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The oxidative desulphurization (ODS) has become mainly popular by rapid catalytic oxidation of dibenzothiophene (DBT) relied on efficient heterogeneous catalyst. V-based catalytic active species were regarded as the potential option in the activity-preferred ODS systems. Herein, we reported the re-dispersion of vanadium oxide (VOx) on the mesoporous silica modified with manganese oxide (Mn3O4) through one progressive insertion approach of metal oxides in the silica. Impressively, mesopore-encaged vanadium-manganese oxides in the silica (VMn-MS) as the admirable output of excellent ODS catalyst was demonstrated compared to other monometal-modified counterparts and one-pot implanted one. The characterization results revealed the post-implanted VOx species not only deposited around the pre-covered Mn3O4 on the mesoporous surface but also inserted the surface layer of Mn3O4 inducing the amorphous evolution of aggregated Mn3O4 and the reconstruction of final active sites. This integrated approach made the reconstructed active species afford more exposed catalytic sites and the tailored surface redox cycles owing to the electronic communication of V-Mn. The catalytic results demonstrated the excellent catalytic desulphurization efficiency (∼100%) during 60 min at 80 °C, which made the sulphur content reduce to 6 mg·L-1, remarkably superior to other comparative samples. The outstanding catalytic performance of VMn-MS catalyst can be ascribed to the synergistic effect of V-Mn dual metals rendering two different reaction pathways, which includes free-radical reaction and ring-forming reaction, where Mn site acted as active center triggering reactive free radicals which could be further optimized by surrounded V sites around Mn sites to promote the ODS process.

Zinc-ion batteries (ZIBs), in particular quasi-solid-state ZIBs, occupy a crucial position in the field of energy storage devices owing to the superiorities of abundant zinc reserve, low cost, high safety and high theoretical capacity of zinc anode. However, as divalent Zn2+ ions experience strong electrostatic interactions when intercalating into the cathode materials, which poses challenges to the structural stability and higher demand in Zn2+ ions diffusion kinetics of the cathode materials. Here, a microwave-assisted hydrothermal method is adopted to prepare pre-potassiated hydrated vanadium pentoxide (K0.52V2O5•0.29H2O, abbreviated as KHVO) cathode material, in which the potassium ions pre-inserted into the interlayers can act as “pillars” to stabilize the lamellar structure, and crystal water can act as “lubricant” to improve the diffusion efficiency of Zn2+ ions. Consequently, the KHVO displays high electrochemical properties with high capacity (∼ 300 mAh/g), superior rate capability (69 mAh/g at 5 A/g) and ultralong cycling performance (>1500 cycles at 2 A/g) in quasi-solid-state ZIBs. These superior Zn storage properties result from the large diffusion coefficient and highly stable and reversible Zn2+ (de)intercalation reaction of KHVO.

In recent years, especially when there is increasing concern about the safety issue of lithium-ion batteries (LIBs), aqueous Zn-ion batteries (ZIBs) have been getting a lot of attention because of their cost-effectiveness, materials abundance, high safety, and ecological friendliness. Their working voltage and specific capacity are mainly determined by their cathode materials. Vanadium oxides are promising cathode materials for aqueous ZIBs owing to their low cost, abundant resources, and multivalence. However, vanadium oxide cathodes still suffer from unsatisfactory capacity, poor stability, and low electrical conductivity. In this work, cascading V2O3/nitrogen doped carbon (V2O3/NC) hybrid nanosheets are prepared for high-performance aqueous ZIBs by pyrolyzing pentyl viologen dibromide (PV) intercalated V2O5 nanosheets. The unique structure features of V2O3/NC nanosheets, including thin sheet-like morphology, small crystalline V2O3 nanoparticles, and conductive NC layers, endow V2O3/NC with superior performance compared to most of the reported vanadium oxide cathode materials for aqueous ZIBs. The V2O3/NC cathode exhibits the discharge capacity of 405 mAh/g at 0.5 A/g, excellent rate capability (159 mAh/g at 20 A/g), and outstanding cycling stability with 90% capacity retention over 4000 cycles at 20 A/g.

Current report is based on the synthesis of Gd+3 doped V2O5 nanostructures (GVO) along with fabrication of GVO/MXene binary nanocomposite. As synthesized GVO and GVO/MXene were characterized by XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), EDX (Energy dispersive X-ray), BET (Brunauer Emmett Teller technique) and UV–Visible spectroscopy. Diffraction and elemental analysis confirmed the substitution of Gd+3 ions in VO layers. Orthorhombic phase of VO was observed in both GVO and GVO/MXene samples with crystallite size range of 17.02–17.51 nm. FESEM analysis indicated asymmetrical VO particles and sheets distributed on MXene layers, giving out a sponge like appearance. Surface area of GVO and GVO/MXene was enhanced to 20.46 and 23.69 nm, respectively. Effect of Gd+3 contents was significant on optical properties, which reduced the band gap energy of VO to 2.33 eV. The photocatalytic performance of prepared samples was analysed by the degradation of Methylene blue (MB) under direct sunlight. Gd+3 ion doping was found useful to enhance degradation of MB up to ∼71%. Among all samples, GVO/MXene showed maximum degradation (∼92%) within 120 min. Meanwhile, GVO/MXene showed good recyclability for successive five cycles. In addition, GVO and GVO/MXene were effective antibacterial agents against Gram positive (S. aureus) and Gram negative (P. vulgaris) strains of bacteria. The results suggested that the GVO and GVO/MXene could serve as potential candidates for large scale treatment of organic pollutants and pathogens.

