiting a reversal of the detrimental effects induced by vanadium by modulating and preserving the normal function of chemosensory neurons and downstream signaling pathways. This study provides valuable insights into the mechanisms of vanadium-induced neurotoxicity and offers perspectives for developing therapeutic interventions for neurodegenerative diseases related to environmental toxins. [ABSTRACT FROM AUTHOR]

The gradual capacity decrease of vanadium redox flow battery (VRFB) over long‐term charge‐discharge cycling is determined by electrolyte degradation. While it was initially believed that this degradation was solely caused by crossover, recent research suggests that oxidative imbalance induced by hydrogen evolution reaction (HER) also plays a significant role. In this work by using vanadium pentoxides with different impurities content, we prepared three grades of vanadium electrolyte. By measuring electrochemical properties on carbon felt electrode in three‐electrode cell and VRFB membrane‐electrode assembly we evaluate the influence of impurity content on battery polarization and rate of side reactions which is indicated by the increase of average oxidation state (AOS) during charge‐discharge tests and varies from 0.061 to 0.027 day−1 for electrolytes made from 99.1 and 99.9 wt % V2O5. We found that increase of AOS correlates with the increase of open‐circuit voltage of VRFB in the discharged state ranging from 9.6 to 14.9 mV day−1 for highest and lowest electrolyte purity levels, respectively. While AOS increase is significant, it does not solely determine capacity fade. It is demonstrated that the presence of vanadium crossover decreases capacity fade, i. e. levels the contribution of side reactions on capacity drop. [ABSTRACT FROM AUTHOR]

Vanadium pentoxide (V2O5) nanoparticles exhibit diverse properties and have been studied for a wide range of applications, including energy storage, catalysis, environmental remediation, and material enhancement. In this work, we have reported the synthesis of vanadium pentaoxide (V2O5) nanoparticles using hydrothermal method. Ammonium metavanadate (NH4VO3) was used as a source of vanadium. These syntheses were carried out at four different concentrations of vanadium source. The hydrothermal reaction was conducted at a temperature of 180 °C for a duration of 24 hours, followed by an additional 24 hours period of natural cooling. Four samples were annealed in air using a muffle furnace at 500 °C for five hours. The x-ray diffraction technique was used to study the structural aspects. A comparative analysis of the microstructure was conducted utilizing the Scherrer method, the Williamson–Hall method and its various models, size-strain analysis, and the Halder–Wagner method. The crystallite size and microstrain were determined using these distinct methods, revealing a systematic correlation between the crystallite size and microstrain obtained through the different techniques. [ABSTRACT FROM AUTHOR]

Complex formation of vanadium(V) with 4-(2',3',4'-trihydroxyphenyl)-3-nitro-5-sulfoazobenzene (R) in the presence of cationic surfactants (CS), cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), and cetyltrimethylammonium bromide (CTMABr), is studied. Vanadium(V) and R form a colored complex at a component ratio of 1 : 2 and pH of 5.0–5.5. The absorbance maximum of the complex is at 449 nm, while the reagent under these conditions absorbs light at 395 nm. In the presence of cationic surfactants, mixed-ligand complexes with a component ratio of V(V) : R : CS = 1 : 2 : 2 are formed, which results in a bathochromic shift of the absorbance maximum. Additionally, the pH value for the maximum complex formation shifts to a more acidic medium compared to the homoligand V(V)–R complex. The absorbance of the V(V) : R : CPCl, V(V): R : CPBr, and V(V) : R : CTMABr complexes is maximal at 457, 461, and 466 nm, respectively. The yield of these complexes is the highest at pH of 3.5–4.0 for VV(V) : R : CPCl and V(V): R : CPBr, and at a pH of 2.5–3.0 for V(V) : R : CTMABr. The formation of both homoligand and mixed-ligand vanadium(V) complexes depends on the reaction time, temperature, and concentrations of the reacting components. The determined stability constants indicate the high stability of the resulting mixed-ligand complexes. The specific conductivity of the complexes under the optimal conditions of complex formation was determined using conductometric titration. Calibration curves for the determination of vanadium(V) as homoligand and mixed-ligand complexes are linear. The effect of foreign ions and masking agents on the determination of V(V) as homoligand and mixed-ligand complexes was analyzed; it was shown that the presence of cationic surfactants significantly increases the selectivity of the reaction. An analysis of water samples from Lake Khanbulan, Lankaran District, Azerbaijan Republic using the developed procedure showed the presence of small amounts of vanadium(V). [ABSTRACT FROM AUTHOR]

