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Magnesium vanadates (MgV 2 O 6 , Mg 2 V 2 O 7 and Mg 3 V 2 O 8) are common redox catalysts for organic reactions and excellent energy storage materials. However, due to the diversity of magnesium vanadates and their interconvertibility, it is difficult to accurately synthesize a species of magnesium vanadate or control its stability during functioning. Herein, the reaction kinetics of MgO-V 2 O 5 system was studied for controllable synthesis of magnesium vanadates. The MgO-V 2 O 5 diffusion couples were prepared to explore the interface reaction characteristics of the MgO-V 2 O 5 system at different reaction time. During reaction, the thickness of the diffusion layer and diffusion coefficient gradually increased and reached a maximal value of 29.55 μm and 6.06 × 10−11 cm2 s−1 at 10 h, which diffusion is faster than that of CaO-V 2 O 5 system. Additionally, the interconvertible mechanisms of different magnesium vanadates were investigated using XRD and SEM/EDS techniques. MgV 2 O 6 was produced during the synthesis of Mg 2 V 2 O 7 in the initial 4 h, which converted into Mg 2 V 2 O 7 at a longer synthesis time. Mg 2 V 2 O 7 was found during the generation process of Mg 3 V 2 O 8 ; with abundant MgO, Mg 2 V 2 O 7 converted into Mg 3 V 2 O 8. These findings provide important insights into the accurate control of magnesium vanadate synthesis and even the vanadium extraction process. [ABSTRACT FROM AUTHOR]

Magnesium–sodium hybrid ion batteries (MSHIBs) are expected to achieve excellent rate capability. However, existing MSHIB cathodes exhibit low ionic conductivity and poor structural stability, resulting in low power density and cycle lifespan. Herein, sodium‐rich Na3.7V6O16·2.9H2O (Na‐rich NVO) nanobelts are synthesized as MSHIB cathodes. Excess Na+ induced NaO5 and NaO3 interlayer pins, which ensures NVO structural stability to accommodate Mg2+ and Na+. They also confine the migration pathway of cations to the diffusion direction, lowering the migration barriers of Mg2+ and enhancing the ionic conductivity. Excess interlayer Na+ increases the electronic conductivity of the involved Na‐rich NVO cathode. The cathode exhibits a high Mg2+ diffusion coefficient, and the resulting MSHIBs exhibit a power density of 3.4 kW kg−1 and a lifespan of 20 000 cycles at 5.0 A g−1, with a capacity retention rate of 85%. Overall, this study paves the way for designing and developing fast‐charging secondary batteries. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur (Li−S) batteries display promise as redox‐based batteries, where separators are an essential part of preventing short‐circuiting of the positive and negative electrodes, while the shuttle effect is a critical issue of separators. Currently, commercial PP separators are weak in inhibiting the polysulfides shuttling, so modified separators are needed to inhibit it to improve the battery performance. This paper reports that CeVO4/KB composites act as separator materials. CeVO4/KB modified PP separators enhanced the adsorption of LiPSs, accelerated the rate of Li+ migration, and catalyzed the conversion of LiPSs. These bring about the effect that CeVO4/KB/PP batteries reach 1200.9 mAh g−1 in the first cycle with a capacity retention rate of 86.5 % after 100 cycles at 0.2 C and reach 882.7 mAh g−1 of the initial cycle with a capacity decay rate of 0.063 % after 1000 cycles at 3 C. This work introduces rare earth metal vanadates to modify the separator, adding new ideas for designing separators for good‐performance batteries. [ABSTRACT FROM AUTHOR]

Rare earth vanadates are promising for solar‐to‐fuel conversions, yet their photocatalytic efficiency is limited by the substantial recombination of photo‐generated carriers. Constructing heterojunctions is recognized as an effective approach to improving charge carrier separation in vanadates. Nonetheless, inefficient charge transfer often results from the poor quality of interfaces and non‐directional charge transfer within these heterojunctions. Herein, an S‐scheme AgInS2/CeVO4@Biocharx (AIS/CV@Cx) heterojunction photocatalyst is designed and synthesized through a straightforward freeze‐drying and calcination three‐step process, aimed at photocatalytic co‐production of xylonic acid and carbon monoxide (CO) from xylose. The AIS/CV@C2 heterojunction achieves an optimal yield of 67.74% for xylonic acid and a CO release of 29.76 µmol from xylose. The enhanced photocatalytic performance of the AIS/CV@C2 heterojunction is attributed to three key factors: I) the high‐quality interface and intimate contact within the AIS/CV@C2 heterojunction significantly reduce undesirable carriers recombination, II) the staggered band structures and directed carriers transfer in the AIS/CV@C2 heterojunction notably improve spatial carriers separation/migration, and III) the incorporation of biochar boosts the conductivity of the AIS/CV@C2 heterojunction. This work presents a straightforward yet effective method for fabricating vanadate heterojunctions, highlighting the importance of quality interfacial contact and directed charge transfer in amplifying photocatalytic performance. [ABSTRACT FROM AUTHOR]

A Ce-Cu 2+1 O/Cu 3 VO 4 -CF catalyst was successfully fabricated for efficient electrocatalytic nitrate reduction to ammonia, which demonstrates remarkable performance under alkaline conditions, achieving an NH 3 Faradaic efficiency (FE) of 93.7% at −0.5 V (vs. RHE), with an NH 3 production rate of 18.905 mg/h cm−2. [Display omitted] • A Ce doped Cu 2+1 O/Cu 3 VO 4 -CF electrocatalyst is first reported. • Ce-Cu 2+1 O/Cu 3 VO 4 -CF shows superior electrocatalytic NO 3 RR performance. • Ce-doping adjusts the density of states of the catalyst and creates more O v , which promotes the NO 3 RR activity. • DFT calculations further reveal the changes the d-band center and the rate-degerming step. The electrocatalytic nitrate reduction to ammonia reaction (ENO 3 RR) holds great potential as a cost-effective method for synthesizing ammonia. This work designed a cerium (Ce) doped Cu 2+1 O/Cu 3 VO 4 catalyst. The coupling of vanadium-based oxides with Cu 2+1 O effectively adjusts the catalyst's electronic structure, addressing the inherent issues of limited activity and low conductivity in typical copper-based oxides; moreover, Ce doping generates oxygen vacancies (O v), providing more active sites and thereby enhancing the ENO 3 RR performance. The catalyst exhibits superior NH 3 Faradaic efficiency (93.7 %) with a NH 3 yield of 18.905 mg h−1 cm−2 at −0.5 V vs. RHE under alkaline conditions. This study provides guidance for the design of highly efficient catalysts for ENO 3 RR. [ABSTRACT FROM AUTHOR]

The interaction of decavanadate with the cationic organic dyes methylene blue (MB), toluidine blue (TB) and rhodamine B (RB) was explored. For that purpose, a novel decavanadate salt (2,3-ampH)6[V10O28]·4H2O (2,3-ampV10), where 2,3-ampH+ = 2-amino-3-methylpyridinium, and two salts with the organic dyes (MB)4[H2V10O28]·10.8H2O (MBV10) and (TB)4(H2V10O28)·10H2O (TBV10) were synthesized. The compounds were characterized by elemental analysis, powder X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy and infrared spectroscopy. The salts 2,3-ampV10 and MBV10 were also characterized by single-crystal X-ray diffraction, while TBV10 was isolated as an amorphous solid. The supramolecular features of MBV10 showed columns of MB cations connected to V10 through H-bond interactions that resulted in channels filled with water molecules. The absorption spectrum of MBV10 was studied by density functional theory (DFT) calculations at the X3LYP/def2-TZVP level using the crystallographic data. The efficacy of 2,3-ampV10 to bleach MB solutions at pH 6.2–6.5 was outstanding, achieving nearly 90% discoloration in only 5 min, presenting moderate efficacy towards TB and quite negligible towards RB. Moreover, a metachromatic effect was observed in the TB solution at pH 3. The IR spectra of the isolated solids and the mass spectra of the supernatants suggest both adsorption and cation exchange as the main responsible processes for the bleaching of MB and TB solutions. The present work has tackled many fronts related to the chemistry of POVs, mainly synthetic, structural, and environmental approaches. [ABSTRACT FROM AUTHOR]