The dopant-related issues are amongst the major performance bottleneck in crystalline silicon solar cells that can be alleviated via implementation of dopant-free layers. This work presents the implementation of tungsten oxide (WOx) and titanium oxide (TiOx) as hole- and electron-selective films for heterostructure solar cell design whereby n-type Si wafer has been passivated with ultrathin silicon oxide (SiO2) layer. Several designs have been investigated including passivated hydrogenated amorphous silicon (i-a-Si:H) and characterized by evaluating work function, electron affinity, interfacial charge, and layer thickness. The high work function of WOx induces significant upward band bending to permit holes transportation towards anode, whereas, low electron-affinity for TiOx reduces the barrier against electrons at the cathode. Smaller band offsets have been observed against minority carriers for devices that employ passivated i-a-Si:H film. However, incorporating SiO2 significantly improves the energy barrier height against minority carriers that leads to an enhancement in electric field along with reduction in recombination. The best-performance device with an optimum SiO2 thickness of 1 nm numerically validated V-oc of 751 mV, J(sc) 40.2 mA/cm(2), FF 79.7%, and rl of 24.06%. A comparative analysis with hole-selective vanadium oxide (V2Ox) demonstrated eta of 21.73% limited by the low work function of V2Ox. (C) 2021 Elsevier Ltd. All rights reserved.

Mixed metal oxides gain potential interest as the conversion of energy and electrode material for storage. Some notable attributes like supremacy on power and energy density, long cyclic stability, and quick reaction to form supercapacitors are essential, like energy storage devices. Contemplating those views of supercapacitors, in the present investigation, the new manganese vanadium oxide has been synthesized by microwave synthesis and followed by a hydrothermal process with an open-faced hollow sphere-like structure. It contains a high surface that gives more electrochemically active sites for energy storage and multivalence response. The sample has been characterized using X-ray diffraction and Raman spectroscopy for confirming phase, characterized by field emission scanning electron microscopy for morphological features. Electrochemical analyses of as-synthesized samples are investigated thoroughly to anticipate the view of that system's approach in an energy storage device. The specific capacitance is analyzed to be 340F/g in 0.5A/g current density and 1900F/g at 2 mV/s scan rate. This mixed metal oxide depicts higher stability and up to 1,000 cycles, which is 91% at a current density of 10A/g. It displays a high energy density of 13Wh/kg at the power density of 3500 W/kg in the current density of 8A/g. The potential value-specific capacitance, rated capacity, and long cycle stability make it a prominent candidate to fulfill the urge to engineering new advanced materials for energy storage applications.

Power plants, gas power turbines and chemical based plants face a very big issue of accelerated type of corrosion i.e hot corrosion, because of which the lifespan of metal decreased to large extent. In the present investigation, S-304 steel was taken which is commonly used in thermal power plants for inspection of accelerated corrosion i.e hot corrosion and high temp. oxidation behaviour. Alumina plus 13% titanium(Al2O3 + 13%TiO2), Alumina plus 3% titanium (Al2O3 + 3%TiO2) , Alumina(Al2O3)powder was applied on the boiler steel samples by using plasma spraying process. The uncoated and coated samples were exposed for 50 cycles to cyclic high temperature oxidation in air at 900 °C and hot corrosion in molten salt conditions of sodium sulphate and vanadium oxide (Na2SO4 – 60% V2O5) at 900 °C. In Oxidation study, with weight gain of 1.86% the upmost resistance against oxidation was exhibited by Alumina plus 13% titanium coated(Al2O3 + 13%TiO2) followed by Alumina plus 3% titanium coated (Al2O3 + 3%TiO2) with weight gain of 2.36% and by 2.92% by Alumina coated(Al2O3). The least resistance was shown by bare S-304 with weight gain of 3.91%.In investigation of hot corrosion, the weight gain percentages of Alumina plus 13% titanium coated(Al2O3 + 13%TiO2) is 2.46%, Alumina plus 3% titanium coated (Al2O3 + 3%TiO2) coated is 2.92%, Alumina coated(Al2O3) is 3.77% and for uncoated its 4.67%. The outcomes obtained for protection against oxidation and hot corrosion is: plus 13% titanium (Al2O3 + 13%TiO2) > Alumina plus 3% titanium (Al2O3 + 3%TiO2) coated > Alumina(Al2O3) > uncoated S-304 boiler steel.

A bifunctional ternary manganese oxide/vanadium oxide/reduced graphene oxide (MnO2/V2O5/rGO) was developed for asymmetric electrochromic supercapacitor (EC-SC) application. The elemental mapping revealed uniformly distributed MnO2, V2O5 and rGO, depicting homogenous synthesis of the hybrid composite. The phase composition, vibration modes and valance state of the ternary composite were analyzed via X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis, respectively. Interestingly, the as-prepared MnO2/V2O5/rGO composite disclosed tremendous Csp of 1403.5 F/g, which was higher compared to MnO2/V2O5 (801.1 F/g), V2O5 (613.1 F/g), MnO2 (126.7 F/g) and rGO (60.7 F/g). MnO2/V2O5/rGO that appeared in dark green switched its visual color to orange at the charged state, confirming the electrochromic property. The bifunctional manganese oxide/vanadium oxide/reduced graphene oxide//copper-based metal-organic framework/reduced graphene oxide (MnO2/V2O5/rGO//MrGO) asymmetrical EC-SC device revealed outstanding cycling stability (90.3% charge retention over 5000 cycles), tremendous specific capacitance (652.7 F/g) and maximum specific energy (60.4 Wh/kg). MnO2/V2O5/rGO//MrGO asymmetrical EC-SC device demonstrated reversible color changes from dark green to orange at the discharged and charged states, respectively. The significantly great electrochromic and supercapacitive performance revealed that MnO2/V2O5/rGO//MrGO is an outstanding electroactive candidate for the next generation of electrochromic supercapacitors.