BiVO4 has been widely concerned due to its great potential in photoelectrochemical (PEC) water splitting. However, low carrier mobilities and high recombination efficiency of photogenerated carriers impede its photocatalytic performance. Herein, an in situ PEC cyclic‐voltammetry‐induced surface reconstruction of BiVO4 photoanodes (BVO pristine) is developed with significantly enhanced efficiency for solar water splitting. A series of in situ characterizations (including in situ X‐ray diffraction, in situ Raman), together with electrochemical tests and density‐functional theory calculations, reveal that during the photoelectrical activation process, the BVO pristine surfaces undergo a crystal plane reconstruction with greatly increased {040} crystal face to promote the separation of photogenerated carriers. In addition, abundant vanadium vacancies and oxygen vacancies are also introduced into the BiVO4 surface during the crystal face reconstruction process with more favorable surface water adsorption and increased injection efficiency of photogenerated carriers. Therefore, the charge‐transfer resistance (Rct) between BVO pristine and electrolyte under AM 1.5G illumination substantially reduced from the original 15 200 to 2820 Ω after the activation. Moreover, the photocurrent density of activated BVO pristines increases more than 12 times, relative to the original BiVO4. In this work, a new horizon for in situ photoelectric activation of semiconductor photoelectrodes with significantly enhanced PEC water splitting is provided. [ABSTRACT FROM AUTHOR]

The FCC unit is closely related to its upstream and downstream units, especially for single series refineries, the change of the working condition of the upstream unit will have a significant impact on the production and operation of the downstream unit. During the catalyst replacement period of the residue hydrogenation unit, the FCC unit blended vacuum residue, resulting in severe deterioration of the properties of the FCC feedstock. The increase in vanadium content in the feedstock led to a decrease in the activity of the equilibrium catalyst and an increase in the olefin content of the FCC gasoline, causing rapid coking of heat exchanger group E101 in the S Zorb unit and affecting its operation. Therefore, during the catalyst replacement period of the residue hydrogenation unit, it is recommended to purchase light paraffin-base crude oil with low sulfur and metal content in advance, in order to alleviate the vanadium poisoning of the FCC unit catalyst; try to increase the catalyst consumption of the FCC unit to over 2.0 kg/t to prevent excessive vanadium content of the equilibrium catalyst; if E101 is rapidly coking and has caused excessive pressure drop, chemical cleaning can be used to clean the coking in the E101 tube pass. [ABSTRACT FROM AUTHOR]

Spent adsorbents for recycling as catalysts have drawn considerable attention due to their environmentally benign chemistry properties. However, traditional thermocatalytic strategies limit their applications. Here, we developed an enhanced photocatalytic strategy to expand the range of their applications. A magnetic chitosan/ZrO2 composites (MZT) for V(V) adsorption, which were prepared using chitosan, ZrO2 and Fe3O4 by one‐pot synthesis. The spent MZT as a catalyst was used to synthesize 2‐phenyl‐1H‐benzo[d]imidazole, yielding up to 89.7 %. It also was implemented to photocatalysis reactions for recycle. The discolored rates of rhodamine B (RhB) were 72.3 % and 97.4 % by new and spent MZT, respectively. The new and spent MZT showed the forbidden bands were 251 nm and 561 nm, respectively. The result displayed spent MZT red shifted to the cyan light region. The mechanism of catalysis also has been studied in detail. [ABSTRACT FROM AUTHOR]

The intrinsically sluggish sulfur reduction reaction kinetics and serious shuttle effect of soluble lithium polysulfides (LiPSs) severely impede the practical commercialization of lithium‐sulfur (Li‐S) batteries. Herein, self‐supported tungsten nitride and carbide heterostructures with vanadium doping that are directly grown on carbon cloth substrate (CC@V‐W2N/WC1‐x) are creatively designed for Li‐S batteries, which can tandemly catalyze the liquid–liquid conversion and liquid–solid conversion of polysulfide intermediate free of any interference from polymer binders and conductive additives. Noteworthy, the rich heterointerfaces and vanadium doping are beneficial for rapid charge transfer, strong chemical adsorption toward LiPSs, massive exposed catalytically active sites, and remarkable catalytic activities. Consequently, Li‐S batteries assembled with the CC@V‐W2N/WC1‐x/S cathodes exhibit high sulfur utilization, superior rate capability, and decent long‐term cycling stability. Furthermore, experimental analyses and theoretical calculations jointly substantiate that the V‐W2N component is more effective in catalyzing the conversion of long‐chain LiPSs, while the V‐WC1‐x benefits the favorable Li2S deposition kinetics. More importantly, the Li‐S pouch cells are also fabricated to demonstrate their feasibility for practical applications. This work not only highlights the significance of tandem catalysis on the consecutive conversion of LiPSs but also provides a feasible avenue for developing highly efficient electrocatalysts toward high‐performance Li‐S batteries. [ABSTRACT FROM AUTHOR]