A set of 23 vesbine-bearing samples from Vesuvius volcano (Italy), preserved in the collection of the Royal Mineralogical Museum of Naples, University Federico II (RMMN), have been investigated to identify the mineral assemblages and their mode of formation. In the late 19th century, fumarole-related yellow patinas coating some historical lavas from Vesuvius were believed by Scacchi to contain a new element, vesbium, similar to vanadium in a mineral he called vesbine. Subsequent studies rejected vesbium and showed that vesbine was a poorly defined mixture of copper vanadates and halides. The vesbine samples studied here consist of yellowish to yellow-green-blue encrustations on Vesuvius lavas and have been analyzed by combined optical microscopy, SEM-EDS, XRPD, FTIR, and TEM-HRTEM-EDS. Results reveal complex mineral associations, including vanadates, halides, carbonates, oxides, silicates, tungstates/molybdates, and sulfates. The vanadates correspond to mottramite, volborthite, and vanadinite; subordinate amounts of descloizite were detected by XRPD and FTIR investigations. Several additional non-essential elements have been detected in the vanadates, including Mn, Zn, and As. The occurrence of wulfenite- and stolzite-rich phases indicates the presence of Mo and W, along with Pb, in the mineralizing fluids. Mn-rich phases, commonly in mixtures with silicates and vanadates, were also observed. These minerals are formed by a combination of different processes, including rock-fluid interactions, gas-water interactions, and alteration/oxidation of primary fumarolic minerals. Temperatures for the depositions of the vanadates-bearing assemblages are interpreted to be in the range of 100 to 400 °C. [ABSTRACT FROM AUTHOR]

This work provides new insights into the nature of the polaronic transport in xV2O5–(100−x)P2O5, 41 ≤ x ≤ 89 mol% glasses from analysis of their conductivity over a wide range of frequencies and temperatures, and correlation of the electrical parameters to the structural models of these materials. The results show that the linear increase in direct current (DC) conductivity with the increase in V2O5 could be related to the formation of a vanadate subnetwork, which is characterized by a length distribution of V–O bonds and variations in linkages between different vanadate units. Such a structurally complex network offers multiple conduction pathways which are favorable for polaron hopping. The Summerfield scaling of conductivity spectra reveals a temperature‐invariant mechanism of polaron transport for all glasses and the same local structural environment of polarons at higher V2O5 contents due to the same ratio of vanadate units present in the network. Also, this study highlights the similarities and differences in the nature of the polaronic transport of vanadate–phosphate glasses and other polaronically conducting phosphate glasses containing WO3, MoO3, and Fe2O3, and pins down a pivotal role of the glass structure in electrical processes in these materials. [ABSTRACT FROM AUTHOR]

Silver vanadate (Ag 3 VO 4) is considered one of the most important semiconductors. It finds practical applications in electrochemical cells, as bactericidal and virucidal agents, in photocatalysis, and environmental remediation. Despite the impressive experimental progress, the dependence of the properties of a material is strongly linked to its chemical composition and structure. In this sense, the peculiar physical-chemical properties of the vanadate's class have become important. However, the fundamentals of structure in this material remain poorly understood, and the theoretical insight into the morphology linked to its properties is completely missing. In the present study, different synthesis times were tested in the obtention of Ag 3 VO 4 crystals by the microwave-assisted hydrothermal method, and their properties were discussed based on experimental results and quantum mechanics simulations. Structural characterizations (XRD, Raman and UV–vis spectroscopy, FE-SEM, and TEM analyses) confirmed the material order at short, medium, and long-range. Theoretical calculations contributed to identifying the atom distribution in the structure, nature of the type of electronic transition, and density of states present in the valence and conduction bands. The topological analysis of the electron density indicated transit chemical interactions and unexpected argentophilic interactions, and Mulliken, Hirshfeld and Bader population analysis provided the charges present on the chemical elements of the crystal. Predicted theoretical surface shapes and their stabilities were evaluated along with FE-SEM images. [ABSTRACT FROM AUTHOR]

Combustion process was used to synthesize the dysprosium (Dy3+)-doped sodium calcium vanadate (NaCaVO4) phosphor. The structural, optical and morphological investigations were carried out with the dopant concentrations ranging from x = 0–3 mol% for which X-ray diffraction, photoluminescence spectroscopy, SEM and UV–Vis spectroscopy were used. We have explored that the XRD results indicate vibrant, clear and well-defined peaks that are matched to the NaCaVO4 standard card confirming that the phosphor powder crystallized in the orthorhombic phase with space group Cmcm. From the FESEM pictures, the particles had an agglomerated morphology with irregular shapes and sizes in the nm range. The PL properties of undoped and Dy3+-doped NaCaVO4 were investigated using a 310 nm excitation source to determine the suitability for use in displays. The emission spectrum exhibited two sharp peaks at 450–500 and 550–600 nm and a weak peak at 650–700 nm, which is assigned to Dy3+-emission transitions of 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H11/2 (red). Doping of NaCaVO4 with Dy3+ for x = 0.25–3 mol% concentrations resulted in band gap modifications in the range of 3.341–3.866 eV. The material that we have taken up might be investigated as a new phosphor that could be activated by UV light-emitting diode (LED) light for solid-state lighting and display applications. [ABSTRACT FROM AUTHOR]

The fast advancements in technology have generated significant interest in optoelectronic materials. Nevertheless, the difficulty of creating affordable materials with exceptional optical characteristics is an ongoing challenge. Therefore, the objective of this work was to tune the optical properties of poly(methyl methacrylate) (PMMA) by embedding silver vanadate (SV) in the polymer matrix. Moreover, the wettability test of the fabricated composite membranes showed a hydrophobic behavior, with the PMMA film containing 0.6 wt.% SV showed a contact angle of 86.75 ± 0.7°. Furthermore, SV showed high thermal stability with a maximum weight loss of 0.74% at 830°C, which is very high thermal stability at high temperatures. In addition, the 0.6 wt.% SV@PMMA film exhibited a maximum weight loss of 96.7% at 785°C. Moreover, the 0.6 wt.% SV@PMMA film showed the lowest indirect band gap energy (2.02 eV) compared to the other films and pure SV NPs. The findings demonstrate the potential of the synthesized films for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Three decavanadate (V10O28)6- containing compounds were used to test their catalytic activity in the sulfoxidation reaction of diphenyl sulfide using environmentally friendly conditions (low temperature, non-toxic solvent). The compounds of interest for our study, (NH4)2(H2en)2{V10O28}·4H2O, (H2en)3{V10O28}·6H2O and {Li2(H2O)10}(V10O28)(NH4)4, were evaluated, showing good activity in sulfoxidation reaction and leading to complete conversion of the sulfide even after three runs. The tetraammonium decaaqualithium decavanadate, with the formula {Li2(H2O)10}(V10O28)(NH4)4 was obtained through a modified literature method and its structure re-determined and investigated, giving similar results as previously described and confirming the structure of the used material. [ABSTRACT FROM AUTHOR]