Propane to propene oxide (PO) oxidation over V-containing mesoporous silica of SBA-3 structure has been studied using different oxidants (nitrous oxide, oxygen, and their mixture) in the temperature range 673–773 K. Electron spin resonance spectroscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy (XPS), as well as X-ray diffraction, temperature-programmed reduction with hydrogen (H2 TPR), and low-temperature N2 adsorption/desorption, were applied for characterization of fresh and spent catalysts. XPS spectra and H2 TPR profiles revealed a significant reduction of V-species as a result of propane oxidation with N2O alone, which leads to a decrease in both propane conversion and the space–time yield (STY) of PO. The use of an N2O–oxygen mixture as an oxidant of propane allows the vanadium valence to be stabilized at a level similar to the initial sample, which results in stable activity with time on stream. Propane conversion of 40%, propylene selectivity of 45%, and propylene oxide selectivity of 11%, corresponding to a STY of propylene oxide of about 15 g kgcat-1h−1, have been obtained, which makes these results very promising compared with the data reported in the literature. Vanadium catalyst used with only oxygen results in stable propane conversion with high total oxidation and stable propene selectivity, although the STY of PO is 10 times lower. N2O applied as the only oxidant results in rapid catalyst deactivation, and after 2 h on stream, STY of PO is only 2.5 g kgcat-1h−1.

A carbon nanotube (CNT)-mediated three-dimensional (3D) vanadium pentoxide (V2O5) nanoarchitecture with tunable morphology and translatable electrical and electrochemical functionality is developed via the step-wise chemical vapor deposition. Controlling the pressure, gas flow, and growth time, based on the collective understanding of the vapor-solid growth mechanism, enables the tailoring of V2O5 nanostructures into diverse functional structures including nanowires, nanoribbons, and nanoplatelets, where the nanoscale topography of an underlying CNT surface facilitates the conformal 3D morphing with extended scale, density, and surface area. An in-depth analysis of the V2O5-CNT interface confirms that the highly crystalline V2O5 nanocrystals are firmly connected to the CNTs with their structural and functional characteristics maintained. Here we demonstrate that the growth process and consequently emerging functionality of the 3D V2O5/CNT hybrid architecture can be translated to various practical frameworks such as porous metallic micromesh with further enhanced surface area and electrochemical conversion. The 3D V2O5/CNT hybrid architecture with application-specific structural tunability may thus be applicable to broader materials and device systems for energy conversion, sensing, photonics, and many others.

Excellent catalysts with low-temperature activity and relatively wide temperature window for selective catalytic reduction of NO with ammonia (NH3-SCR) are highly demanded in view of the practical treatment of NO. Herein, we have designed a highly active VOx-MnOx/CeO2 material based on the intrinsic requirement of SCR reaction for catalyst, namely redox sites and surface acid sites. The vanadium oxide and manganese oxide are highly dispersed over the ceria mesosphere via simple incipient wetness impregnation. The loading of manganese could introduce acid sites and enhance the redox property remarkably, while the loading of vanadium increases acid sites and weakens redox property. Through tentatively controlling the appropriate loading ratio of the two components, the optimal catalyst achieves a balance between redox property and surface acidity. The work shed light on the development of new SCR catalyst with superior low temperature activity, wide work temperature window and good hydrothermal stability.

A hybrid negative electrode was developed by combining a hydrothermally prepared copper-based metal-organic framework (Cu-MOF) and electrochemically synthesized reduced graphene oxide (rGO), which was labeled as MrGO. The MrGO composite was characterized using field emission scanning microscopy, Raman spectroscopy, Fourier transform infrared spectrometry and X-ray diffraction to confirm the presence of both Cu-MOF and rGO. Cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance spectroscopy (EIS) were carried out to study the electrochemical properties of the MrGO negative electrode for asymmetric supercapacitor (ASC) application. The EIS analysis of the MrGO electrode revealed the lowest charge transfer resistance of 0.95 Ω compared to rGO (23.73 Ω) and Cu-MOF (10.23 Ω). The electrochemical measurements were performed on the MrGO electrode at a negative operating potential (−0.4 to 0 V) to emphasize the hybrid MrGO as a high-performance negative electrode. The novel ASC was then constructed utilizing the vanadium oxide/reduced graphene oxide (VrGO) as the positive electrode and the hybrid MrGO as the negative electrode. The VrGO//MrGO ASC device was successfully delivered a superior specific capacitance (483.9 F/g) and enormous specific energy (31.2 Wh/kg). The inclusion of incredibly conductive rGO in the MrGO electrode could synergistically enhance the cycling stability (92% over 4000 CV cycles) of the VrGO//MrGO ASC device.

Threshold switching (TS) devices have evolved as one of the most promising elements in memory circuit due to their important significance in suppressing crosstalk current in the crisscross array structure. However, the issue of high threshold voltage (Vth) and low stability still restricts their potential applications. Herein, the vanadium oxide (VOx) films deposited by the pulsed laser deposition (PLD) method are adopted as the switching layer to construct the TS devices. The TS devices with Pt/VOx/Pt/PI structure exhibit non-polar, electroforming-free, and volatile TS characteristics with an ultralow Vth (+0.48 V/−0.48 V). Besides that, the TS devices also demonstrates high stability, without obviously performance degradations after 350 cycles of endurance measurements. Additionally, the transition mechanism is mainly attributed to the synergistic effect of metal-insulator transition of VO2 and oxygen vacancies. Furthermore, the nonvolatile bipolar resistance switching behaviors can be obtained by changing oxygen pressure during the deposition process for switching films. This work demonstrates that vanadium oxide film is a good candidate as switching layer for applications in the TS devices and opens an avenue for future electronics.

