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Aqueous zinc ion batteries are attracting broad interest in stationary energy storage where low cost, robust security, and satisfactory capacity matter most. However, metal zinc anodes suffer from destructive dendrite issues during repeated charging/discharging process, decreasing the cycle life of batteries. Herein, smoother zinc plating/striping behaviors are achieved by group modification in the structural unit of the polymer separator. Experimental results and theoretical simulations reveal that the polymer skeleton can release zinc ion more easily when modified with carbonylation side groups and contribute to much faster zinc ion transfer capability. Typically, symmetric Zn cells with a thin thickness separator of 21 µm exhibit ultralong cycle life over 2800 h at 1 mA cm−2 within 1 mAh cm−2 and 300 h under a high current density of 5 mA cm−2 within high areal capacity of 3 mAh cm−2. Full cells using a sodium vanadium oxide cathode also show stable reversible charging/discharging performance after 2000 cycles at 3 A g−1. This work is expected to inspire promising strategies in molecular design in polymeric separator toward stabilizing metal anodes beyond this anode itself. [ABSTRACT FROM AUTHOR]

Multivalent ion batteries (e.g., Zn2+, Ca2+) are gaining great attention owing to their potentially high capacity, cheap cost, and good safety. However, significant disparities exist in achieved capacity, voltage, and kinetic performance within zinc and calcium ion electrolytes. Herein, the electrochemical and kinetic properties of Zn2+ and Ca2+ in aqueous electrolytes are investigated using a single‐crystal V2O5 (V2O5·Pyridine, PVO) model material with stable large interlayer spacing. It is found that the discharge‐specific capacity in 1 m Zn(ClO4)2 aqueous solution is 247.3 mAh g−1 at 0.3 A g−1, which is remarkably higher than 158.4 mAh g−1 in 1 m Ca(ClO4)2. Mechanistic studies show that in aqueous ZIB, H+ is intercalated first, followed by the generation of Zn4(OH)7ClO4, and finally H+ and Zn2+ are co‐intercalated. But in aqueous CIB, H+ dominates the intercalation process. It is found that six times more Zn2+ than Ca2+ is intercalated into PVO, owing to its smaller radii and its relative higher intercalation potential (Zn2+ @‐0.34 V, Ca2+ @‐0.65 V vs.. Ag/AgCl), giving it a higher specific capacity. Furthermore, density functional theory calculations demonstrate lower intercalation energies for Ca2+ (−6.67 eV) compared to Zn2+ (−1.85 eV), explaining the lower intercalation potential of Ca2+. [ABSTRACT FROM AUTHOR]

The corrosion protection behaviour of electrogalvanised steel sheets (EG) by the tetravalent vanadium ion was investigated. Immersion of the bare EG in a NaCl solution revealed that the addition of vanadium(IV) oxide sulphate to the solution led to a transition of the open circuit potential to less noble and the formation of vanadium oxides on the EG surface. The oxide layer included not only vanadium(III) oxides but also a small amount of ZnO, indicating that Zn on the EG surface was oxidised while the vanadium(IV) species was reduced to the vanadium(III) species. The corrosion current density of the EG with the adhering vanadium(III) species was one order of magnitude smaller than that of the bare EG, clearly suggesting that zinc corrosion was reduced by suppressing the reduction reaction of dissolved oxygen. The vanadium(IV) species could be a candidate as a self-healing inhibitor for chromate-free coating technologies by controlling the coupling of Zn oxidation and vanadium(IV) reduction. [ABSTRACT FROM AUTHOR]

Titanium is characterized by poor wear resistance which restricts its application. Ceramic conversion treatment (CCT) is used to modify the surface; however, it is a time-consuming process. In this work, a thin vanadium layer was pre-deposited on the commercial pure titanium (CPTi) samples' surface, and it increased the oxygen absorption significantly and assisted in obtaining a much thicker oxide layer than those samples without a V layer at the treatment temperatures of 620 °C and 660 °C. The oxidation of the samples pre-deposited with the V layer had a much higher oxidation rate, and V was evenly distributed in the oxide layer. After CCT, all samples had a low wear volume and stable coefficient of friction in comparison to the untreated CPTi sample. A slightly higher wear area in the wear track was observed on the V pre-deposited samples than those samples without vanadium, especially those with a thicker oxide layer (>4 µm). This might be associated with defects in a thicker oxide layer and insufficient support from a shallower oxygen diffusion zone or hard debris created at the initial stage. Vanadium in the oxide layer reduced the contact angles of the surface and increased the wettability significantly. [ABSTRACT FROM AUTHOR]

As a typical Correlated Electron Material, vanadium dioxide was discovered to demonstrate metalinsulator transition at a relatively low temperature. The transition occurs from an insulating monoclinic phase to a metallic tetragonal phase (rutile structure) upon heating with the rearrangement of vanadium ions along an axis of the monoclinic lattice. The phase change corresponds to a colossal resistivity drop by over four orders of magnitude as well as other dramatic property changes, which can be reversible via a natural cooling process. Therefore, vanadium dioxide has attracted extensive attention for its applications in highly sensitive smart devices that can abruptly respond to diverse external stimuli. In recent years, rapid advancement in the fabrication and property modulation of vanadium dioxide has greatly facilitated its applications in many aspects, such as thermal sensing, thermochromics, electronics, and multiple-response mechanics. The optical properties of thin vanadium dioxide films VO2 were researched using the modulation polarimetry technique. For VO2 thin film deposition the two-step method was used. VO2 films were grown on quartz glass substrates by magnetron sputtering of the VO2 target. The films had different modifications of composition, structure, morphology, and optical properties due to the manufacturing technology. The angular dependence of the reflection coefficients of electromagnetic radiation of s- and p- polarizations and their difference for different wavelengths was measured in the paper. The polarization characteristics were simulated by a matrix transformation of the Fresnel formulas. The values of the refractive and absorption indices of the films were obtained from the condition of the best agreement between the experiment and mathematical simulation. Atomic force microscope and X-ray diffraction analysis were used as standard analytical methods. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAP) contains abundant defect sites and easily releases hydroxyl groups to produce new vacancies under calcination at high temperature. The highly dispersed VOx/HAP catalyst was prepared by an impregnation method using these defects as inducement. VOx species with different structures were analysed by XRD, XPS, H2‐TPR, Raman and UV–vis spectroscopy. At low calcination temperatures (500 °C and 600 °C), the V species are mainly V2O5 crystals. At high calcination temperatures (above 700 °C), VOx on the HAP surface fills these defect sites and strongly interacts with HAP to form Ca−O−V or P−O−V bands. These scattered defects improved the dispersion of V species. These highly dispersed VOx/HAP catalysts were used for oxidative dehydrogenation (ODH) of cyclohexane to cyclohexene. The highly dispersed VOx/HAP catalyst showed a high selectivity for cyclohexene, and the selectivity reached 48.2 % when the conversion of cyclohexane was 13.1 % at 410 °C. [ABSTRACT FROM AUTHOR]