A series of non-innocent halogen substituted Schiff base vanadium catecholates were added with different electron donating and withdrawing substituents on the catecholates to investigate the electronic effects on the properties of this class of compounds. We hypothesized that the electronic changes would be reflected in their redox properties and stabilities, which should lead to differences in their biological properties. Using UV-spectroscopy, we measured their hydrolytic stability, and using electrochemistry, we characterized their redox properties. Adding one substituent on the catecholate group on the complexes changed the redox potentials of the complexes; however, less impact on the hydrolytic stability was observed. We discovered that hydrolytic stability was crucial to the anti-proliferative effects on glioblastoma cells, and most of these compounds had effects similar to vanadates regardless of their different redox properties. Hence, we could not determine the importance of changing the electronic properties and redox potential on the anti-proliferative effects of mono-substituted catecholates. However, the studies did show that the pKa of the substituted catecholate showed a linear correlation with the redox potential of the non-innocent Schiff base vanadium complexes, which will be important in future investigations into this class of complexes. [ABSTRACT FROM AUTHOR]

This study presents a vanadate-exchanged Zn-Al layered double hydroxide (LDH) coating on a ZX21 Mg alloy (Mg-2.15 wt%Zn-0.97 wt%Ca) by electrodeposition and immersion anion-exchange post-treatment. With the prepared vanadate-exchanged electrodeposited Zn-Al LDH coating, the corrosion resistance of the ZX21 Mg alloy improves with a decrease in the corrosion current density from 62.4 μA/cm2 to 3.32 μA/cm2. The fabricated vanadate-exchanged electrodeposited Zn-Al LDH coating contains complex anions in the interlayers, including mainly nitrate (NO3−), carbonate (CO32−), and different vanadates. The coating not only serves as a physical barrier on the ZX21 Mg alloy but also absorbs chloride ions in the environment through anion exchange and inhibits corrosion with the reduction of the interlayer vanadates. Furthermore, the vanadates can also be released into the damaged area of the coating. [ABSTRACT FROM AUTHOR]

Central nervous diseases caused by noradrenaline (NA) have attained special attention. NA is involved in many different physiological functions that occur throughout the central nervous system, including modifying sensory input, attention regulation, arousal, and sleep regulation. Hence, rapid, precise, and trustworthy NA detection is crucial. Here we have created Nd(VO4)/GA nanocomposite for the sensitive and selective detection of noradrenaline. Successful fabrication of Nd(VO4)/GA nanocomposite was verified by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) techniques. Optical properties were evaluated by colorimetric and fluorometric detection using UV–Vis absorption and photoluminescence spectroscopy. The created sensor has demonstrated superior noradrenaline detection capabilities using fluorometry with an LOD of 48.48 nM in a wide linear range of 6–215 nM, and for colorimetry, the LOD and linear range were 33.89 nM and 10–80 nM. Furthermore, the manufactured sensor has demonstrated exceptional reproducibility, strong stability, anti-interference capabilities, and excellent repeatability for noradrenaline detection. [ABSTRACT FROM AUTHOR]

Yttrium orthovanadate (YVO 4), a wide-bandgap photocatalyst was tuned into a visible responsive material by anchoring an organic framework on the surface of YVO 4 nanoparticles using polyethyleneimine (PEI). The surface organic framework was identified as the decomposed PEI derivatives with the carbonyl and carboxylic acid functional groups by the FTIR and XPS analyses. The top of the valence band (VB) was raised and the bottom of the conduction band was moved down; hence, the band gap of YVO 4 was reduced to absorb the light in the visible region for all three synthesized samples, which was confirmed by DRS UV–Vis analysis. The functional groups facilitated more water molecules on the YVO 4 surface via hydrogen bonding; hence, the YVO 4 surface acquired superhydrophilicity. Among the three YI, YII, and YIII samples synthesized with three different calcination temperatures of 80, 260 and 400 °C respectively, YII showed many advantageous photocatalytic properties. The optimum loading of organic compounds obtained on YII surface at 260 °C, which improved the surface area, visible light absorption, hydrophilicity, and exciton's life. Hence, YII showed a better performance of 3.75 mmol h−1g−1 cat H 2 production than YI and YII. This work interestingly revealed the influence of calcination temperature on surface functionalization and the performance of catalytic materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Topological constraint theory has emerged as a rapid, predictive method to quantify the relationship between structural rigidity and glass properties. Understanding the structure of telluro‐vanadate (TeO2–V2O5) glasses has remained difficult owing to their complex mixture of structural units. Here, we propose a topological model that accurately captures the glass structure and can be used to predict properties such as glass transition temperature and hardness. The experimentally obtained properties are in agreement with predicted properties by the model suggesting that this simplified structural model accurately describes the V2O5–TeO2 structure. [ABSTRACT FROM AUTHOR]

The bismuth vanadate (BiVO4) photoanode receives extensive attention in photoelectrochemical (PEC) water splitting. However, the high charge recombination rate, low electronic conductivity, and sluggish electrode kinetics have inhibited the PEC performance. Increasing the reaction temperature for water oxidation is an effective way to enhance the carrier kinetics of BiVO4. Herein, a polypyrrole (PPy) layer was coated on the BiVO4 film. The PPy layer could harvest the near-infrared light to elevate the temperature of the BiVO4 photoelectrode and further improve charge separation and injection efficiencies. In addition, the conductive polymer PPy layer acted as an effective charge transfer channel to facilitate photogenerated holes moving from BiVO4 to the electrode/electrolyte interface. Therefore, PPy modification led to a significantly improved water oxidation property. After loading the cobalt–phosphate co-catalyst, the photocurrent density reached 3.64 mA cm−2 at 1.23 V vs the reversible hydrogen electrode, corresponding to an incident photon-to-current conversion efficiency of 63% at 430 nm. This work provided an effective strategy for designing a photothermal material assisted photoelectrode for efficient water splitting. [ABSTRACT FROM AUTHOR]

We have switched polarization in calcium orthovanadate single crystal with as-grown domain structure consisting of isolated domains with charged domain walls (CDWs) located in the bulk using pretreatment by ac field and subsequent switching in dc field at the elevated temperature. The formation of the domain ledges at the CDW in the bulk and their growth in the polar direction has been revealed. The isolated domains with optically well-defined walls appeared when the ledge tops reached the surface, their shape and sizes remaining constant during further switching. Unlike usual continuous domain wall motion, we have observed the discrete switching by arising of the isolated domains without any input of the traditional domain nucleation at the polar surface. The obtained results have been explained under the assumption that at the used experimental conditions, the applied field is above the threshold value for ledge nucleation at CDW in the bulk, but below the threshold for domain wall motion at the surface. Thus, we have obtained the discrete switching by ledge growth without any sideways motion of the domain walls and domain coalescence. The nonuniform evolution of the domain structure at the surface is due to the dependence of the switching rate on the distance from CDW to the polar surface, which is random in the studied domain structure. [ABSTRACT FROM AUTHOR]