Elemental doping is the main means to regulate the phase transition of vanadium oxide (VO2); however, the effects of low valence elemental (

Selective catalytic reduction using NH3 (NH3-SCR) is a chemical process that is used for the elimination of NOx (NO and NO2). Although current vanadia-based catalysts need a high reaction temperature, which leads to deactivation of the catalysts, bulk vanadium oxide showed the potential for NH3-SCR at a low temperature below 150 °C. We investigated a method for synthesis of vanadium oxide with a large surface area using an organic acid to enhance its NH3-SCR activity. Vanadium oxide catalysts were synthesized from ammonium metavanadate (NH4VO3) and organic acids (oxalic acid, succinic acid, malic acid and citric acid). When carboxylic acids (oxalic acid and succinic acid) were used as the organic acid source, the surface area of the catalysts increased up to 41 cm2 g−1, which was larger than that of vanadium oxide synthesized without an organic acid and with hydroxy acid. SEM and TEM measurements showed that vanadium oxide catalysts synthesized by the calcination of vanadyl oxalate at 300 °C (V2O5-OX_300) formed a pore structure that contributed to the increase in surface area. An increase in the number of acid sites and redox sites, which is important for NH3-SCR to proceed, was confirmed from NH3-TPD and H2-TPR measurements for V2O5-OX_300. The NO conversion of V2O5-OX_300 (47 % at 100 °C) was higher than that of the catalysts synthesized from only NH4VO3 (19 % at 100 °C), indicating that vanadium oxide catalysts synthesized using carboxylic acid have the low-temperature NH3-SCR activity due to the increase in their surface area.

Rechargeable aqueous zinc-ion batteries (ZIBs) have become a research hotspot in recent years, due to their huge potential for high-energy, fast-rate, safe and low-cost energy storage. To realize good electrochemical properties of ZIBs, cathode materials with prominent Zn2+ storage capability are highly needed. Herein, we report a promising ZIB cathode material based on electrochemically induced transformation of vanadium oxides. Specifically, K2V6O16·1.5H2O nanofibers were synthesized through a simple stirring method at near room temperature and then used as cathode materials for ZIBs in different electrolytes. The cathode presented superior Zn2+ storage capability in Zn(OTf)2 aqueous electrolyte, including high capacity of 321 mAh/g, fast charge/discharge ability (96 mAh/g delivered in 35 s), high energy density of 235 Wh/kg and good cycling performance. Mechanism analysis evidenced that in Zn(OTf)2 electrolyte, Zn2+ intercalation in the first discharge process promoted K2V6O16·1.5H2O nanofibers to transform into Zn3+xV2O7(OH)2·2H2O nanoflakes, and the latter served as the Zn2+-storage host in subsequent charge/discharge processes. Benefiting from open-framework crystal structure and sufficiently exposed surface, the Zn3+xV2O7(OH)2·2H2O nanoflakes exhibited high Zn2+ diffusion coefficient, smaller charge-transfer resistance and good reversibility of Zn2+ intercalation/de-intercalation, thus leading to superior electrochemical performance. While in ZnSO4 aqueous electrolyte, the cathode material cannot sufficiently transform into Zn3+xV2O7(OH)2·2H2O, thereby corresponding to inferior electrochemical behaviors. Underlying mechanism and influencing factors of such a transformation phenomenon was also explored. This work not only reports a high-performance ZIB cathode material based on electrochemically induced transformation of vanadium oxides, but also provides new insights into Zn2+-storage electrochemistry.

The emergency of high-power electrical appliances has put forward higher requirements for the power density of lithium-ion batteries. Vanadium oxides with large theoretical capacities and high operating voltages are considered as prospective alternatives for the cathode of a new generation of lithium-ion batteries. However, the poor rate and cycling performance caused by the sluggish electrons/lithium transportation, irreversible phase changes, vanadium dissolution and large volume changes during the repeated lithium intercalation/deintercalation hinder their commercial development. Several optimizing routes have been carried out and extensively explored to address these problems. Taking V2O5, VO2(B), V6O13, and V2O3 as examples, this article reviewed their crystal structures and lithium storage reactions. Besides, recent progress in modification methods for the electrochemical insufficiencies of vanadium oxides, including nanostructure, heterogeneous atom doping, composite and self-supported electrodes has been systematically summarized and finally, the challenges for the industrialization of vanadium oxide cathodes and their development opportunities are proposed.

The effect of Ga, V, and Zr content on the structural properties and the catalytic behavior of H-ZSM-5 monolithic catalysts-supported gallium oxide, vanadium oxide, and zirconium oxide in the oxidative dehydrogenation of propane (ODHP) have been investigated in a continuous tubular microreactor using CO2 as a mild oxidant. The SEM-EDX confirmed the homogeneous distribution of metal oxides within printed metal oxide/H-ZSM-5 monolithic catalysts The ODHP reaction was carried out in the absence of CO2 (5 mol% propane, balanced with N2) and presence of CO2 (2.5 mol% propane, 5 mol% CO2 balanced with N2) at 500, 550, 600, and 650 ℃, 1 bar, and a space velocity of 4500 mL/gcat.hr. Among all synthesized Ga, V, and Zr/H-ZSM-5 monolithic catalysts, 15V-15Zr@ZSM-5 catalyst exhibits both high activity and stability for dehydrogenation of propane, with a propane conversion of 38 % and propylene selectivity of 90 % without any observable trend of benzene, toluene, xylene (BTX) production and catalyst deactivation in 6 h time on stream. The catalyst’s stability is also enhanced by the introduction of CO2. In the absence of CO2, more coke formation was observed which was in addition to the reduced conversion of propane and propylene selectivity by ∼1−5 %.