In the search for non‐enzymatic alternatives to glucose oxidase, reliable and microchip‐compatible approaches to catalyst development are highly desirable. Herein, the electrochemical behavior of thin films of VOx deposited by molecular beam epitaxy (MBE) on glassy carbon electrodes is reported. A process of partial etching during polarization is observed. Thereafter, highly active and stable traces of VOx act as catalytic centers for glucose electrooxidation. A mechanistic description of the electrochemical process is proposed based on evidence provided by voltammetric measurements. The sensors are calibrated both with potentiometric and amperometric techniques, the former showing a wide linear range (1–10 mM), good sensitivity (14.93 ± 0.39 µA cm−2 × mM–1) and a limit of detection (0.32 m‐M). Unlike most metal oxides, it is shown that VOx on glassy carbon is capable of successfully oxidizing glucose at −0.4 V. Such a one‐of‐kind behavior can have important ramifications for energy‐efficient integrated electrochemical sensors and non‐enzymatic glucose sensing as a whole. [ABSTRACT FROM AUTHOR]

Pre‐intercalating ions between VO layers is considered to be an effective strategy to modulate the interlayer spacing of 2D vanadium oxides. However, the rigid pre‐intercalated ions hardly keep stable during repeated charging/discharging process and their sizes limit the extent of interlayer spacing expansion, which inevitably lead to poor rate capability and cycle stability. In this work, aliphatic diamines are adopted as pre‐intercalated guests to elastically modulate the interlayer spacing of VO layers by tuning the chain length of the organic diamine molecules. Benefiting from the strong interaction between the terminal doubly protonated amine and the polar negative oxygen bridge of the VO layers, the aliphatic diamine molecules can act as a structural stabilizer between the layers and boost fast Na ion diffusion (10−8 to 10−10 cm2 s−1). The sodium ion battery based on the first synthesized 1,6‐hexanediamine pre‐intercalated vanadium oxide supported on nickel foam hybrid cathode achieves a large specific capacity of 597 mAh g−1 at 0.09 A g−1, as well as superior rate performance and cycling stability. This work provides a strategy to elastically modulate 2D layered materials with tunable interlayer spacing for batteries based on large‐size‐ions. [ABSTRACT FROM AUTHOR]

Here, we have reported a simple and one-step hydrothermal method for preparing a highly uniform sodium zirconosilicate mesoporous sorbent supported with vanadium oxide nanoparticles (VO2). The results showed the formation of NPs with a surface area of 73.21 m2/g and with a particle size ranged from 67 to 80 nm. Furthermore, the proposed fabricated composite has been used to significantly remove the cesium and strontium ions from the aqueous solution by a batch method. The phase and structural characteristics of the VO2/zirconosilicate nanocomposites were well studied by using XRD, SEM, HRTEM, and nitrogen adsorption techniques. The results showed that the cesium and strontium ions were efficiently adsorbed by mesoporous VO2/zirconosilicate ion exchanger at a natural and wide pH ranges. Various kinetic and isotherms models have been developed to highlight the adsorption process of cesium and strontium ions. The fabricated zeolitic materials exhibited an adsorption capacity of 30.5 and 22.2 mg g−1 for Cs(I) and Sr(II), respectively. The collected data showed that the synthesized VO2/zirconosilicate has the maximum potential to properly remove Cs(I) and Sr(II) from the aqueous media. A microporous VO2/zirconosilicate nanocomposite adsorbent has been designed for efficient removal of cesium and strontium from contaminated samples. The synthesized nanocomposite indicated a highly ability to remove Cs(I) and Sr(II) ions in ultra-dilute solutions. [ABSTRACT FROM AUTHOR]

A non-conventional mechanochemical processing technique was used to prepare fine-grain of mixed iron and vanadium oxides with a lead titanate system at boron oxide matrix. The structures of the ball milled samples were analyzed at different milling times and temperatures. After 30h of mechanical milling, the vanadium peaks completely disappeared, and partially supersaturated solid solution was formed. The average crystallite size of the 30h milled sample calculated from XRD patterns decreases rapidly from 3.72 μm to 69.4 nm while the crystallite size of the 50h was 26.3 nm. The DSC curve confirms the mechanochemical reactions. Metastable phases of lead vanadium oxide obtained after heat treatment with average crystallite size 65 nm in a non-crystalline matrix. The conductivity of the heat-treated samples increases with increasing heating temperature. The conductivity of all the prepared samples was found to be consistent with small polaron hopping, Mott's theory which confirmed by studying the power law behavior of its AC conductivity. The AC conductivity increases with increasing temperature and frequency. [ABSTRACT FROM AUTHOR]

The low cost and intrinsic safety of rechargeable aqueous zinc‐ion batteries (ZIBs) contribute to their significant potential in grid‐level energy storage systems. However, the limited cathode options still hinder the development of ZIBs, which always delivers poor rate capacities and cycling stability. Herein, Monoclinic phase H3.78V6O13 microspheres with a stable internal framework and intrinsic metallic properties as a high‐performance cathode for ZIBs are proposed and utilized. The reversible Zn2+insertion/de‐insertion mechanism in H3.78V6O13through ex situ X‐ray diffraction, X‐ray absorption near‐edge structure, and in situ Raman involves the enlargement/shrink of interplanar distance, the decrease/increase of the V valance, and the open/recombine of V─O/V─V bonds. Further, experiments and theoretical calculations elucidate the superior electrochemical performance and extraordinary reaction kinetics in H3.78V6O13. The as‐prepared H3.78V6O13 cathode delivers high specific capacity of 406 mAh g–1 at 0.1 A g–1, excellent structure stability with 100% manifested after 120 cycles at 0.5 A g–1, 72.9% retained after 15 000 cycles at 10 A g–1. This research offers distinctive perspectives on the development of high‐performance cathode materials for ZIBs and enhances the understanding of the electrochemical reaction mechanisms of vanadium oxides. [ABSTRACT FROM AUTHOR]

Active thermal radiation control of an object requires adaptive and flexible strategies to cope with emissivity engineering and its temperature dependence. On the other hand, the concept of digital coding allows a high degree of freedom in manipulating the interacting physical quantities based on local discretized features. Learning from this idea, this study put forward the manipulation of spatial infrared emission based on tungsten (W)‐doped VO2 films toward thermal coding. Here, 1‐bit coding worksheets created by low‐emissivity, that is, code '0′, and high‐emissivity, that is, code '1′, shift with materials metal‐insulator phase transition to encode emissive information in the temperature domain. It is shown experimentally that this concept has marked implications on thermal radiation control at Mid‐infrared, among which are as follows: digital anti‐counterfeiting by in‐plane spatial coding of a group of VO2 thin films with various W‐doping density and infrared camouflage by out‐of‐plane spatial coding of them. With a W‐doping gradient of 0%, 0.8%, and 1.7%, the three‐phase transition points in the temperature domain, that is, 72, 63, and 45 °C, give a remarkable modulation range of 27 °C. These phenomena pave the way for new classes of emissivity engineering for more accurate, flexible, and adaptive thermal radiation control. [ABSTRACT FROM AUTHOR]