The prepared NVOY electrode achieves high stability and excellent cycle performance for AZIBs by embedding polypyrrole in ammonium vanadate layers to remove excess ammonium ions, expand the interlayer spacing, and enhance electronic conductivity. [Display omitted] Ammonium vanadate with stable bi-layered structure and superior mass-specific capacity have emerged as competitive cathode materials for aqueous rechargeable zinc-ion batteries (AZIBs). Nevertheless, fragile N H...O bonds and too strong electrostatic interaction by virtue of excessive NH 4 + will lead to sluggish Zn2+ ion mobility, further largely affects the electro-chemical performance of ammonium vanadate in AZIBs. The present work incorporates polypyrrole (PPy) to partially replace NH 4 + in NH 4 V 4 O 10 (NVO), resulting in the significantly enlarged interlayers (from 10.1 to 11.9 Å), remarkable electronic conductivity, increased oxygen vacancies and reinforced layered structure. The partial removal of NH 4 + will alleviate the irreversible deammoniation to protect the laminate structures from collapse during ion insertion/extraction. The expanded interlayer spacing and the increased oxygen vacancies by the virtue of the introduction of polypyrrole improve the ionic diffusion, enabling exceptional rate performance of NH 4 V 4 O 10. As expected, the resulting polypyrrole intercalated ammonium vanadate (NVOY) presents a superior discharge capacity of 431.9 mAh g−1 at 0.5 A g−1 and remarkable cycling stability of 219.1 mAh g−1 at 20 A g−1 with 78 % capacity retention after 1500 cycles. The in-situ electrochemical impedance spectroscopy (EIS), in-situ X-ray diffraction (XRD), ex-situ X-ray photoelectron spectroscopy (XPS) and ex-situ high resolution transmission electron microscopy (HR-TEM) analysis investigate a highly reversible intercalation Zn-storage mechanism, and the enhanced the redox kinetics are related to the combined effect of interlayer regulation, high electronic conductivity and oxygen defect engineering by partial substitution NH 4 + of PPy incorporation. [ABSTRACT FROM AUTHOR]

Among all the cathode materials in lithium-ion batteries (LIBs), V 2 O 5 has gained a lot of attention due to its high theoretical specific capacity (∼440 mAh g−1). However, only some of the lithium-ions can be reversibly extracted after inserting into V 2 O 5 cells, making the actual reversible capacity of the crystalline V 2 O 5 cathode material much lower than its theoretical specific capacity. In this work, we prepared Li 2 O–V 2 O 5 –P 2 O 5 ternary glass by melt-quenching method. Subsequently, we grew nano-sized crystals and super-lattice structures in the glass matrix by precise heat treatment. Systematic structural, electrochemical tests and first-principles computations have shown that a reasonable amount of super-lattice structure can significantly enhance the electronic and ionic conductivity of glass matrix materials. Benefiting from this, the LVP-70-2 composite cathode exhibited excellent lithium storage performance with a stable reversible capacity of nearly ∼280 mAh g−1 at 50 mA g−1 and an outstanding cycling performance of a remaining capacity of 90 mAh g−1 at 1600 mA g−1 after 200 cycles. [ABSTRACT FROM AUTHOR]

It is extremely challenging to accomplish second‐harmonic generation (SHG) in the whole mid‐infrared (MIR) region for oxide crystals due to their short IR absorption cutoff wavelengths. Herein, a new MIR nonlinear optical (NLO) crystal of K4ZnV5O15Cl (KZVC) is designed and synthesized by the aliovalent substitution of [VIIIO5] with [ZnIIO4Cl] based on the K2(VO)(V2O7) matrix. KZVC features an ordered 2D [ZnV5O15Cl]∞ layered structure comprising [ZnO4Cl] / [VO5] square pyramids and [VO4] tetrahedron as functional units. Importantly, KZVC shows excellently balanced performances of strong SHG responses (12 × KDP @ 1064 nm, 1.1 × AgGaS2 @ 2.05 µm), broad IR transparency range (0.52‒10 µm), congruent‐melting behavior, and highest laser‐induced damage threshold (LIDT) (60 × AgGaS2 @ 1064 nm) among the reported vanadates. Most remarkably, KZVC represents the first example in the oxide‐based IR NLO crystals that can achieve phase matching in a wide wavelength range extending from 1.8 to 10 µm, fully covering the important MIR atmospheric windows (3‒5 µm). [ABSTRACT FROM AUTHOR]

The development of highly efficient and environment friendly methods for arsenic pollution treatment has attracted special attention. Herein, a new polyoxometalate-thiacalix[4]arene-based metal-organic complex [Ag2L(HL)][PW12O40]·2C2H5OH·2CH3CN (1) (L = thiacalix[4]arene-based ligand) was synthesized and applied for BiVO4 (BVO) surface modification to efficiently enhance the simulated sunlight-driven photoelectrocatalytic oxidation of arsenic(III). Compared with the pristine BVO, the removal efficiency of arsenic(III) was drastically increased to 312% at 0.6 V with the optimized 1@BVO photoanode (B1-20) versus the saturated calomel electrode (SCE) under the simulated sunlight (100 mW cm-2). The removal efficiency of arsenic(III) (25 mg L-1) with B1-20 was up to 100% within 40 min with a faradaic efficiency of 45%. More importantly, electron spin resonance measurements and reactive species trapping experiments demonstrated that the Z-scheme heterojunction formation of 1 plays a key role in the enhanced photoelectrocatalytic performance of 1@BVO. Furthermore, density functional theory (DFT) calculations were used to investigate the relationship between the photoelectrocatalytic properties and the structure of 1. This work developed a new photoelectrocatalytic application for the polyoxometalate-thiacalix[4]arenebased metal-organic complexes by their efficient combination with BVO. [ABSTRACT FROM AUTHOR]

Solution combustion Method for synthesis of alumina nanoparticles in a microwave oven represents a well-established technique for the fabrication of bimetallic metal oxide nanomaterials. In this process, citric acid functions as a pivotal fuel, facilitating the combustion of single-phase oxide materials and enabling the synthesis of multiphase nanomaterials. Utilizing self-propagating combustion methods with citric acid as the fuel source, nanoscale Alumina vanadate (AlV2O7) materials can be successfully synthesized. The synthesis procedure involves the ignition of Aluminum oxide (AlO2) and ammonium meta-vanadate (NH4(VO3)) in an open environment, allowing complete combustion to occur within approximately 15 min in a microwave setting. The precursor concentrations used 13.31 g/50 mL for Aluminum oxide and 0.7291 g/50 mL for ammonium meta-vanadate. Heating parameters included a microwave power of 2.45GHZ 800 watts and a reaction time of 15 minutes. Subsequent research endeavors have focused on investigating the adsorption behavior of lead and mercury ions onto the resultant sample. Due to the impressive adsorption active sites that are present on the sample, this sample exhibits significant adsorption. The produced metal oxide sample behaves well as adsorbents for heavy metal ions, according to an adsorption research., and their potential applications can be use as Catalysis, sensing, Energy Storage, Environmental Remediation. The structural characteristics of the as-prepared AlV2O7 and the adsorbed sample were meticulously examined using powder X-ray diffraction (XRD) analysis. Morphological analysis of the freshly synthesized AlV2O7 and the adsorbed sample material was conducted using scanning electron microscopy (SEM) and Transmission Electronic Microscopy (TEM). FTIR Analysis was also employed to characterize the functional groups present the peak 3800 cm-1 corresponds to the water of absorption's vibration frequency at 1089 cm-1 are assigned to the V=O stretching mode. RAMAN (125.1, 213.6 and 307.2 cm-1 is assigned to AlO2) and The band appeared at 702 cm-1 in the Raman spectrum can be ascribed to stretching vibration of short V=O bond. Furthermore, a comprehensive study was carried out to evaluate the adsorption efficacy of heavy metal ions onto the AlV2O7 sample at ambient temperature (400-600). [ABSTRACT FROM AUTHOR]