Mussel byssus is an important model for bio-inspired design, due to the discovery that byssus proteins enriched in the non-canonical amino acid 3,4-dihydroxyphenylalanine (DOPA) form dynamic, load-bearing metal coordination cross-links. While it was initially assumed that cross-linking was based on DOPA–Fe coordination, recent findings challenge this assumption, suggesting that mussels preferentially utilize vanadium. Yet, the details are still unclear. Here, we performed a cross-disciplinary investigation of vanadium use by mussels for formation and function of the byssus, harnessing Raman and X-ray absorption spectroscopy, DFT modeling, and rheological studies. Our results indicate that Mytilus mussels actively uptake vanadium for the express purpose of incorporating it into the byssus, and that byssus V content is influenced by local seawater vanadium concentration. The vanadium oxidation state in the byssus appears to be a mixture of V(IV) and V(III), while the dominant coordination geometry is octahedral tris–DOPA–V. Rheological studies on model DOPA-enriched polymer hydrogels demonstrated that vanadium-reinforced gels exhibit more solid-like behavior than iron-reinforced gels at seawater pH, which may explain why mussels prefer vanadium for building their byssus. These findings offer new insights for how vanadium is used in biology, but also offer further inspiration for novel mussel-inspired adhesive, coatings, and supramolecular materials. [ABSTRACT FROM AUTHOR]

Exposure to certain heavy metals has been demonstrated to be associated with a higher risk of preterm birth (PTB). However, studies focused on the effects of other metal mixtures were limited. A nested case‒control study enrolling 94 PTB cases and 282 controls was conducted. Metallic elements were detected in maternal plasma collected in the first trimester using inductively coupled plasma‒mass spectrometry. The effect of maternal exposure on the risk of PTB was investigated using logistic regression, least absolute shrinkage and selection operator, restricted cubic spline (RCS), quantile g computation (QGC) and Bayesian kernel machine regression (BKMR). Vanadium (V) and arsenic (As) were positively associated with PTB risk in the logistic model, and V remains positively associated in the multi‐exposure logistic model. QGC analysis determined V (69.42%) and nickel (Ni) (70.30%) as the maximum positive and negative contributors to the PTB risk, respectively. BKMR models further demonstrated a positive relationship between the exposure levels of the mixtures and PTB risk, and V was identified as the most important independent variable among the elements. RCS analysis showed an inverted U‐shape effect of V and gestational age, and plasma V more than 2.18 μg/L was considered a risk factor for shortened gestation length. Exposure to metallic elements mixtures consisting of V, As, cobalt, Ni, chromium and manganese in the first trimester was associated with an increased risk of PTB, and V was considered the most important factor in the mixtures in promoting the incidence of PTB. Key messages: The positive joint effect of a metal mixture consisting of vanadium (V), arsenic, cobalt, chromium and manganese on preterm birth (PTB) was observed by applying different interdisciplinary statistical methods.V was defined as the most important risk factor for PTB among the metal mixture.Maternal plasma concentration of V of more than 2.18 μg/L was considered a risk factor for shortened gestation length. [ABSTRACT FROM AUTHOR]

The concentrations of Sr, Tl, and V in soils and plant organs were evaluated at a copper mining site. These are heavy metals that are extremely dangerous and harmful to human and environmental health and, therefore, are on the ATSDR substance priority list. Within the scope of the study, soil samples were taken from different soil depths in the spoil area, the rehabilitation area where planting was performed and adult trees that were at least 20 years old, and the forest area. Soil samples were taken from the rehabilitation and forest areas where Pinus nigra Arnold., Pinus sylvestris L., and Robinia pseudoacacia L. species grow, and leaf, bark, wood, and root samples were taken from trees in the same areas. The study evaluated variations in heavy metal concentrations in soils based on species and soil depth and in plants based on plant species and organs. The study found that the heavy metal concentrations in soils and plant organs generally varied depending on plant species, while these variations were insignificant depending on soil depth. The highest concentrations by species were generally obtained for Sr in Robinia pseudoacacia and for Tl and V in Pinus nigra. [ABSTRACT FROM AUTHOR]