Vanadium oxides (VOx) feature the potential for high‐capacity Zn2+ storage, which are often preintercalated with inert ions or lattice water for accelerating Zn2+ migration kinetics. The inertness of these preintercalated species for Zn2+ storage and their incapability for conducting electrons, however, compromise the capacity and rate capability of VOx. Herein, Ni‐BTA, a 1D conductive metal–organic framework (c‐MOF), is intercalated into the interlayer space of VOx by coordinating organic ligands with preinserted Ni2+. The intercalated Ni‐BTA improves the conductivity of VOx by π–d conjugation, facilitates Zn2+ migration by enlarging its interlayer spacing, and stabilizes the crystal structure of VOx as interlayer pillars, thus simultaneously enhancing the material's rate capability and cycling stability. Meanwhile, a dual reaction mechanism of Zn2+ storage, i.e., the redox of V5+/V3+ in VOx and the rearrangement of chemical bonds (CN/CN) in Ni‐BTA, collaboratively contributes to an enhanced capacity. Consequently, this Ni‐BTA‐intercalated VOx material exhibits a high Zn2+ storage capacity of 464.2 mAh g−1 at 0.2 A g−1 and an excellent rate capability of 272.5 mAh g−1 at 5 A g−1. This work provides a general strategy for integrating c‐MOFs with inorganic cathode materials to achieve high‐capacity and high‐rate performance. [ABSTRACT FROM AUTHOR]

(2, 3-DN)0.23V2O5·0.22H2O (DN = dinaphthoquinone) nanosheets with rich oxygen vacancies (abbreviated as (2, 3-DN)-VO) were synthesized by a facile one-step solvothermal method. Rietveld refinement illustrates the successful intercalation of 2, 3-DN into the layered vanadium oxide. (2, 3-DN)-VO can deliver a high specific capacity of 440 mAh g−1 at 0.1 A g−1 with a capacity retention of 92.6% over 2300 discharge/charge cycles at 10 A g −1 when used as zinc-ion battery cathode. It benefits from the dual-activity of naphthoquinone and vanadium oxide. Meanwhile, the encapsulation of naphthoquinone into the interlayer channel of vanadium oxide not only can expand the interstitial spacing for the diffusion of Zn2+, but also prevent the dissolution of the organic species into the electrolyte. [ABSTRACT FROM AUTHOR]

Vanadium phosphorus oxide (VPO) was immobilized on SBA-15 via a facile impregnation process. The structure and VPO species on SBA-15 were characterized by XRD, TEM, BET, FTIR and XPS techniques. It was found the VPO/SBA-15 catalysts maintained the two-dimensional hexagonal structure of SBA-15, and the supported VPO species existed in a highly dispersed amorphous state. VPO/SBA-15 catalyst was tested for the ammoxidation of dichlorotoluenes (DCTs) to corresponding dichlorobenzonitriles (DCNs) in a lab-scale tube reactor. Compared with VPO/SiO2 (large-pore silica-supported VPO), VPO/SBA-15 exhibited appreciable enhancement in the catalytic performance due to the unique channel structure of SBA-15. The yield and selectivity toward 2,4-DCN increased by 7% and 6%, while toward the sterically hindered 2,6-DCN increased by 7% and 13%, respectively. [ABSTRACT FROM AUTHOR]

The reaction of dehydrogenation and oxidative dehydrogenation of isopropyl alcohol on molybdenum-vanadium oxide catalysts has been studied. It found that the dependences of isopropyl alcohol conversion and propylene yields on the atomic ratio of molybdenum to vanadium in reaction of dehydrogenation of isopropyl alcohol have the form of a curve with two maxima on samples Mo-V=2-8 and Mo-V=6-4. To characterize the acidic properties of the surface of molybdenum-vanadium oxide catalysts, their activity in the reaction of butene-1 isomerization into butenes-2 was also studied. It showed that on molybdenum-vanadium catalysts the dependence of the yield of 2-butenes on the ratio of molybdenum to vanadium also had the form of a curve with two maxima. The activities of molybdenumvanadium oxide catalysts were compared with their acidic properties. It revealed that on binary molybdenum-vanadium oxide catalysts in the reaction of isopropyl alcohol dehydrogenation the increase of surface acidity led to the increase in acetone yield and the decrease in propylene yield. In the reaction of oxidative dehydrogenation of isopropyl alcohol, the increase in surface acidity led to the increase in acetone yield, while propylene yield practically did not change. [ABSTRACT FROM AUTHOR]

Aerobic oxidative desulfurization (AODS) promises a sustainable alternative desulfurization process for fuel, yet is still limited by high temperature and low efficiency for oxygen activation. Here we report that the monolayer two-dimensional vanadium carbide (V2CTx) MXene can emerge as a robust and stable catalyst for the oxidation of thiophenic compounds with oxygen in air as an oxidant. The catalyst performs a higher mass specific activity over the state-of-art vanadium oxides, activates the reaction at 70 °C, and achieves effective conversion of various sulfides under mild condition. Coupling characterizations with DFT calculations, we reveal that the abundant low valence V species accompanied anion vacancies on the surface of MXene have excellent oxygen activation capacity, which well explains its outstanding catalytic performance at low temperature. Moreover, the catalyst maintains its activity after 6 cycles of reuse, and is expected to act as a sustainable, efficient and stable AODS catalyst. [ABSTRACT FROM AUTHOR]

The photocatalytic oxidation of toluene to benzaldehyde has attracted wide attention due to its mild condition, low cost and green process. In general, the traditional semiconductor photocatalytic mechanism is an oxidation–reduction reaction between photogenerated carriers and reactants. Recently, the catalyst V6O13 shows the high photocatalytic activity because of the different photocatalytic mechanism from the oxidation–reduction reaction. The catalyst V6O13 and aliphatic alcohol would form V6O13–alkoxide, which could be excited by visible light to effectively activate the C–H bond of α–C. However, it is unknown whether the catalyst V6O13 could efficiently achieve photocatalytic oxidation of toluene and there is a similar photocatalytic mechanism for toluene by catalyst V6O13. In this work, the photocatalytic selective oxidation of toluene to benzaldehyde by V6O13 catalyst is systematically investigated by density functional theory. The results show that V6O13 catalyst can effectively activate toluene C(sp3)–H bond into benzyl with the activation energy is 14.2 kcal mol−1. The V6O13–toluene complex has stronger light absorption in the range from 200 to 800 nm than that of the individual V6O13 clusters. Furthermore, the barrier for the dehydration of C6H5CH2OOH and C6H5CHOHOH decreased from 49.0 to 35.0 kcal mol−1 and from 26.3 to 19.5 kcal mol−1, respectively. We trace these surprising results to the novel photocatalytic mechanism that the V6O13–toluene complex could be excited by light to effectively activate the toluene C(sp3)–H bond. Our work may provides new opportunities and challenges for photocatalytic field. [ABSTRACT FROM AUTHOR]