As a result of prices of fossil fuels and the increased energy demand, reasonable utilization of renewable energy sources has become a global topic, rechargeable aqueous zinc-ion batteries (ZIBs) are considered as the large-scale energy storage because there is an abundant zinc source, and ZIBs provide reliable safety, eco-friendliness, and high specific capacity. Nevertheless, the limited electroactive sites and low electrical conductivity of vanadium oxide (V2O5)-based cathode for ZIBs inevitably destabilizes the energy storing reactions, impeding the diffusion of zinc ion and electron movement. Here, to lower the insertion energetics and diffusion barriers of zinc ion, we reported iron (Fe)-doped V2O5 with the nanorod architecture by utilization of electrospun polyacrylonitrile fiber templates; these exhibited a high energy density of 540 W h kg−1 at a power density of 600 W kg−1, and a good capacity retention of 85% after up to 160 cycles. The Fe-doping effects in V2O5 matrix with the nanorod architecture provides abundant contact with electrolyte, an increased electrical conductivity, and shortened ionic diffusion distance during electrochemical processes, facilitating overall energy-storing performance. This work provides a necessary strategy for designing next-generation high-performance energy storage devices.

Perspective Rechargeable aqueous zinc-ion batteries (AZIBs) have gained increasing attention owing to their low cost and high safety. Although hydrated vanadium oxides exhibit rich redox chemistry and open layer architecture, the insertion of multivalent Zn2+ during cycling inevitably leads to host collapse and severe vanadium dissolution. Accordingly, various ions and conducting polymers have been introduced into the interlayer to produce vanadium bronzes with a robust crystal structure. However, these pre-intercalated vanadium bronzes demonstrate limited improvement and still face the challenge of metal ion displacement and confusing reaction mechanisms. Herein, we report a novel molecular bronze with intercalated 3-phenylpropylamine for use as an AZIB cathode, which produces an ultrahigh interlayer of 18.0 A. The cathode delivered an improved capacity of 420 mAh g−1 at 0.1 A g−1, an impressive rate capability of 158 mAh g−1 at 35 A g−1, and an outstanding lifespan with a capacity retention of 94% over 1200 cycles at 2A g−1. Furthermore, the reaction mechanism of H+/Zn2+ co-insertion was investigated in detail. This work proves that this strategy is universal for vanadium oxide bronzes and opens a new avenue for the fabrication of novel molecular bronzes as advanced AZIB cathodes.

Rechargeable aqueous zinc-ion batteries (ZIBs) are regarded as the next promising large scale energy storage systems owing to their low cost, high safety and environmental friendliness. Vanadium-based materials are one of the most important cathodes of ZIBs due to their high abundance and multielectron transfer of various oxidations of vanadium. Nevertheless, the strong electrostatic interaction between Zn2+ and cathodes, intrinsic poor electronic conductivity and solubility of vanadium-based cathodes in electrolytes bring about inferior electrochemical performance. In this work, we introduce aliovalent Cr3+ into the interlayer of hydrated vanadium oxide (Cr-VOH) as pillar to significantly increase the structural stability and electrochemical reversibility. The pre-intercalation of Cr3+ also provides an enhanced electronic conductivity and fast Zn2+ diffusion dynamics, enabling superior Zn2+ storage performance of the Cr-VOH cathode. As a result, the Cr-VOH cathode exhibits a high reversible discharge capacity of ~380 mAh g−1 at 50 mA g−1, excellent rate capacity of 166 mAh g−1 at 8 A g−1 and prolonged cycling stability over 500 cycles. Furthermore, it displays a high energy density of 273.6 W h kg−1 at 0.05 A g−1 and the power density of 4960 W kg−1 at 8 A g−1, contributing to the practical application potential of aqueous ZIBs.

Layered vanadium oxides have been promising cathodes for rechargeable aqueous zinc ion batteries (AZIBs) owing to multiple valences of vanadium and relatively high interplanar spacing. However, it undergoes significant capacity decay due to vanadium dissolution and structural instability during cycling, especially at low current densities. Herein, PANI-intercalated V2O5 ((PANI)xV2O5, PAVO) hybrid bronzes with an ultra-high interlayer spacing of 13.9 A for use as an AZIB cathode have been reported. The inserted polyaniline not only acts as structural pillars because of the hydrogen bond between -NH2 group and V-O layer but also plays the role of ‘H+’ reservoir to prevent V-O matrix from H+ attacking. Accordingly, PAVO cathode delivers a specific capacity of 350 mAh g−1 with a capacity of ~90% over 100 cycles at a current density of 0.1 A g−1, which operates for about 1 month. This study unveils the dissolution mechanism of vanadium-based electrodes and improves the stability and electronic conductivity with organic molecule intercalation. Besides, the intercalation of guest molecule generates pros and cons (favorable higher interlayer, while adverse steric hindrance) to the Zn2+ diffusion and accordingly presents a different rate performance when compared to most of the previously reported work. Therefore, a new set of molecular-scale hybrid bronzes would be designed to achieve an optimized performance in the future.

Vanadium oxides (VOx) have been studied extensively for applications in thermochromic materials, electrochomics, and infrared detectors due to their unique phase transition characteristics. However, various vanadium oxide phases usually occur under different deposition conditions due to their particularly complex vanadium-oxygen system. In this research, V3O7, VO2(B), VO2(M), and V2O5 thin films were obtained as pure or mixed phases by controlling the substrate temperatures between 250 °C and 400 °C during magnetron sputtering. The microstructure and phase composition of vanadium oxide thin films were characterized and analyzed using X-ray diffraction and Raman spectroscopy. The phase evolution was dependent on the substrate temperature and could be clarified. Metastable V3O7 and VO2(B) phases were obtained at substrate temperatures of 250–300 °C, while stable VO2 and V2O5 phases were obtained at 350–400 °C. The surface morphology and optical properties of vanadium oxide thin films with different substrate temperatures were investigated in detail. Our results provide methods for transforming vanadium oxide phases under well controlled substrate temperatures.