In this study, it is aimed to assess the feasibility of converting vanadium pentoxide into vanadium metal via hydrogen reduction. To achieve this, V2O5 powder is pressed into a cylindrical shape and subjected to a reduction in a high‐temperature microscope under a constant hydrogen flow rate of 0.5 L min−1, within a temperature range of 600–1400 °C. The experimental results are complemented by thermodynamic calculations using FactSage 7.2. The microstructure and composition of the samples are analyzed using scanning electron microscopy with energy‐dispersive X‐ray spectroscopy and X‐ray diffraction analyses. Subsequent to the experiment, only V2O3 and VO are identified in the samples, and no metallic vanadium is observed. [ABSTRACT FROM AUTHOR]

The current study aims to take a step forward in understanding the morphological changes of Fe-rich intermetallics using Fe correctors. Specifically, minor additions of molybdenum (Mo) and vanadium (V) were employed to investigate the morphological changes in hard β-phases (β-Al5FeSi) into granular α-phases in Al–Si–2.5Fe scrap alloy. The microstructure and composition of the intermetallic phases were characterized using SEM-EDS, Xrd, and optical microscopy. The combined effect of vanadium and molybdenum showed significant improvement in intermetallic formation while suppressing the platelet β-Al5FeSi morphologies. Interestingly, a new quinary AlSiFeMoV phase was discovered through SEM-EDS and XRD. Thermal analysis was performed to investigate the influence of Fe-rich intermetallics in the presence of alloying additions V and Mo. Moreover, the microstructure revealed various α-phase morphologies, including quadrilateral, polygonal, and Chinese script structures, which were subjected to detailed intermetallic analysis in this study. A hardness test was performed to understand the effect of Mo and V additions on the Al–Si–2.5Fe scrap alloy. A synergistic effect was observed at 1 wt.% of Mo and V additions in the scrap alloy revealed that significant drop up to 17.19% hardness was observed in the synergistic-affected alloy. [ABSTRACT FROM AUTHOR]

A series of hollow VOx/SiO2 nanofiber catalysts (nV/S-f) with vanadium content ranging from 0.25 wt% to 4.0 wt% were prepared by electrospinning-calcination, and characterized by ICP-MS, XRD, N2 adsorption–desorption, SEM, XPS, UV–Vis-DRS and H2-TPR. Subsequently, the performance of these catalysts in the oxidative dehydrogenation of propane (ODHP) was evaluated. It was found that vanadium species with high dispersivity were obtained when the V content was less than 1.5 wt%. By comparison, 1.0V/S-f catalyst had the best catalytic performance, especially in terms of the propylene selectivity at high-temperature: ~ 77% at 550 °C and ~ 74% at 575 °C. In contrast to the conventional impregnation technique, the catalyst with one-dimensional nanostructure has more catalytic advantages. [ABSTRACT FROM AUTHOR]

The possibility of obtaining a combined titanium-steel construction by directed energy deposition using vanadium or vanadium/nickel interlayers has been investigated. Vanadium wire VnPr-1, nickel wire NP1 grade, and welding wires Sv-08G2S, 316L, and MSG NiFe-1 grades were used for deposition on the end of the titanium plate VT1-0. The use of vanadium as an interlayer deposited on titanium makes it possible to provide a joining with a stable structure, steady hardness distribution, and acceptable manufacturability. The content of dissolved titanium in the vanadium layer has a negative effect on the subsequent deposition of steel, nickel, or iron-nickel alloy. Therefore, the titanium content was reduced to a level of less than 0.5% by the deposition of at least 4 vanadium beads. The results of tensile tests demonstrated that all specimens failed in the elastic section mostly along the interlayers between vanadium and subsequent layers of low-carbon steel, nickel, and iron-nickel alloys deposited on it. The greatest ultimate tensile strength is achieved in the specimen, which is a compound of titanium and steel through interlayers of vanadium and iron-nickel alloy, and constitutes 251 MPa. The only specimen was destroyed along the titanium-vanadium interlayer probably due to brittle ω–phase formation. [ABSTRACT FROM AUTHOR]