Vanadium phosphorous oxide (VPO) catalysts have been recognized as heterogeneous catalyst for selective oxidation of low-carbon alkanes i.e., n-butane toward maleic anhydride. This process has widely gained attention globally due to its highly selective and cost-effective process. Herein, we employed Cd0.2Zn0.8S as a support for the VPO catalyst and evaluated its n-butane catalytic performance. Compared to the unpromoted catalyst (Blank-VPO), a higher n-butane conversion and MA yield were successfully obtained from the promoted catalyst (Cd0.2Zn0.8S@VPO). Interestingly, it reduces the byproducts, i.e., CO2 and CO emission. Characterization methods such as TGA, XRD, EDS, SEM, FTIR, NH3-TPD, XPS, TEM, and Raman spectroscopy were used to characterize the Cd0.2Zn0.8S, VPO precursor and catalyst. [ABSTRACT FROM AUTHOR]

Vanadium oxide (VOx) thin films are promising materials, exhibiting electrical, optical, and mechanical properties highly tunable by processing and structure. This work uniquely applying atomic force microscopy (AFM) nanoindentation correlated with X-ray diffractometry and Raman spectroscopy structural analysis to investigate the intricate connections between VOx post-annealing, phase composition, and resulting nanoscale mechanical functionality. Utilizing an ultra-sharp diamond tip as a nanoscale indenter, indentation is performed on VOx films with systematic variations in structure – from mixed insulating oxides to VO2-dominated films. Analytical modeling enables extraction of hardness and elastic modulus with nanoscale resolution. Dramatic mechanical property variations are observed between compositions, with order-of-magnitude increases in hardness and elastic modulus for the VO2-rich films versus insulating oxides. Ion implantation further enhances nanomechanical performance through targeted defect engineering. Correlating indentation-derived trends with detailed structural and morphological characterization elucidates explicit structure-property relationships inaccessible by other techniques. The approach provides critical mechanics-driven insights into links between VOx synthesis, structure evolution, and property development. Broader implementation will accelerate processing optimization for electronics and advanced fundamental understanding of nanoscale structure-functionality relationships. [ABSTRACT FROM AUTHOR]

Rational designing of electrode materials having high surface area can accomplish the enhanced charge‐storing ability of the electrochemical energy storage devices. Therefore, the surface area of cobalt vanadium oxide (CVO) material is controlled by changing growth dynamics in successive ionic layer adsorption and reaction methods. Structural analysis confirms the formation of hydrous cobalt vanadium oxide nanoparticles (Co3V2O8⋅nH2O) thin film electrodes, and alteration in the surface area with change in growth dynamics is observed in Brunauer–Emmett–Teller analysis. The CVO1:1 thin film electrode prepared at optimal growth dynamics illustrates high specific capacitance (Cs) (capacity) of 793 F g−1 (396.7 C g−1) at 0.5 A g−1, respectively. Moreover, aqueous hybrid supercapacitor devices constructed using CVO1:1 as cathode exhibit high Cs of 133.5 F g−1 at 1.1 A g−1, specific energy (SE) of 47.7 Wh kg−1 with specific power (SP) of 0.90 kW kg−1. The solid‐state hybrid supercapacitor devices also offer high Cs of 102.9 F g−1 at 0.3 A g−1, SE of 36.6 Wh kg−1 at SP of 0.30 kW kg−1. In the SILAR approach, the dipping time plays a critical role in improving the surface area of the material and, consequently, electrochemical performance, as the current work amply indicates. [ABSTRACT FROM AUTHOR]

In this work, we prepared a pure α-Al2O3, α-Al2O3/CuO (AC) and α-Al2O3/V2O5 (AV) nanocomposite. The sol–gel method was used to prepare pure α-Al2O3, (AC) and (AV) samples at 1200 °C. Structural, electrical, and optical properties of the prepared samples were investigated using the X-ray diffraction (XRD), UV–Visible spectrophotometer, and conductivity meter, respectively. The XRD results confirmed the crystalline nature and the presence of the hexagonal structure of α-Al2O3, the rhombohedra structure of CuAlO2 and the tetragonal structure of V2O5. Moreover, the crystallite size of pure α-Al2O3 was 43.1 nm, while the crystallite size of α-Al2O3 in samples AC and AV nanocompsite was 24.05 nm and 34.84 nm respectively. The optical measurements showed that the band gap α-Al2O3 decreased significantly from 5.28 eV for pure to 3.7 and 3.4 eV to AC and AV respectively. The DC electrical conductivity (σd.c) values were measured for all prepared samples at room temperature. The electrical conductivity was 2.4 × 10–7 and 1.8 × 10–7 (Ω cm)−1 in AC and AV nanocompsite respectively, while ionic conductivity (σion) decreased from 3 × 10–10 in pure α-Al2O3 to 7 × 10–5 and 1 × 10–5 in AC and AV nanocompsite, respectively. The results showed an improvement in the structural, optical, and electrical properties, which may make these materials a candidate for use in many applications, such as photocatalytic, gas sensors, optoelectronics, microelectronics, semiconductor devices, ......etc. [ABSTRACT FROM AUTHOR]

Aqueous zinc‐ion batteries (AZIBs) are widely attractive by virtue of its high safety and low cost. However, their development for widespread applications is limited due to unstable cathode materials. Herein, a manganese vanadium oxide (Mn2V2O7/V2O3) (MnVO) composite is fabricated and can be utilized as a superior intercalated cathode for AZIBs. The extraction of Zn2+ from the MnVO composite causes the phase transition during the initial charge cycle to form electrochemically reversible MnV10O26·10H2O. The phase transformation modifies morphology and the as‐formed MnV10O26·10H2O phase acts as a Zn2+ host for the subsequent cycles, leading to excellent electrochemical performances. As a result, the electrode delivers a superior reversible capacity of 204 mA h g−1 at 1 A g−1 over 1000 cycles and is also sustainable over a long‐life span of 3000 cycles even at 10 A g−1. Additionally, the Zn/MnVO battery exhibits a high energy density of 256.31 Wh kg−1 at a power density of 410 W kg−1. The exceptional reversible capacity even at different current densities over a long‐life span makes them a promising candidate for fabricating the safe and reliable AZIBs. Also, the Zn2+ storage mechanism in MnVO composite cathode for rechargeable AZIBs is demonstrated. [ABSTRACT FROM AUTHOR]