Herein we show a construction of high-performance supercapacitor electrode made of cerium vanadate uniformly glazed over polypyrrole (CeVO4/Ppy) nanostructures by a simple hydrothermal method, which was characterized by various analytical techniques. Electrochemical studies on CeVO4/Ppy/Ni foam with 1 M KOH show a maximum specific capacitance of 1236 F/g at a current density of 0.75 A/g. These salient features, together with smart interactions between the interconstituents, CeVO4 and Ppy, lead to high conductivity, specific capacitance, and cycling stability with retention of 92.6% capacitance in 10,000 cycles of GCD curves. Additionally, the asymmetric supercapacitor based on activated carbon (AC), AC//CeVO4/Ppy device delivers a high specific capacitance of 116 F/g and energy density of 52.2 Wh/Kg at power density of 675.9 W/kg along with high capacity retention of 77.80% after 10,000 cycles. This system could be scaled up to large-scale production of high power devices, which opens up lot of opportunities in modern electronic industrial applications.

Perovskite solar cells have been studied extensively in the area of perovskite solar cells because they have a comparatively free hysteresis. Through fabrication of a perovskite solar cell based on a vanadium oxide buffer, this study clarified the mechanism of electron and hole transport in the laminated layer upon irradiation with light. The power conversion efficiency (PCE) of the Vanadium (Ⅳ) oxide (VO2) sputtering process device was approximately 13% and with the spin-coating process was 8.5%. To investigate the physicochemical origin of such PCE differences depending on the process type, comprehensive band alignment and band structure analyses of the actual cell stacks were performed using X-ray photoelectron spectroscopy depth measurements. Accordingly, it was found that the inconsistent valence band offset between the perovskite absorption layer and V2O5 layer as a function of the VO2 process type caused a difference in the hole transport, resulting in the difference in the efficiency.

Vanadium-based cathodes for zinc-ion batteries (ZIBs) hold a great promise for next-generation energy storage systems due to their amazing diversity, relatively high capacity and excellent stability. Unfortunately, the specific capacity of current vanadium-based electrodes is intrinsically limited by zinc site density in crystal structures, probably attributing to the ignore of exception energy storage mechanism in cationic insertion/extraction. Herein, a new energy storage mechanism in the vanadium oxide-based ZIB system via cationic conversion reactions was demonstrated for the first time. At the force of electric and weak acid conditions, the oxygen-doped vanadium nitride (O-VN) cathode was firstly electrochemically oxidized into vanadium oxide and vanadium cations via in-situ activation; the cations would be reduced to V2O3 that depositing on the surface of the electrode in the discharge process; and subsequently the V (III) species could be oxidized back to the cations dissolving into electrolyte upon charging. First-principle density functional theory (DFT) calculations confirm the reversible characteristics of these reactions. Owing to these cationic conversion reactions together with contributions from zinc ion de/intercalation, the O-doped VN cathode delivered an ultrahigh discharge capacity of 705 mAh g−1 at 0.2 A g−1. This work continues to develop the energy storage mechanism of vanadium-based cathode and reveals the arrival of a new era for high-capacity ZIBs.

In the present work vanadium oxide (V2O5) was prepared by simple and direct sol–gel method by using ammonium metavanadate as precursor in the presence of ammonia as complexing agent. For structural and morphological analysis of V2O5 different characterization techniques were used. X-Ray Diffraction and Fourier Transform Spectroscopy were used for structural identification and functional group detection. The morphology of prepared material was studied by Scanning Electron microscopy technique. For band gap measurement (optical study) of V2O5, the UV–Visible Spectrophotometer techniques were used. Finally the Photocatalytic activity of the calcinated product for Methylene Blue (MB) dye was studied. The percentage of degradation and rate constant also calculated. The present work shows the good photocatalytic activity of V2O5 for hazardous MB dye and degradation take place in this case is about 75%. Thus V2O5 is promising material for photocatalytic activity.

In this development work an attempt has been made to investigate the effect of doping elements i.e. tungsten, molybdenum and titanium in vanadium oxide thin films. Various thin films have been developed by co-sputtering process. The phase and elemental analysis were studied by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX), respectively. The thermo-optical properties i.e. absorptance (αs), solar reflectance (ρs), solar transmittance (τs) and IR emittance (ɛir) were investigated and correlated the doping elements effect in vanadium oxide thin films.

Depending upon the type of external stimuli, ‘Chromogenic’ materials are generally classified as photochromic, thermochromic, electrochromic and gasochromic materials where the external stimuli are light (photon), temperature, applied electric field and gaseous atmosphere (for e.g., H2 gas), respectively. Among other analogues, thermochromic materials are part of larger class of ‘Intelligent’ or ‘Smart’ materials. These materials change their color upon heating. More generally speaking, their functional properties change with temperature. Vanadium oxides belong to this group of smart, thermochromic material. The thermodynamically stable variant of vanadium oxide, V2O5 is chosen in current study. The band gap of V2O5 synthesized by wet-chemical process, was observed to show dependence on the post heating temperature. This study suggest a possibility of band gap tuning by simple heat treatment.

Monitoring the highly volatile dimethylamine (DMA) vapour pays an important issue for the health and safety of humans. The atomization requires an electronic nose for detecting and controlling the toxic gases in the environment. The binary metal oxides of Titanium dioxide (TiO2) and Vanadium oxide (VOx) have been used for gas/vapour sensing applications for the past few decades. However, the binary metal oxides have low selectivity and sensitivity issues in real-time applications. Therefore, mixed metal oxides are attractive alternates for gas sensing application. The mixed metal oxide TiO2-VOx thin film was deposited by reactive co-sputtering technique and investigated for their structural, morphological, and sensing properties. For the first time, we report the DMA vapour sensing properties of TiO2-VOx at room temperature. Among many vapours, such as methanol, ethanol, formaldehyde, isopropanol, acetone, and DMA, the TiO2-VOx is highly selective towards DMA than the other binary oxides VOx and TiO2. The DMA vapour sensing studies proves that the deposited mixed metal-oxide had better sensing response of ~ 3.6 to a minimum concentration of 10 ppm at room temperature than binary oxides of VOx and TiO2.