The vanadate units have been theoretically investigated through density functional theory calculations. The global reactivity indices have been optimized. The obtained results revealed that the (Q0) [VO4]3-unit shows an electrondonor character, while the units Q1, Q2, and Q3 units are evidenced to exhibit an electron-acceptor feature. The transition from one unit to another is found to be accompanied by an increase in the number of bridging oxygen atoms, in accordance with the highlighted changes in Mulliken charges. Moreover, the analysis of the optimized electrostatic potential surfaces indicated a higher likelihood of nucleophilic attacks on the vanadium atoms. Predictions for infrared and Raman spectra were also conducted, revealing changes in symmetric and asymmetric vibrational bands as the number of bridging oxygen atoms varied. Additionally, Fukui indices were employed to identify the preferred sites for the electrophilic attack within the (Q0) [VO4]3-unit on the Q1, Q2, and Q3 vanadate units. [ABSTRACT FROM AUTHOR]

Silver ions are considered an antibacterial candidate for numerous applications. In this regard, different phases of nanoparticles containing silver were prepared, including silver phosphate and magnesium vanadate, to be incorporated into a polymeric blend based on polyvinyl alcohol (PVA) and hyaluronic acid (HA). These blends were cast in thin films, while different concentrations of the nanoparticles were embedded through the films to promote their adhesion features. In addition, the surface topography of the films was investigated. It was shown that the grain size of silver phosphate was around 84–300 nm, while that of magnesium vanadate was around 43–66 nm. The porosity appeared to be high on the surface. In addition, the surface roughness increased with the addition of nanoparticles. Furthermore, the Mg3(VO4)2@PVA/HA film has the most efficient antibacterial action; the inhibition zone around E. coli species was 19.5 ± 0.5 mm, while that around S. aureus was 16.0 ± 1.0 mm. Additionally, the Ag3PO4@HA film also exhibited germicidal potential; the E. coli inhibition area was 18.0 ± 1.0 mm, while that of S. aureus was 10.5 ± 0.5 mm. Finally, the effect of Ag3PO4/Mg3(VO4)2/CNT@PVA/HA was investigated on the human lung cell line. Cell viability was 81.96% and 125%, respectively, when 5000 and 4.9 g ml−1 were administered. [ABSTRACT FROM AUTHOR]

The present study demonstrates the synthesis of ternary composites of zinc vanadate (Zn3V2O8) with silver (Ag) and carbon matrix originated from the Bengal gram bean extract (BGBE) using a facile, economic, and environmentally sustainable rotational chemical bath deposition (R−CBD) method. From the electrochemical studies, it is found that the Zn3V2O8−Ag@C demonstrated improved electrochemical performance with the specific capacitance (Csp) of 380.1 F g−1, energy density (ED) of 52.7 Wh kg−1, with power density (PD) of 882.3 W kg−1 at 3 mA cm−2 current density and good capacitive retention of 89.8 % over 3000 charge–discharge (GCD) cycles, which is remarkably higher than the other electrode materials (Zn3V2O8, Zn3V2O8−Ag, Zn3V2O8@C). The combined merits of conductive silver (Ag) nanoparticle and carbonaceous material from BGBE assist in enhancing the overall electrochemical performance of Zn3V2O8−Ag@C. The Zn3V2O8−Ag@C nanocomposite was used as electrode material for the fabrication of a flexible symmetric solid–state supercapacitor device (SSC). The SSC device delivered a Csp of 69.17 F g−1 with an energy density (ED) of 13.8 Wh kg−1 at a 2 mA cm−2 current density. Moreover, the SSC shows a 90 % capacitive retention over the continuous GCD cycles. [ABSTRACT FROM AUTHOR]

Due to the increasing demand for higher security and low-cost energy storage systems, the main research focus has been developing a suitable substitute for lithium-ion batteries. Aqueous zinc ion batteries (AZIBs) are considered the best alternative to lithium-ion batteries in large-scale energy storage devices. Owing to its high capacity, vanadate is a promising cathode material for AZIBs. The crystallographic orientation of cathode materials dramatically influences the rate performance and cycling life. Here, Mg0.57V5O12·2.3H2O (MgVO) with favorable (001) crystal orientation and significantly improved electrochemical performance is prepared by a simple stirring method. The crystal growth orientations of MgVO are altered by adjusting the aging time of the reactant solution. The (001)-orientated grain growth of MgVO delivers a 232.5 mA h g−1 capacity at 5 A g−1 with a 94% capacity retention rate after 1400 cycles. The zinc ion storage performance of MgVO demonstrates that the orientation-controlled method can design effective cathode materials for high-performance ZIBs. [ABSTRACT FROM AUTHOR]

Chitosan/AgVO3 nanocomposite thin films were synthesized via solution casting method using water as solvent. Silver vanadate (AgVO3) nanoparticles were prepared separately using a chemical precipitation technique. The structure and properties of the nanocomposite films were investigated using Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), swelling ratio tests, and antimicrobial assays. FTIR analysis confirmed the interaction between the amide I group of chitosan and AgVO3 nanoparticles. Increasing AgVO3 content resulted in decreased optical bandgap of the nanocomposite films. XRD patterns showed the amorphous nature of the nanocomposites. SEM images revealed evenly distributed AgVO3 nanoparticles within the chitosan matrix. The swelling ratio decreased with higher AgVO3 loading, suggesting improved hydrolytic stability. The nanocomposite films demonstrated potent antimicrobial activity against gram-positive and gram-negative bacteria as well as Candida fungus. The tunable optical properties, swelling behavior, and antibacterial effects spotlight the potential of chitosan/AgVO3 nanocomposites for versatile biomedical applications. [ABSTRACT FROM AUTHOR]

The title compound, (C4H12N)[V(C12H8N4O2)O2]H2O, was synthesized via aerial oxidation on refluxing picolinohydrazide with ethyl picolinate followed by addition of VIVO(acac)2 and diethylamine in methanol. It crystallizes in the triclinic crystal system in space group P.... In the complex anion, the dioxido-vanadium(V) moiety exhibits a distorted square-pyramidal geometry. In the crystal, extensive hydrogen bonding links the water molecule to two complex anions and one diethylammonium ion. One of the CH2 groups in the diethyl-amine is disordered over two sets of sites in a 0.7:0.3 ratio. [ABSTRACT FROM AUTHOR]

Printed zinc ion micro‐batteries (PZIMBs) possess characteristics such as miniaturization, customizability, and affordability, making them highly promising for the field of flexible electronic devices. Nevertheless, the current development of PZIMBs is seriously hindered by their limited areal capacity. In this study, PZIMBs with a high areal capacity are conducted based on 3D printing technology by optimizing the material properties, electrode ink formulation, and printing parameters. The cathode material, polyvinylpyrrolidone‐induced ammonium vanadate (P‐NVO) nanobelt, exhibits a high capacity of 457.3 mAh g−1 at 0.1 mA g−1, along with good cycling performance and rate capability. The double‐network hydrogel electrolyte, composed of crosslinked polyacrylamide‐polyvinylpyrrolidone (PAM‐PVP hydrogel electrolyte), demonstrates excellent ionic conductivity (107.22 mS cm−1), high stretchability (970%), and viscosity. The constructed PZIMBs exhibit a high areal capacity of 4.02 mAh cm−2 at 0.5 mA cm−2, along with good mechanical flexibility. Moreover, through the integration of PZIMBs with pressure sensors, an interactive system is developed that resembles electronic skin, and this integration enables practical applications of wearable devices. This study presents a novel approach for fabricating PZIMBs with high areal capacity, thereby contributing to and propelling the advancement of flexible energy storage. [ABSTRACT FROM AUTHOR]