Vanadium is a typical low-activation metal and has the advantages of lower neutron irradiation activation, better mechanical properties at high temperature, and higher compatibility with the liquid lithium blanket. However, the effect of helium on the formation of irradiation defects in vanadium has not been adequately explored at low temperatures (below 723 K). Helium ion irradiations of 18 keV up to 0.54 displacement per atom were employed to study the temperature-dependent behavior of irradiation defects in vanadium at 523, 623, and 723 K. Helium bubbles were observed in vanadium under irradiations at all temperatures, but no dislocation loops were observed. With the increase of irradiation temperature, the average size of helium bubbles and swelling increased, and the density of helium bubbles decreased. It is noteworthy that the average size of helium bubbles and swelling increased significantly when the irradiation temperature increased from 623 to 723 K. In addition, pentagonal helium bubbles, helium bubbles nucleated at the grain boundary, and combinations between helium bubbles were observed. [ABSTRACT FROM AUTHOR]

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In view of the recovery and utilization of vanadium from vanadium extraction tailings, the alkaline pressure leaching technology was proposed to realize the leaching and extraction of vanadium from vanadium extraction tailings. The raw material was analyzed and the effects of temperature, sodium hydroxide concentration, reaction time, liquid-solid ratio and stirring speed on the leaching rate of vanadium, chromium and silicon in the tailings were investigated. The results indicate that the leaching rate of vanadium can be controlled at 50% when the temperature is 120 °C, the dosage of sodium hydroxide is 10%, the liquid-solid ratio is 4-6 mL/g, the time is one hour, and the stirring speed is 400 r/min. At the same time, the leaching of chromium and silicon is reduced as much as possible. The purification degree of the solution is maintained, and good solution conditions are provided for the subsequent extraction of vanadium. [ABSTRACT FROM AUTHOR]

Fe-containing intermetallic compounds (IMCs) are among the most detrimental second phases in aluminum alloys. One particularly harmful type is θ-Al13Fe4, which exhibits a needle- or plate-like morphology, leading to greater degradation of mechanical properties compared to other Fe-IMCs with more compact structures, such as α-Al15(Fe,Mn)3Si2. The addition of alloying elements is a crucial strategy for modifying the microstructure during the solidification process of aluminum alloys. This study investigates the effects of adding vanadium (V) and zirconium (Zr) on the morphology and crystal chemistry of θ-Al13Fe4 in an Al-4Fe alloy, employing a combination of experimental observations, first-principle calculations, and thermodynamic analysis. Our findings indicate that zirconium significantly refines both the primary θ-Al13Fe4 particles and the α-Al grains. Additionally, a small amount of vanadium can be incorporated into one of the Wyckoff 4i Al sites in θ-Al13Fe4, rather than occupying any Fe sites, under casting conditions, in addition to the formation of binary Al-V phases. [ABSTRACT FROM AUTHOR]

An oxalate complex of vanadyl(IV) (Bu4N)2[VO(C2O4)2] (I) was synthesized and used as a vanadium precursor. The synthesis and characterization of the double complex salts [Pt(NH3)4][VO(H2O)(C2O4)2]·2H2O (III) and {[Pt(NH3)4][VO(C2O4)2]}n (IV) were carried out. The complexes obtained were characterized by IR and diffuse reflectance spectroscopy, single-crystal and powder X-ray diffraction, and EPR. The magnetic properties of I, III, and IV were also studied. The process of thermal decomposition of the synthesized complexes in reducing and inert atmospheres was studied, and the composition of the released gases was determined. Thermal decomposition of the salts in a hydrogen atmosphere at 600 °C resulted in the formation of a bimetallic solid solution, Pt0.6V0.4. [ABSTRACT FROM AUTHOR]