In this work, we prepared a pure α-Al2O3, α-Al2O3/CuO (AC) and α-Al2O3/V2O5 (AV) nanocomposite. The sol–gel method was used to prepare pure α-Al2O3, (AC) and (AV) samples at 1200 °C. Structural, electrical, and optical properties of the prepared samples were investigated using the X-ray diffraction (XRD), UV–Visible spectrophotometer, and conductivity meter, respectively. The XRD results confirmed the crystalline nature and the presence of the hexagonal structure of α-Al2O3, the rhombohedra structure of CuAlO2 and the tetragonal structure of V2O5. Moreover, the crystallite size of pure α-Al2O3 was 43.1 nm, while the crystallite size of α-Al2O3 in samples AC and AV nanocompsite was 24.05 nm and 34.84 nm respectively. The optical measurements showed that the band gap α-Al2O3 decreased significantly from 5.28 eV for pure to 3.7 and 3.4 eV to AC and AV respectively. The DC electrical conductivity (σd.c) values were measured for all prepared samples at room temperature. The electrical conductivity was 2.4 × 10–7 and 1.8 × 10–7 (Ω cm)−1 in AC and AV nanocompsite respectively, while ionic conductivity (σion) decreased from 3 × 10–10 in pure α-Al2O3 to 7 × 10–5 and 1 × 10–5 in AC and AV nanocompsite, respectively. The results showed an improvement in the structural, optical, and electrical properties, which may make these materials a candidate for use in many applications, such as photocatalytic, gas sensors, optoelectronics, microelectronics, semiconductor devices, ......etc. [ABSTRACT FROM AUTHOR]

We facilely prepared a solid-state heterojunction photocatalyst in which silver vanadium oxide (Ag2V4O11) and zinc rhodium oxide (ZnRh2O4) as oxygen and hydrogen evolution photocatalysts, respectively, were directly connected to generate Ag2V4O11/ZnRh2O4. Ag2V4O11/ZnRh2O4 photocatalyzed overall pure-water splitting without any electron mediator under irradiation with near-infrared light at wavelengths of up to 910 nm. The key points are that the conduction bottom potential of Ag2V4O11 is almost the same as the valence band top potential of ZnRh2O4, and that the bandgaps of Ag2V4O11 and ZnRh2O4 are 1.4 and 1.2 eV, respectively. [ABSTRACT FROM AUTHOR]

Semiconducting nanomaterials based heterogeneous photocatalysis represent a low-cost, versatile technique for environmental remediation, including pollution mitigation, energy management and other environmental aspects. Herein, we demonstrate the syntheses of various heterogeneous photocatalysts based on highly reduced graphene oxide (HRG) and vanadium oxide (VOx)-based nanocomposites (HRG–VOx). Different shapes (rod, sheet and urchin forms) of VOx nanoparticles were successfully fabricated on the surface of HRG under solvo-/hydrothermal conditions by varying the amount of water and ethanol. The high concentration of water in the mixture resulted in the formation of rod-shaped VOx nanoparticles, whereas increasing the amount of ethanol led to the production of VOx sheets. The solvothermal condition using pure ethanol as solvent produced VOx nano-urchins on the surface of HRG. The as-prepared hybrid materials were characterized using various spectroscopic and microscopic techniques, including X-ray diffraction, UV–vis, FTIR, SEM and TEM analyses. The photocatalytic activities of different HRG–VOx nanocomposites were investigated for the photodegradation of methylene blue (MB) and methyl orange (MO). The experimental data revealed that all HRG–VOx composite-based photocatalysts demonstrated excellent performance toward the photocatalytic degradation of the organic dyes. Among all photocatalysts studied, the HRG–VOx nanocomposite consisting of urchin-shaped VOx nanoparticles (HRG–VOx-U) demonstrated superior photocatalytic properties towards the degradation of dyes. [ABSTRACT FROM AUTHOR]

The introduction of metal sites into molecular metal oxides, so-called polyoxometalates, is key for tuning their structure and reactivity. The complex mechanisms which govern metal-functionalization of polyoxometalates are still poorly understood. Here, we report a coupled set of light-dependent and light-independent reaction equilibria controlling the mono- and di-metal-functionalization of a prototype molecular vanadium oxide cluster. Comprehensive mechanistic analyses show that coordination of a Mg2+ ion to the species {(NMe2H2)2[VV12O32Cl]}3- results in formation of the mono-functionalized {(NMe2H2)[(MgCl)VV12O32Cl]}3- with simultaneous release of a NMe2H2+ placeholder cation. Irradiation of this species with visible light results in one-electron reduction of the vanadate, exchange of the second NMe2H2+ with Mg2+, and formation/crystallization of the di-metal-functionalized [(MgCl)2VIVVV11O32Cl]4-. Mechanistic studies show how stimuli such as light or competing cations affect the coupled equilibria. Transfer of this synthetic concept to other metal cations is also demonstrated, highlighting the versatility of the approach. The introduction of metal sites into polyoxometalates is key for tuning their structure and reactivity but the complex mechanisms which govern metal functionalization of polyoxometalates are still poorly understood. Here, the authors report a coupled set of light-dependent and light-independent reaction equilibria controlling the mono- and di- metal-functionalization of a prototype molecular vanadium oxide cluster [ABSTRACT FROM AUTHOR]

Vanadium oxides have been extensively studied once vanadium oxidation states provide unique characteristics, allowing applications in several areas, such as light-emitting devices and photocatalysts. The solid-state reaction is the oldest route for synthesizing ceramic compounds; however, it includes a lack of homogeneity and purity in the final material. In contrast, the Pechini method enables excellent particle size and morphology control, together with high-purity materials, at lower temperatures and reaction times. Although synthesis strongly influences the material's applicability, few studies have compared these methods experimentally. The present work expects to contribute to understanding the differences between solid-state reaction and Pechini routes in the obtention of CaV2O7 and how it impacts the final characteristics of the material. The synthesis was carried out using the solid-state method and modified Pechini in a temperature range of 650–850 °C. The powders possess a particle distribution as a function of temperature. The material shows an absorbing performance of about 500 nm, with a band gap of around 3 eV, slightly higher for the solid-state reaction route, as it is closely related to the size and purity of the particles. In summary, the results suggest that the solid-state reaction requires a higher temperature to obtain a higher purity material, while the Pechini method provides the same purity at all temperatures applied, together with a more homogeneous morphology, which shows to be a promising photocatalyst material capable of decolorizing 40% of a methylene blue solution in 120 min where it can play an important role for wastewater treatments. [ABSTRACT FROM AUTHOR]