A model catalyst composed of crystalline potassium pentavanadate (K3V5O14) supported on silica was studied to elucidate the effect of phase transitions on the performance of potassium‐promoted vanadia catalysts in propane oxidation. Operando calorimetry shows a clear correlation between a drop in activity and an increase in selectivity to propylene upon melting of the crystalline K3V5O14 phase under reaction conditions. The pentavanadate phase itself is not active in propane oxidation, neither in the solid nor in the molten state. The activity of the catalyst mainly originates from highly‐active, i. e., unselective VxOy surface species anchored to silica and formed during synthesis in addition to the supported pentavanadate phase. Melting of K3V5O14 leads to the coverage of these VxOy species preventing the overoxidation of propylene and leading to an increase in propylene selectivity. The change in catalyst properties is therefore due to a physical effect and not to a change in the chemical properties of the predominant crystalline phase. [ABSTRACT FROM AUTHOR]

A novel, highly sensitive, and precise electrochemical biosensor designed for the simultaneous determination of dopamine (DA) and uric acid (UA) via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods by using silver vanadate nanoparticles (AgVO3 NPs) fabricated glassy carbon electrode (GCE). AgVO3 NPs were prepared by eco-friendly simple green route approach by using Samanea saman (rain tree) tree pod extract. The structural morphology and characterization of as-prepared AgVO3 NPs were examined using powder XRD, FT-IR, FESEM, elemental mapping, EDAX, and HR-TEM analysis. Using DPV DA, and UA were simultaneously determined at AgVO3 NPs modified GCE under optimal conditions. The biosensor's low limits of detection for DA and UA were 0.019 and 0.012 µM, respectively. The developed sensor could be used as a platform for routine research into DA and UA because of its outstanding reproducibility and stability. The developed sensor was also employed for the analysis of DA and UA in serum and urine samples with excellent recovery. [ABSTRACT FROM AUTHOR]

The aim to access linked tetravanadate [V4O12]4− anion with mixed copper(II) complexes, using α-amino acids and phenanthroline-derived ligands, resulted in the formation of four copper(II) complexes [Cu(dmb)(Gly)(OH2)]2[Cu(dmb)(Gly)]2[V4O12]·9H2O (1) [Cu(dmb)(Lys)]2[V4O12]·8H2O (2), [Cu(dmp)2][V4O12]·C2H5OH·11H2O (3), and [Cu(dmp)(Gly)Cl]·2H2O (4), where dmb = 4,4′-dimethioxy-2,2′-bipyridine; Gly = glycine; Lys = lysine; and dmp = 2,9-dimethyl-1,10-phenanthroline. The [V4O12]4− anion is functionalized with mixed copper(II) units in 1 and 2; while in 3, it acts as a counterion of two [Cu(dmp)]2+ units. Compound 4 crystallized as a unit that did not incorporate the vanadium cluster. All compounds present magnetic couplings arising from Cu⋯O/Cu⋯Cu bridges. Stability studies of water-soluble 3 and 4 by UV–Vis spectroscopy in cell culture medium confirmed the robustness of 3, while 4 appears to undergo ligand scrambling over time, resulting partially in the stable species [Cu(dmp)2]+ that was also identified by electrospray ionization mass spectrometry at m/z = 479. The in vitro cytotoxicity activity of 3 and 4 was determined in six cancer cell lines; the healthy cell line COS-7 was also included for comparative purposes. MCF-7 cells were more sensitive to compound 3 with an IC50 value of 12 ± 1.2 nmol. The tested compounds did not show lipid peroxidation in the TBARS assay, ruling out a mechanism of action via reactive oxygen species formation. Both compounds inhibited cell migration at 5 µM in wound-healing assays using MCF-7, PC-3, and SKLU-1 cell lines, opening a new window to study the anti-metastatic effect of mixed vanadium–copper(II) systems. [ABSTRACT FROM AUTHOR]

Vanadium-chromium composite oxides have held much interest due to their distinctive catalytic properties, which depend on their morphology and crystal structure. During the hydrothermal synthesis, reducing agents play an important role in controlling the morphology and the crystal structure of vanadium-chromium oxides. In this work, nanocrystalline chromium vanadate (CrVO4) were prepared by a simple one-pot hydrothermal method based on the reaction between V2O5 and CrO3. Three different CrVO4 crystal structures, including orthorhombic CrVO4, monoclinic CrVO4, and mixed-phased-CrVO4 were obtained by using different reducing agents. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed that nanocrystalline monoclinic CrVO4 was obtained using tartaric acid as the reducing agent. Catalytic properties of nanostructured CrVO4 were investigated for the vapor phase ammoxidation of 2-chlorotoluene to 2-chlorobenzonitrile. The monoclinic CrVO4 nanostructures exhibited excellent catalytic performance due to the proper distribution of V-O-Cr bond. It was one of the most efficient binary catalysts for such vapor phase ammoxidation processes to the best of our knowledge, and may have great potential for the ammoxidation of halogen-substituted toluenes. Monoclinic CrVO4 nanostructures are controllably prepared by hydrothermal process using tartaric acid as reductant and exhibit excellent catalytic performance for ammoxidation of 2-chlorotoluene. [ABSTRACT FROM AUTHOR]

The aim of this research is to explore the potential of ZrB2-SiC-based ceramic coatings as a protective layer for Inconel 718 substrates. The study focuses on the use of shrouded plasma spraying technology to deposit the coating and investigates the effect of exposure to molten sulfate-vanadate salts (45% Na2SO4 and 55% V2O5) on its properties. The tribological behavior and corrosion resistance of the coated samples were evaluated, and the results revealed that the ZrB2-SiC coating showed resistance to hot corrosion. Upon exposure to the molten salt mixture, the ZrB2-SiC coating was found to interact with V2O5 and Na2SO4, forming binary oxide phases, such as NaVO3 and SiO2. The formation of the ZrO2 monoclinic phase was observed due to the leaching of B2O3 from the ZrB2-SiC coating. However, the physical properties of ZrB2-SiC were found to prevent the penetration of the molten salt, thus reducing its corrosive effect. Overall, the results indicate that ZrB2-SiC-based ceramic coatings have the potential to offer effective protection to Inconel 718 substrates against hot corrosion in harsh environments. [ABSTRACT FROM AUTHOR]

Bismuth vanadate with suitable band edges is one of the efficient photocatalysts for water oxidation. Establishing heterojunction can improve electron diffusion lengths and photocatalytic ability of BiVO 4. In this work, nickel molybdenum oxide (Ni–Mo–O) and BiVO 4 heterojunction is established by the hydrothermal process with different nickel to molybdenum precursor ratios. The Ni–Mo–O/BiVO 4 electrode is applied as photoanodes for water oxidation. The growth mechanism of Ni–Mo–O on BiVO 4 surface is proposed. The Ni–Mo–O deposition amount is optimized regarding to light absorbance and charger transportation. The largest photocurrent density of 1.72 mA/cm2 at 1.23 V RHE is obtained for the optimal NiMoO 4 /BiVO 4 electrode (NM12) in the electrolyte without hole scavenger, while the pure BiVO 4 electrode only shows a photocurrent density of 0.90 mA/cm2. The NM12 electrode even presented an impressive photocurrent density of 5.39 mA/cm2 at 1.23 V RHE in the electrolyte with the hole scavenger, owing to the abundant active sites and higher light absorbance as well as the favorable synergistic effects from its suitable Ni to Mo ratio. The NM12 electrode also shows excellent long-term stability with the photocurrent retention of 83% after illumination for 6500 s. This work opens a blueprint for establishing a novel heterojunction with the adjustable metal ratio and coverage on BiVO 4. [Display omitted] • Nickel molybdenum oxide (Ni–Mo–O) and BiVO 4 heterojunction is made by hydrothermal. • Ni–Mo–O/BiVO 4 photoanode with varied Ni to Mo ratios is used for water oxidation. • The growth mechanism of Ni–Mo–O on BiVO 4 surface is proposed. • Photocurrent density of 5.39 mA/cm2 at 1.23 V RHE is got for optimal NM12 electrode. • The NM12 electrode shows an excellent photocurrent retention of 83 % after 6500 s. [ABSTRACT FROM AUTHOR]