We demonstrated a nonenzymatic electrochemical sensor based upon vanadium-doped nickel oxide composite with graphitic carbon nitride. The g-C 3 N 4 was prepared by annealing Urea at 550 °C for 3 h in a muffle furnace. The nanocomposite was synthesized using a microwave-assisted method, followed by thermal annealing at different temperatures. The successful formation of V–NiO/g-C 3 N 4 was confirmed by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy. SEM images show the layered sheets with porous structure, which depends on annealing temperature; as we increase the temperature, the porosity increases. Afterwards, the electrochemical sensing properties were verified by CV, LSV, DPV, and amperometric studies in 0.2 M KOH in the presence of Ascorbic acid and Dopamine. The experimental results show that our prepared sample has excellent electrochemical biosensing abilities towards AA and DA with LOD 1.16 μM and 0.16 μM, respectively. It also offers good selectivity, exceptional reproducibility, and long-term stability owing to the combined effect of NiO and g-C 3 N 4. Finally, the electrochemical sensing of H 2 O 2 was detected in the same environment by conducting CV and amperometric studies. Our modified electrode has proven its noble ability to sense H 2 O 2 with excellent repeatability, stability and low LOD 0.2 μM with a wide linear working range (0.5 mM–4 mM). It has the potential to be used for multi-molecule selection biosensing with excellent selectivity and sensitivity. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Interlayer intercalation engineering shows great feasibility to improve the structure stability of the layered oxides. Although high Zn-storage capability has been attained based on the pillar effect of multifarious intercalants, an in-depth understanding the synergistic effect of intercalated multiple metal ions is still in deficiency. Herein, alkali metal ion K+, alkaline earth metal ion Mg2+ and trivalent metal ion Al3+ are introduced into the VO interlayer of V 2 O 5. Due to the different electronegativity and hydrated ion radius of K+, Mg2+ and Al3+, adjusting the relative proportions of these metal ions can achieve an appropriate interlayer spacing, stable layer structure and regular morphology, which facilitates the transport kinetics of Zn2+. Under the synergistic effect of pre-intercalated multi-metal ion, the optimal tri-metal ion intercalated hydrated V 2 O 5 cathode exhibits a high specific capacity of 382.4 mAh g−1 at 0.5 A g−1, and long-term cycling stability with capacity retention of 86 % after 2000 cycles at the high current density of 10 A g−1. Ex-situ and kinetic characterizations reveal the fast charge transfer and reversible Zn2+ intercalation mechanism. The multi-ion engineering strategy provides an effective way to design desirable layered cathode materials for aqueous zinc-ion batteries. [ABSTRACT FROM AUTHOR]

Based on the strong binding properties of hydroxylamino-1,3,5-triazine (BHT) for hard metal ions, a novel spectroscopically labelled triazine-hydroxylaminato ligand, N,N′-(6-(9H-carbazol-9-yl)-1,3,5-triazine-2,4-diyl)bis(N-methylhydroxylamine) (H2cbht), was synthesized. Reaction of H2cbht with FeIII, VV and UVI resulted in the synthesis of [UVIO2(cbht)(DMF)(MeOH)], 1, (PPh4)2([UVIO2(Hcbht)2]·2[UVIO2(Hcbht)(cbht)]), 2, (PPh4)2[(UVIO2)3(μ-cbht)2(cbht)2], 3, Na[VVO2(cbht)], 4, and (PPh4)[FeIII(cbht)2], 5. The complexes were characterized by X-ray crystallography showing strong chelation of the metal ions with the BHT chelating moiety H2cbht. The DMSO/DMF solutions of the complexes were characterized by NMR, UV-vis and electrochemistry, confirming the high affinity of H2cbht for FeIII, VV or UVI. The luminescence properties of the carbazole group were retained in the BHT adduct of the H2cbht ligand. Interaction of the metal ions with H2cbht resulted in quenching of the luminescence of H2cbht. Stern–Volmer plots of luminescence vs. concentration of the metal ions are linear and suitable for the determination of the concentration of metal ions in nM range concentrations. Benesi–Hildebrand plots show that the metal-to-ligand ratio is 1 : 1 while the formation of the metal complexes exhibits high association constants. [ABSTRACT FROM AUTHOR]

[V(N-2,6-Cl2C6H3)(CHSiMe3)(OC6X5)(NHC)] [X = F (1), Cl (2), NHC = 1,3-bis-(2,6-dimethylphenyl)-imidazol-2-ylidene], exhibited remarkable catalytic activities [TOF = 133–193 s−1 (1), 90.9–126 s−1 (2)] for ring opening metathesis polymerisation (ROMP) of norbornene (NBE) at 25 °C to afford ring-opened polymers not only with high cis-(93–98%) selectivity, but also with exclusive syndiotactic stereo-regularity. These polymerisations proceeded in a living manner under optimised conditions. The activity improved at 50 °C with decreasing in the cis specificity. Synthesis and the structural analysis of the fluorinated alkoxide complexes, [V(N-2,6-X2C6H3)(CHSiMe3){OC(CF3)3}(NHC)] [X = F (3), Cl (4)] have been studied, and the difluorophenylimdo complex (3) exhibited comparable catalytic activities for ROMP of NBE. The cis selectivities in the resultant polymers prepared by 3 were low (88%) and the selectivities in the ring-opened poly(tetracyclododecene) (TCD) were low (61–66%) compared to those in poly(NBE)s. The resultant ring opened poly(TCD) possessed syndiotactic stereo-regularity confirmed by DSC thermogram of the hydrogenated polymers. [ABSTRACT FROM AUTHOR]