Low reflectivity is of great significance to photoelectric devices, optical displays, solar cells, photocatalysis and other fields. In this paper, vanadium oxide is deposited on pattern SiO2 via atomic layer deposition and then annealed to characterize and analyze the anti-reflection effect. Scanning electron microscope (SEM) images indicate that the as-deposited VOx film has the advantages of uniformity and controllability. After annealing treatment, the VO2@pattern SiO2 has fewer crevices compared with VO2 on the accompanied planar SiO2 substrate. Raman results show that there is tiny homogeneous stress in the VO2 deposited on pattern SiO2, which dilutes the shrinkage behavior of the crystallization process. The optical reflection spectra indicate that the as-deposited VOx@pattern SiO2 has an anti-reflection effect due to the combined mechanism of the trapping effect and the effective medium theory. After annealing treatment, the weighted average reflectance diminished to 1.46% in the visible near-infrared wavelength range of 650–1355 nm, in which the absolute reflectance is less than 2%. Due to the multiple scattering effect caused by the tiny cracks generated through annealing, the anti-reflection effect of VO2@pattern SiO2 is superior to that of VOx@pattern SiO2. The ultra-low reflection frequency domain amounts to 705 nm, and the lowest absolute reflectance emerges at 1000 nm with an astonishing value of 0.86%. The prepared anti-reflective materials have significant application prospects in the field of intelligent optoelectronic devices due to the controllability of atomic layer deposition (ALD) and phase transition characteristics of VO2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrodeoxygenation of phenol in gas phase over Pd-VO x /SiO 2 catalysts. • Pd/SiO 2 promotes hydrogenation pathways whereas VO x addition favors deoxygenation. • Deoxygenation depends on the contact between V3+ and V4+ cations and metal particle. • Pd-VO x interface is responsible for the activation of the C = O bond. This work investigates the effect of vanadia species on the performance of Pd/VO x /SiO 2 catalysts containing different vanadia loadings for HDO of phenol in the gas phase. in situ XANES experiments reveal the presence of a mixture of V 2 O 4 and V 4 O 7 species for all catalysts after reduction at 573 K. In situ XRD and XANES demonstrate that Pd particles and VO x species are in close contact, which is likely due to the presence of polymerized vanadate species, regardless of vanadia content, as shown by UV–Vis spectroscopy. This close contact promotes the selective hydrogenation of the C = O bond or the cleavage of the C-O bond, producing benzene. The strong interaction between the oxygen of the tautomer intermediate molecule and the oxygen vacancies associated with the presence of V3+ and V4+ cations is responsible for the deoxygenation activity of Pd/VO x /SiO 2 catalysts. [ABSTRACT FROM AUTHOR]

Nanoscaled-VPO (vanadium phosphate oxide) catalysts have been prepared on an alumina support with the objective of obtaining crystallites of the active phase with a high surface-to-volume ratio. Since the catalysed reaction occurs at the surface, these nanoscaled catalysts allows studying surface species transformations with a minimized signal from the bulk dominion. The chemical environment and oxidation state of these species has been determined by a combination of NMR, ESR and XANES spectroscopies. The results have allowed to optimize V + P coverage and V/P molar ratio to minimize the concentration of isolated vanadium oxide species and maximize V4+ concentration. The distribution of phosphorus islands ordered and significantly distorted of tetra- and penta-coordinated aluminium sites of the catalytic support, thus shaping the catalytic material to an optimal structure for the desired partial oxidation reaction. [ABSTRACT FROM AUTHOR]

Hierarchical Amorphous Vanadium Oxide and Carbon Nanotubes Microspheres with Strong Interface Interaction for Superior Performance Aqueous Zinc-ion Batteries. [Display omitted] Aqueous zinc-ion batteries have attracted more and more attention due to their safety, environmental benignity and high theoretical capacity. However, the lack of appropriate cathode materials with high capacity and long cycle life have become an obstacle to the development of aqueous zinc-ion batteries. Herein, the hierarchical amorphous vanadium oxide and carbon nanotubes (a-V 2 O 5 @CNTs) microspheres with strong interface interaction were successfully prepared by combing facile spray drying technique with annealing treatment. Benefiting from the a-V 2 O 5 amorphous characters, CNTs framework high conductivity and hierarchical microspheres with strong interface interaction, the a-V 2 O 5 @CNTs exhibited abundant active sites, fast reaction kinetics as well as eminent structure stability. As a promising electrode material, the a-V 2 O 5 @CNTs displayed high specific capacity (480 mAh g−1 at 0.5 A g−1), good rate capability and long-term stability under high current density (158 mAh g−1 at 30 A g−1 over 1000 cycles). Meanwhile, the corresponding mechanism was further illustrated through different characterizations. Furthermore, the as-assembled flexible pouch battery based on the a-V 2 O 5 @CNTs delivered outstanding flexibility and feasibility. Hence, this work provides a new idea for developing high performance cathode materials of aqueous zinc-ion batteries. [ABSTRACT FROM AUTHOR]

Vanadium oxides have been extensively studied once vanadium oxidation states provide unique characteristics, allowing applications in several areas, such as light-emitting devices and photocatalysts. The solid-state reaction is the oldest route for synthesizing ceramic compounds; however, it includes a lack of homogeneity and purity in the final material. In contrast, the Pechini method enables excellent particle size and morphology control, together with high-purity materials, at lower temperatures and reaction times. Although synthesis strongly influences the material's applicability, few studies have compared these methods experimentally. The present work expects to contribute to understanding the differences between solid-state reaction and Pechini routes in the obtention of CaV2O7 and how it impacts the final characteristics of the material. The synthesis was carried out using the solid-state method and modified Pechini in a temperature range of 650–850 °C. The powders possess a particle distribution as a function of temperature. The material shows an absorbing performance of about 500 nm, with a band gap of around 3 eV, slightly higher for the solid-state reaction route, as it is closely related to the size and purity of the particles. In summary, the results suggest that the solid-state reaction requires a higher temperature to obtain a higher purity material, while the Pechini method provides the same purity at all temperatures applied, together with a more homogeneous morphology, which shows to be a promising photocatalyst material capable of decolorizing 40% of a methylene blue solution in 120 min where it can play an important role for wastewater treatments. [ABSTRACT FROM AUTHOR]

The composition of 75V2O5–(25-x) MgO–xLi2O (x = 0, 1.5, 3.0, 4.5, and 6.0) is synthesized by the melt quenching method. The effects of Li2O on devitrification, physical, thermal, structural, and conducting properties of the as-quenched samples are analyzed utilizing various experimental techniques. X-ray diffraction and differential thermal analysis confirmed the formation of phase-separated glasses up to 3.0 mol. % of Li2O. Above this concentration of Li2O, the samples are glass ceramic. With an increase in the concentration of Li2O, the density increases in all the samples. The Raman spectra demonstrate that as the concentration of Li2O increases, there is a transition of VO5 units into different structural units of vanadium oxide. The highest conductivity is observed for the composition with x = 4.5, i.e., 10−4 S/cm at 250 °C. The activation energy indicated that the present samples could be mixed conductors in nature. These samples can be used as cathode materials in energy storage devices due to their mixed conduction with an appropriate conductivity at 250 °C. [ABSTRACT FROM AUTHOR]

Due to metal–insulator transitions occurring in those compounds, materials and devices based on vanadium (III) and (IV) oxides draw increasing scientific attention. In this paper, we observed the transitions in both oxides using contemporary laboratory equipment. Changes in the crystallographic structure were precisely investigated as a function of the temperature with a step of 2 °C. Thermal effects during transitions were observed using differential scanning calorimetry. The DC conductivity of the materials was measured quasi-continuously as a function of the temperature. All the experiments were consistent and showed considerable hysteresis of the metal–insulator transition in both vanadium oxides. [ABSTRACT FROM AUTHOR]