Rare-earth orthovanadate nanoparticles (NPs) demonstrate unique combination of physicochemical characteristics and biological activity. The redox properties and low toxicity of orthovanadates in nanoform allow considering them as perspective nanomedicine modalities. The local microenvironment in biological media and the way NPs enter the organism determine their biological efficiency. Numerous studies deal with interaction of vanadium species and bio-molecules in serum, however, the interplay between orthovanadate NPs and serum compounds is still under debates. Here we investigate the effect of serum proteins on aggregative stability of three types of negatively charged orthovanadate NPs (spherical, spindle-like, and rod-like). Size of NPs was estimated by light-scattering methods in solutions, biologically relevant buffers and media. Some geometry- and size-dependent peculiarities of NPs behavior in different solutions were found. Modeling the proteins–NPs interactions for main serum proteins at threshold Ca2+ and Mg2+ concentrations revealed nonlinear aggregative behavior depending on protein concentrations. In Krebs-Ringer buffer the behavior of the rod-like NPs differs strongly on the behavior of more isometric NPs (spherical and spindle-like). The hydrodynamic diameter changes are non-linear and rod-like NPs have specific behavior in serum-like protein mixtures. These effects are associated with shape-specific involvement of different forces (including electosteric, hydrophobic, osmotic and recoil ones) in stabilization process. [ABSTRACT FROM AUTHOR]

Cobalt, nickel, manganese and zinc vanadates were synthesized by a hydrometallurgical two-phase method. The extraction of vanadium (V) ions from alkaline solution using Aliquat® 336 was followed by the production of metal vanadates through precipitation stripping. Precipitation stripping was carried out using solutions of the corresponding metal ions (Ni (II), Co (II), Mn (II) and Zn (II), 0.05 mol/L in 4 mol/L NaCl), and the addition time of the strip solution was varied (0, 1 and 2 h). The time-dependent experiments showed a notable influence on the composition, structure, morphology and crystallinity of the two-dimensional vanadate products. Inspired by these findings, we selected two metallic vanadate products and studied their properties as alternative cathode materials for nonaqueous sodium and lithium metal batteries. [ABSTRACT FROM AUTHOR]

Transition metal vanadates (MVs) possess abundant electroactive sites, short ion diffusion pathways, and optical properties that make them suitable for various electrochemical (EC) and photoelectrochemical (PEC) applications. While these materials are commonly used in energy storage devices like batteries and capacitors, their shape‐controlled 1D and 2D morphologies have gained equal popularity in water splitting (WS) technology in recent times. This review focuses on recent progress made on various first‐row (3d, 4 s) transition metal vanadates (t‐MVs) having controlled one‐dimensional (fiber, wire, or rod) and two‐dimensional (layered or sheet) morphologies with a specific emphasis on copper vanadates (CuV), cobalt vanadates (CoV), iron vanadates (FeV), and nickel vanadates (NiV). The review covers different aspects of shape‐controlled 1D and 2D t‐MVs including optoelectrical properties, wet chemistry synthesis, and electrochemical (EC‐WS) and photoelectrochemical water splitting (PEC‐WS) performance in terms of onset potential, overpotential, and long‐term stability or high cyclic performance. The review concludes by providing some possible thoughts on how to promote the water‐splitting attributes of shape‐controlled t‐MVs more effectively. [ABSTRACT FROM AUTHOR]

In this study, the unique thermoelectric properties along with structural, electronic, and photoluminescence properties of divanadate oxides XV2O6 (X = Mg, Ca, and Ba) have been investigated using DFT and experimental routes for waste heat recovery applications. For the synthesis process, the solid-state reaction technique was employed and the monoclinic structure of the synthesized oxides was confirmed by the XRD results. The formation of well-shaped particles was demonstrated by SEM images and the presence of Mg, Ca, Ba, V, and O with the proper compositions was confirmed by EDS mapping. The calculated bandgap values for MgV2O6, CaV2O6, and BaV2O6 were 3.20 eV, 2.14 eV, and 1.76 eV, respectively. To see how atomic orbitals affect the creation of bands, total and partial density of states calculations were also made. The BoltzTraP algorithm within Wien2k was used to study transport properties. Photoluminescence (PL) was done to analyze the optical behavior of synthesized oxides. For all the divanadate oxides XV2O6 (X = Mg, Ca, Ba), productive values for the Seebeck coefficient (S), electrical conductivity (σ), power factor (PF), and figure of merit (ZT) have been observed. The semi-metallic nature, low synthesis cost, and thermoelectric results demonstrate that the studied oxides have exceptional potential for waste heat recovery applications and can be very efficient in energy harvesting devices, especially in thermoelectric generators. [ABSTRACT FROM AUTHOR]

Photoanodes are a critical part of the photoelectrochemical (PEC) water splitting technology that drives the conversion of solar energy to hydrogen, while bismuth vanadate (BiVO4) is one of the most promising photoanode materials available. Here, we provide a simple spin-coating method to modify the PEC performance of BiVO4 by coating ultrathin cobalt pyrophosphate (Co2P2O7) nanosheets as a co-catalyst layer onto the surface of BiVO4. The Co2P2O7/BiVO4 composite photoanode achieved a photocurrent density of 3.93 mA cm−2 at 1.23 V versus RHE, which is 2.5 times higher than bare BiVO4 and considerably better than Co-Pi/BiVO4 and CoOx/BiVO4, with an improved charge injection efficiency of 71%. The key to the substantial enhancement of PEC performance is that Co2P2O7 nanosheets accelerate the charge transfer process all over the BiVO4 surface, not only as a water oxidation catalyst (OEC) layer accelerating the kinetic rate of the oxygen evolution reaction (OER) at the junction with the water, but also suppressing the rate of photogenerated electron–hole recombination at the Co2P2O7/BiVO4 junction. A potential mechanism for the enhanced PEC performance of Co2P2O7 nanosheets is proposed, and this work provides assistance in the design of transition metal pyrophosphate, cobalt-based nanomaterial morphologies to enhance the PEC properties of BiVO4. [ABSTRACT FROM AUTHOR]