In the present work, the corrosion inhibition properties of two borated vitreous phases for mild steel in 1.0 M HCl were investigated by using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The vitreous samples (P1 and P2) were synthesized from ammonium dihydrogenphosphate ((NH4) 2HPO4), vanadium oxide V2O5, bismuth oxide Bi2O3, boric acid H3BO3. The vitreous phase compositions were correlated with the Bi2O3-B2O3- (0,5V2O5 −0,5P2O5) system by a stoichiometric mixing. The synthesized samples were characterized by Fourier-transform infrared (FT-IR). Obtained results show that both vitreous phases act as good corrosion inhibitor for mild steel in 1.0 M HCl. Vitreous phases are found to be cathodic inhibitors, and inhibition efficiency of about 73% (P1) and 72% (P2) are obtained at 200 ppm. The effect of inhibitor concentration and temperature on the corrosion rate of mild steel were studied.

In today's sophisticated world, the need for electric energy is increasing every day. Therefore, it is essential to manufacture electrode materials to store electric energy. Nickel, bismuth, and cobalt vanadium oxides are considered a member of a group of the best anodes in energy storage applications. In this study, three kinds of anode materials were analyzed for their better electrochemical behavior. Hydrothermal method was preferred for all the synthesis processes. The basic characterization studies such as X-ray diffraction, photoluminescence, Raman, and Fourier transform infrared confirmed the presence of nickel, bismuth, and cobalt vanadium oxides. The highest specific capacitance value of 426.11 F/g in cyclic voltammetry and 285.65 F/g in galvanostatic charge–discharge (GCD) measurements was obtained for the cobalt vanadium oxide samples. Furthermore, stability test in GCD showed its 83.64% capacitive retention over 5000 cycles at a high (5 mA/g) current density.

Carbide coatings have been used to enhance the lifetime service of molds used for hot and cold forging, extrusion and powder metallurgy which are subjected to abrasive forces. Thermal reactive diffusion (TRD) process via molten salt bath is one of the coating processes suitable for the mentioned applications. The process has many advantages including excellent adhesion to the substrate as well as cost efficiency over other similar surface coating methods. The novelty in this research is the formation of hard carbide coatings using two separate oxide baths containing chromium oxide (Cr2O3) and vanadium oxide (V2O5). The coatings were produced on W1 tool steel by using TRD method via molten salt baths at 1000 °C for 8, 10 and 12 h, respectively. Phase structure, composition and microstructure of the coatings were analyzed by scanning electron microscopy (SEM), electron probe micro-analyzer (EPMA), and X-ray diffraction (XRD). The hardness of the coatings was evaluated by micro-indentation test. The results showed that chromium carbide and vanadium carbide coatings are formed successfully on the substrate with chemical formula Cr7C3 and VC, respectively. Vanadium carbide layer showed higher hardness (1854 HV) relative to the chromium carbide layer (1782 HV). However, its thickness (16 μm) was relatively lower than that of the chromium carbide layer (20 μm) after similar immersion time of 12 h. Moreover, it was found that, while the coating thickness increases with time, there is a specific time to reach the optimum thickness for each type of coatings.

Graphene is a type of promising electrode material for high-energy and high-power density supercapacitors, but its electrochemical performance is greatly limited by the restacking problem. In this work, we reported a facile approach to synthesis graphene with chemically bonded vanadium oxide (VOx) nanoparticles and demonstrated that chemically-bonded VOx nanoparticles can effectively prevent the graphene sheets from restacking and hence improve the electrochemical performance. The capacitance of VOx-bonded graphene increases to 272 F/g compared to 183 F/g of pristine graphene in 1 M H3PO4 aqueous electrolyte at 2 A/g. The VOx-bonded graphene also showed improved rate capability in both H3PO4 and ionic liquid electrolytes. The capacitance retention increases to 54.5% from 28.5% at 100 A/g (compare to 2 A/g) in H3PO4 and increases to 65.1% from 46.3% at 2 A/g (compare to 0.2 A/g) in neat ionic liquid. A high energy density of 84.4 Wh/kg is obtained within the voltage window of 4 V in ionic liquid. Even at a high-power density of 1000 W/kg, the VOx-bonded graphene shows a high energy density of 47.3 Wh/kg.

Effects of V and V-based compounds (VC, VO, VO2) on hydrogenation performances of the Mg17Al12 (110) surfaces are studied by first principles calculations. Results indicate that V and V-based compounds are stably adsorbed on the (110) surfaces. Additionally, the V-doped Mg17Al12 (110) systems are simulated. Calculations indicate that compared with the pure (110) system, H2 adsorption and dissociation on the Mg17Al12 (110) surfaces with adding V, VC, VO, and VO2 are dramatically promoted. Particularly, H2 are spontaneously dissociated on the vanadium oxide-adsorbed (110) surfaces. Analyses of density of states for the VO-adsorbed and VO2-adsorbed systems exhibit stronger hybridizations between V d sates and H s states, leading to the improvement of hydrogenation for the Mg17Al12 (110) surface. The vanadium oxide displays a preferred catalytic effect in our investigations, and the relative catalytic mechanism is revealed.