Metal–oxide–metal devices based on amorphous VOx are shown to exhibit one of two distinct negative differential resistance (NDR) characteristics depending on the maximum current employed for electroforming. For low compliance currents they exhibit a smooth S-type characteristic and have a temperature-dependent device resistance characterized by an activation energy of 0.25 eV, consistent with conduction in polycrystalline VO2, while for high compliance currents they exhibit an abrupt snap-back characteristic and a resistance characterized by an activation energy of 0.025 eV, consistent with conduction in oxygen deficient VOx. In both cases, the temperature dependence of the switching voltage implies that the conductivity change is due to the insulator–metal transition in VO2. From this analysis, it is concluded that electroforming at low currents creates a conductive filament comprised largely of polycrystalline VO2, while electroforming at high currents creates a composite structure comprised of VO2 and a conductive halo of oxygen deficient VOx. The effect of electroforming on the NDR mode is then explained with reference to a lumped element model of filamentary conduction that includes the effect of a parallel resistance created by the halo. These results provide new insight into the NDR response of vanadium-oxide-based devices and a basis for designing devices with specific characteristics. [ABSTRACT FROM AUTHOR]

The influence of different solvents, including aqueous and nonaqueous types, on the physicochemical properties of V2O5 nanostructures was thoroughly investigated. Various characterization techniques, such as XRD, XPS, FTIR, Raman spectroscopy, UV-vis DRS, SEM, TEM, and BET, were employed to analyze the obtained materials. Additionally, the adsorption properties of the synthesized V2O5 nanostructures for methylene blue were examined, and kinetic parameters of adsorption were calculated. The results demonstrate that the morphology of the obtained crystals can be finely controlled by manipulating water concentration in the solution, showcasing its profound impact on both the structural characteristics and adsorption properties of the nanostructures. Furthermore, the structural changes of the resulting V2O5 material induced by solvents show strong impacts on its photocatalytic properties, making it a promising photocatalyst.

Two different Mott insulator wires, vanadium dioxide and vanadium sesquioxide, were prepared on the piezoelectric LiNbO3 substrates. Coupling of acoustic waves propagating in LiNbO3 with free carriers in vanadium oxide gives rise to the acoustoelectric effect that manifests itself as the generation of direct electric current by the acoustic wave. According to a phenomenological model, the value of the effect strongly depends on the wires conductivity, which, for the vanadium-oxide films, changes by a few orders of magnitude. We demonstrated that this yields a significant enhancement of the direct current (DC) current generated in the wires at the metal–insulator transition temperatures. The sign of the generated DC voltage is different for excitations by surface and bulk acoustic wave modes, which may happen due to reverse wave propagation at the substrate surface. For each resonance mode, polarities of the generated DC signal are the same in both wires, despite the signs of charge carriers being different for these materials. It was shown that two complementary techniques (acoustoelectric and Hall effect measurements) yield opposite signs of charge carriers in VO2. [ABSTRACT FROM AUTHOR]

High-temperature superconductors such as REBa2Cu3O7 − δ (REBCO, RE = rare earth) enable high-current cables and high-field magnets. By removing the turn-to-turn insulation in a magnet application, recent experiments demonstrated that REBCO magnets can self-protect against catastrophic damage during a superconducting-to-normal transition (quench), i.e., when the stored magnetic energy rapidly converts to heat. The current can bypass the hot spot during a quench, thereby reducing the localized heat dissipation. The removal of the insulation between turns, however, leads to excessive eddy currents during current ramping, thereby forcing a much-prolonged magnet charging time. To address this issue, we investigate vanadium oxide (VOx) coatings as a temperature-dependent self-switching medium that automatically manages current sharing. VOx coatings (with 1.70 ≤ × ≤ to 2.07) were deposited by reactive cathodic arc deposition, initially on insulating glass to determine the electrical properties, and later on commercial REBCO tapes. The coatings are x-ray amorphous but with a short-range crystalline ordering according to Raman spectrometry. The resistivity of VOx decreased by at least three orders of magnitude when the temperature increased from 80 to 300 K. The coating process is compatible with commercial REBCO tapes as evidenced by the negligible change in the critical current caused by the coating process. The results from current sharing experiments and circuit analysis suggest that the VOx coating can effectively self-regulate current sharing in REBCO magnets, suppress excessive eddy currents, and enable self-protection during quenches. [ABSTRACT FROM AUTHOR]

We prepared a solid-state Z-scheme photocatalyst in which zinc rhodium oxide (ZnRh2O4) and bismuth vanadium oxide (Bi4V2O11) that served as hydrogen (H2) and oxygen (O2) evolution photocatalysts, respectively, were connected with gold (Au) nanoparticles. The Au nanoparticles were prepared by sputtering in an ionic liquid, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide, to generate Au/ZnRh2O4/Au/Bi4V2O11 with various amounts of Au in the 12 mol. %–29 mol. % range (vs 1.0 mol ZnRh2O4 + 0.2 mol Bi4V2O11). Au/ZnRh2O4/Au/Bi4V2O11 photocatalyzed overall pure-water splitting under irradiation with red light at a wavelength of 700 nm, and the dependence of the amounts of Au on the apparent quantum efficiency tended to increase in the measurement range. [ABSTRACT FROM AUTHOR]

In this work, ambient pressure x-ray photoelectron spectroscopy (APXPS) is used to study the initial stages of water adsorption on vanadium oxide surfaces. V 2p, O 1s, C 1s, and valence band XPS spectra were collected as a function of relative humidity in a series of isotherm and isobar experiments. Experiments were carried out on two VO2 thin films on TiO2 (100) substrates, prepared with different surface cleaning procedures. Hydroxyl and molecular water surface species were identified, with up to 0.5 ML hydroxide present at the minimum relative humidity, and a consistent molecular water adsorption onset occurring around 0.01% relative humidity. The work function was found to increase with increasing relative humidity, suggesting that surface water and hydroxyl species are oriented with the hydrogen atoms directed away from the surface. Changes in the valence band were also observed as a function of relative humidity. The results were similar to those observed in APXPS experiments on other transition metal oxide surfaces, suggesting that H2O–OH and H2O–H2O surface complex formation plays an important role in the oxide wetting process and water dissociation. Compared to polycrystalline vanadium metal, these vanadium oxide films generate less hydroxide and appear to be more favorable for molecular water adsorption. [ABSTRACT FROM AUTHOR]

Abstract Active thermal radiation control of an object requires adaptive and flexible strategies to cope with emissivity engineering and its temperature dependence. On the other hand, the concept of digital coding allows a high degree of freedom in manipulating the interacting physical quantities based on local discretized features. Learning from this idea, this study put forward the manipulation of spatial infrared emission based on tungsten (W)‐doped VO2 films toward thermal coding. Here, 1‐bit coding worksheets created by low‐emissivity, that is, code ‘0′, and high‐emissivity, that is, code ‘1′, shift with materials metal‐insulator phase transition to encode emissive information in the temperature domain. It is shown experimentally that this concept has marked implications on thermal radiation control at Mid‐infrared, among which are as follows: digital anti‐counterfeiting by in‐plane spatial coding of a group of VO2 thin films with various W‐doping density and infrared camouflage by out‐of‐plane spatial coding of them. With a W‐doping gradient of 0%, 0.8%, and 1.7%, the three‐phase transition points in the temperature domain, that is, 72, 63, and 45 °C, give a remarkable modulation range of 27 °C. These phenomena pave the way for new classes of emissivity engineering for more accurate, flexible, and adaptive thermal radiation control.