Background: The presence of type 2 diabetes mellitus increases the risk of developing the colon cancer. The main objective of this study was to determine the role of sodium orthovanadate (SOV) in colon cancer associated with diabetes mellitus by targeting the competitive inhibition of PTP1B. Methods: For in vivo study, high fat diet with low dose streptozotocin model was used for inducing the diabetes mellitus. Colon cancer was induced by injecting 1,2-dimethylhydrazine (25 mg/kg, sc) twice a week. TNM staging and immunohistochemistry (IHC) was carried out for colon cancer tissues. In vitro studies like MTT assay, clonogenic assay, rhodamine-123 dye assay and annexin V-FITC assay using flow cytometry were performed on HCT-116 cell line. CAM assay was performed to examine the anti-angiogenic effect of the drug. Results: Sodium orthovanadate reduces the blood glucose level and tumor parameters in the animals. In vitro studies revealed that SOV decreased cell proliferation dose dependently. In addition, SOV induced apoptosis as depicted from rhodamine-123 dye assay and annexin V-FITC assay using flow cytometry as well as p53 IHC staining. SOV showed reduced angiogenesis effect on eggs which was depicted from CAM assay and also from CD34 and E-cadherin IHC staining. Conclusions: Our data suggest that SOV exhibits protective role in colon cancer associated with diabetes mellitus. SOV exhibits anti-proliferative, anti-angiogenic and apoptotic inducing effects hence can be considered for therapeutic switching in diabetic colon cancer. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cadmium ions may be discarded to the environment with living organisms from fossil fuel combustion, phosphate fertilizer and battery industries. It is urgent and essential to develop a sensitive and rapid method for monitoring Cd2+ level in aquatic environments and biological systems. Neodymium vanadate possesses good catalytic performance for the electrocatalysis of heavy metal ions. Single crystalline Nd vanadate nanoribbons were obtained by a facile approach and used as electrode materials for electrochemical detection of Cd2+. RESULTS: The Nd nanoribbons with tetragonal NdVO4 phase possess length, width and thickness of longer than 10 μm, 200 nm to 1.5 μm and 50 nm, respectively. Nd vanadate nanoribbons can serve as a good electron transfer interface. An anodic peak is located at +0.56 V at the Nd vanadate nanoribbon‐modified electrode in 0.1 mol L−1 KCl electrolyte containing 1 mmol L−1 Cd2+ by square wave voltammetry technique. The Nd vanadate nanoribbon‐modified electrode exhibits a linear range of 0.01–1000 μmol L−1 and a detection limit of 0.29 nmol L−1, with good stability, reproducibility and selectivity for Cd2+ detection. CONCLUSION: The optimal measurement conditions including the pH value of the KCl solution, deposition time, deposition potential and standing time, which are pH 1, 180 s, −1.0 V and 60 s, respectively. The Nd vanadate nanoribbon‐modified electrode shows great application potential for detecting heavy metal ions in liquid environments. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Highlights La3+/Na+ bimetallically doped vanadate, designed for the first time, is promising in many electrochemical applications (e.g., batteries, electrochromics). This is the first report of electrochromic displays employing bimetallically doped vanadate. It is demonstrated for the first time that zinc dendrites and vanadate dissolution are significantly inhibited by employing an aqueous hybrid Zn2+/Na+ electrolyte.

The pure V3+ species boosted the high-efficiency dehydrogenation of V/γ-Al 2 O 3 catalyst. [Display omitted] The vanadium-based dehydrogenation (DH) catalyst is becoming a promise alternative to the industrial used Pt- and Cr-based catalysts, due to lower cost and less environmental threat. However, the low DH activity hampered the industrial application of vanadium-based catalysts. Herein, for the first time, we introduce a method to prepare high-efficiency vanadium-based catalyst by constructing pure V3+ species on γ-Al 2 O 3 through treatment of as-prepared thiovanadate. The V3+ species contributes to not only enhancing the DH activity, but also fabricating the V3+-O/S acid-base pair with ideal strength and stability. The isobutene yield can reach as high as 56.9 wt%. Only Lewis acid is recognized on V3+/Al 2 O 3 catalyst, while no Brønsted acid remains. The side-reactions are consequently inhibited, and the selectivity to isobutene is improved. Besides, with the increase of vanadium loadings, the Lewis acid content increases at first and then decreases, and the content of acid sites in middle strength keeps decreasing. Though the deposited coke on V3+/Al 2 O 3 was just 2.5 wt% during 8.5 h consecutive DH reaction, the valence state of vanadium was still influenced and the fraction of inert V4+ species increased steadily. This study will improve the potential for industrial application of vanadium-based DH catalyst, and offer theoretical guidance for optimization of ideal DH catalysts. [ABSTRACT FROM AUTHOR]

Pure micro- and nanocrystalline powders of the layered-kagome zinc orthovanadate BaZn3(VO4)2(OH)2 have been successfully prepared and thoroughly characterised. Microstructured samples (BaZn3-MPs) have been produced by hydrothermal reaction using synthetic martyite Zn3V2O7(OH)2·2H2O as the starting reagent. Nanoparticles (NPs) with an average size of ≈ 60 nm (BaZn3-NPs-7h) or ≈ 50 nm (BaZn3-NPs-25min) have been obtained by using a coprecipitation method at ambient pressure, and by varying the stirring time. Rietveld refinements of X-ray diffraction data indicate that micro- and nanostructured BaZn3(VO4)2(OH)2 both crystallize in a Rm structure very similar to that of the known layered-kagome compound BaCo3(VO4)2(OH)2. Transmission electron microscopy observation of BaZn3-NPs-7h and BaZn3-NPs-25min reveals crystallized NPs with homogenous distributions of Ba, Zn, and V elements. FT-IR and Raman spectra show subtle differences between micro- and nanostructured samples which cannot be linked to any differences in the average crystal structures. The high resolution 51V MAS NMR spectrum of BaZn3-MPs shows a single isotropic line attributed to VO43− groups with C3v point group. The spectra of the nanostructured samples reveal the presence of a weak additional signal which decreases in intensity with increasing the NPs size, and which has been tentatively assigned to the presence at the surface of the NPs of a small amount of V5+ ions in a different chemical environment. Nanostructuring also impacts the optical properties of BaZn3(VO4)2(OH)2. The UV-vis absorption spectra of NPs exhibit an additional weak transition in the visible domain which is not observed for the microstructured sample. [ABSTRACT FROM AUTHOR]

Chitosan (Cs) and hydroxypropyl cellulose (HPC) blend films were created and incorporated with copper vanadate nanoparticles. The films were characterized using various techniques, including x‐ray diffraction (XRD), attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR), TEM, SEM, UV/vis spectroscopy, dielectric properties, and AC conductivity. The XRD analysis showed that the prepared films had amorphous characteristics. FT‐IR spectra indicated interactions between the Cs/HPC virgin polymers and copper vanadate nanoparticles. TEM analysis showed that the most prevalent size range of the nanoparticles was 20–60 nm. SEM micrographs revealed surface homogeneity at lower copper vanadate nanoparticle contents but increased inhomogeneity with higher contents. The prepared films showed a decrease in the optical energy gap and an increase in refractive index with increasing copper vanadate nanoparticle content. Copper vanadate nanoparticles enhance AC conductivity in Cs/HPC polymer blend. Dielectric analysis proved the suitability of the films for electroactive polymer applications. Highlights: The casting process was used to prepare Cs/HPC—copper vanadate NPs films.XRD shows increased amorphousness post‐addition of copper vanadate NPs.SEM images revealed an increase in inhomogeneity with higher contents of copper vanadate NPs.The optical band gap decreased as the content of copper vanadate NPs increased.Copper vanadate nanoparticles greatly improve electrical conductivity and relaxation time. [ABSTRACT FROM AUTHOR]

Vanadate oxides with low price and high theoretical capacity are competitive cathodes for aqueous zinc-ion batteries (AZIBs). However, the existing problems such as sluggish Zn2+ ion mobility, weak conductivity, and complicated flexible electrode preparation hinder the development of their practical applications in flexible AZIBs (FAZIBs). Herein, sodium-ion and polyaniline are co-inserted into ammonium vanadate (NaNVO-PANI) nanoarrays, which can serve as the novel freestanding cathodes for FAZIBs. By virtue of synergistic pillar effect of sodium ions and polyaniline, the interplanar spacing of NaNVO-PANI expands to "13.8 A. Both experimental data and theoretical calculation confirm that the optimal spacing of NaNVO-PANI can boost enhance the electronic conductivity and reduce Zn2+ diffusion barrier. As expected, the resulting coin-type AZIBs exhibit high capacity of 610.7 mAh g-1 at 0.5 A g-1 and remarkable capacity retention of 98% after 5000 cycles at 5 A g-1. More encouragingly, quasi-solid-state FAZIBs with sandwich structure are assembled, achieving impressive energy density of345.59 Wh kg-1 at a power density of380.46 W kg-1. This study is of great significance for developing high-performance vanadium-based electrode for wearable FAZIBs. [ABSTRACT FROM AUTHOR]