Molecular metal oxides, so‐called polyoxometalates (POMs), have shown outstanding performance as catalysts and lately attracted interest as materials in energy conversion and storage systems due to their capability of storing and exchanging multiple electrons. Here, we report the first example of redox‐driven reversible electrodeposition of molecular vanadium oxide clusters, leading to the formation of thin films. The detailed investigation of the deposition mechanism reveals that the reversibility is dependent on the reduction potential. Correlating electrochemical quartz microbalance studies with X‐ray photoelectron spectroscopy (XPS) data gave insight into the redox chemistry and oxidation states of vanadium in the deposited films in dependence on the potential window. A multi‐electron reduction of the polyoxovanadate cluster, which facilitates the potassium (K+) cation‐assisted reversible formation of potassium vanadium oxide thin films was confirmed. At anodic potentials, re‐oxidation of the polyoxovanadate and complete stripping of the thin film is observed for films deposited at potentials more positive than −500 mV vs. Ag/Ag+, while electrodeposition at more negative cathodic potential reduces the electrochemical reversibility of the process and increases the stripping overpotential. As proof of principle, we demonstrate the electrochemical performance of the deposited films for potential use in potassium‐ion batteries. [ABSTRACT FROM AUTHOR]

Layered V10O24·nH2O with a large interlayer spacing of 14 Å is hydrothermally synthesized and used as a cathode for potassium-ion batteries. It exhibits a capacity of 110 mA h g−1 with a capacity retention of 99.2% over 700 cycles. Its storage mechanism is identified as pseudo-capacitive intercalation. [ABSTRACT FROM AUTHOR]

The development of highly effective dressing materials for human injuries that meet the complex requirements for clinical examination is still a challenge. In this regard, different biomaterials could be examined for wound dressing targets. Among these materials, polycaprolactone (PCL) is high biocompatible polymeric substance and has been used for numerous pharmaceutical applications. Furthermore, targeting antibacterial behavior could be done by merging additional nanoparticles such as copper oxide (CuO) and vanadium Oxide (V 2 O 5). The scaffolds could be fabricated using the cast method, which is one of the most simple and facile methods. The morphological features and the surface roughness of the fabricated could be examined using X-ray diffraction, Raman spectroscopy, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) tests. The contact angle plays a significant role in studying the wettability of the scaffolds and the hydrophilic or hydrophobic behavior of the composed films. Besides the antibacterial behavior to evaluate the effectiveness of these scaffolds to protect the injury until the healing. The cell viability against human normal cells to examine the biocompatibility of the proposed compositions. In this regard, the topographical images show a smooth surface with random pores that have diameters in the range of 0.5–1.5 μm for pure PCL while, the porosity decreased with the addition of ginger and V 2 O 5. The blend of CuO/V 2 O 5 /ginger@ PCL represents a noticeable increase in porosity with a diameter between 0.5 and 3 μm. The contact angles were recorded respectively at 55.02°, 54.12°, 53.89°, and 53.71° which refer to the tendency of the scaffolds to the hydrophilic behavior. In addition, the anti-bacterial activity of CuO/V 2 O 5 /ginger@PCL was represented with the diameter of the inhibition zone equal to 17.6±1.2 mm for E. coli and 12.3±1.2 mm for S. aureus. [ABSTRACT FROM AUTHOR]

Highlights: The over-reduction from Nb5+ to Nb3+ in the lithiation process have been demonstrated to be the critical reason for the capacity decay of Nb2O5 for the first time. A novel competitive redox strategy has been proposed to suppress the over-reduction of Nb5+ to Nb3+, which can be achieved by the incorporation of vanadium to form a new rutile VNbO4 anode. The performance of VNbO4 anode designed in this study stands among the best in cycle stability. Niobium pentoxide (Nb2O5) anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety. However, Nb2O5 anode suffers poor cycle stability even after modified and the unrevealed mechanisms have restricted the practical applications. Herein, the over-reduction of Nb5+ has been demonstrated to be the critical reason for the capacity loss for the first time. Besides, an effective competitive redox strategy has been developed to solve the rapid capacity decay of Nb2O5, which can be achieved by the incorporation of vanadium to form a new rutile VNbO4 anode. The highly reversible V3+/V2+ redox couple in VNbO4 can effectively inhibit the over-reduction of Nb5+. Besides, the electron migration from V3+ to Nb5+ can greatly increase the intrinsic electronic conductivity for VNbO4. As a result, VNbO4 anode delivers a high capacity of 206.1 mAh g−1 at 0.1 A g−1, as well as remarkable cycle performance with a retention of 93.4% after 2000 cycles at 1.0 A g−1. In addition, the assembled lithium-ion capacitor demonstrates a high energy density of 44 Wh kg−1 at 5.8 kW kg−1. In summary, our work provides a new insight into the design of ultra-fast and durable anodes. [ABSTRACT FROM AUTHOR]

Inevitable dissolution in aqueous electrolytes, intrinsically low electrical conductivity, and sluggish reaction kinetics have significantly hampered the zinc storage performance of vanadium oxide‐based cathode materials. Herein, core–shell N‐doped carbon‐encapsulated amorphous vanadium oxide arrays, prepared via a one‐step nitridation process followed by in situ electrochemical induction, as a highly stable and efficient cathode material for aqueous zinc‐ion batteries (AZIBs) are reported. In this design, the amorphous vanadium oxide core provides unobstructed ions diffusion routes and abundant active sites, while the N‐doped carbon shell can ensure efficient electron transfer and greatly stabilize the vanadium oxide core. The assembled AZIBs exhibit remarkable discharge capacity (0.92 mAh cm−2 at 0.5 mA cm−2), superior rate capability (0.51 mAh cm−2 at 20 mA cm−2), and ultra‐long cycling stability (≈100% capacity retention after 500 cycles at 0.5 mA cm−2 and 97% capacity retention after 10 000 cycles at 20 mA cm−2). The working mechanism is further validated by in situ X‐ray diffraction combined with ex situ tests. Moreover, the fabricated cathode is highly flexible, and the assembled quasi‐solid‐state AZIBs present stable electrochemical performance under large deformations. This work offers insights into the development of high‐performance amorphous vanadium oxide‐based cathodes for AZIBs. [ABSTRACT FROM AUTHOR]