Thermochromic materials have attracted the attention of scientific and technological researchers due to their ability to change color depending on the temperature. Vanadium dioxide (VO2) is capable of considerable polymorphs and has aroused interest mainly because its metal–insulator transition (MIT) presents a thermochromic characteristic at a relatively low temperature. This work aimed to obtain vanadium oxide nanostructures using hydrothermal synthesis to tune the MIT temperature. Ammonium metavanadate or vanadium pentoxide was used as a precursor of vanadium, oxalic acid as a reducing agent, and sodium molybdate as an additive. The starting materials were homogenized and inserted in a hydrothermal reactor at 180 °C. After 24 h of synthesis, part of the resulting product was heat-treated at 400 °C for 3 h. The powders obtained were characterized by their structure, morphology, and thermal properties. The results showed a fiber/rod-shaped VO2 (M) morphology. Distinct strategies were used to obtain the crystalline phase of interest (VO2(M)), and the presence of a reversible change occurring at ~68 °C was evaluated according to the parameters from the VO2 phase transition. The addition of sodium molybdate favored a 22% reduction in the MIT temperature when the precursor used was vanadium pentoxide, indicating possible doping in the structure increased the effects of smaller crystallite size and the presence of crystalline phases. This work opens new perspectives for applications of the vanadium oxides obtained, such as in thermal sensors and/or intelligent materials.

The intercalation and conversion compounds have long been exploited in aqueous zinc-ion batteries such as Prussian blue, VS2, Zn0.25V2O5, MnO2 and so on. However, the lattice distortion of host materials during Zn ions insertion is the major issue with cycling stability. Metastable-phase vanadium oxide with bilayer structure, low crystallinity and interstitial water molecules may decrease lattice distortion, leading to long cycle stability. Herein we demonstrate H11Al2V6O23.2 (HAVO) microspheres with large interlayer distance (d001 ​= ​1.336 ​nm) as cathode materials for zinc-ion batteries. The Zn ions insertion/extraction behaviors are investigated deeply. Ex-situ XRD and Raman spectra of HAVO collected at various states show no shift during battery operation, indicating the lattice distortion is nearly negligible. In addition, the lattice structure is well maintained even after 1000 cycles and the HAVO delivers an outstanding reversibility (88.6% capacity retention after 7000 cycles).

Zn ion batteries show great potential for large-scale energy storage owing to their low-cost, safe and environment-friendly features. There is an urgent need for cathode material with high-energy-density and long-service-life. Vanadium-based cathodes would be particularly desirable due to the bi-electronic transfer reaction (V5+/V4+/V3+). Herein, we present a reversible V3+/V5+ double redox in lithium vanadium oxide (LiV3O8) with the insertion of Zn2+ for ZIBs. In this way, six-electron transition in LiV3O8 was achieved with only 7.64% volumetric expansion, yielding the highest capacity of 557.5 ​mA ​h ​g−1, and good cycling retention of 85% over 4000 cycles. The use of V3+/V5+ double redox will open-up new opportunities for designing vanadium-rich cathodes for high-performance Zn ion battery.

Vanadium oxides are promising candidates for cathode materials in aqueous zinc-ion batteries (ZIBs) with low cost and high capacity yet requirements for long cycling necessitate the development of increasingly stable structure. This study reports a structural engineering method by incorporating K+ into hydrated vanadium pentoxide (V2O5·nH2O, VOH) to achieve unique hydrated vanadate (KV12O30-y·nH2O, KVOH). In contrast to previously reported works, K+ introduction leads to a new phase of KVOH with faster ion diffusion kinetics and better long-term cycling stability. This work establishes an understanding of the role of K+ incorporation in KVOH which goes beyond its conventional categorization as an agent for interlayer spacing adjustment, reflecting in maintaining structure flexibility for effective Zn2+ insertion/extraction even at high rates, improving materials conductivity by the electron hoping of V4+/V5+ and acting as a stabilizer to accommodate structural contraction/expansion with smaller voltage hysteresis and higher reversibility. KVOH displays a remarkable capacity of 436 mAh g−1 at 0.05 ​A ​g−1, maintains 227 mAh g−1 at 10 ​A ​g−1, which is better than VOH and the majority of reported monovalent and multivalent metal ions introduced in vanadates. KVOH exhibits excellent cycling stability with 92% capacity retention over 3000 cycles at 5 ​A ​g−1, high energy density (308 ​Wh kg−1) and power density (7502 ​W ​kg−1), as well as improved energy efficiency. These characteristics recommend KVOH cathodes for use in high-performance aqueous ZIBs.

The effect of manganese and/or ceria loading of V2O5–MoO3/TiO2 catalysts was investigated for selective catalytic reduction (SCR) of NOx by NH3. The manganese and/or ceria loaded V2O5–MoO3/TiO2 catalysts were prepared by the wetness impregnation method. The physicochemical characteristics of the catalysts were thoroughly characterized. The catalytic performance of 1.5 wt% V2O5–3 wt% MoO3/TiO2 (V1.5Mo3/Ti) is greatly enhanced by addition of 2.5 wt% MnOx and 3.0 wt% CeO2 (V1.5Mo3Mn2.5Ce3/Ti) below 450 °C. Compared with the V1.5Mo3/Ti catalyst with NOx conversion of 75% at 275 °C, V1.5Mo3Mn2.5Ce3/Ti exhibits higher NOx conversion of 84% with good resistance to SO2 and H2O at a gas hourly space velocity value of 150000 h−1. The active manganese, cerium, molybdenum, and vanadium oxide species are highly dispersed on the catalyst surface and some synergistic effects exist among these species. Addition of MnOx significantly enhances the redox ability of the cerium, vanadium, and molybdenum species. Addition of Ce increases the acidity of the catalyst. More active oxygen species, including surface chemisorbed oxygen, form with addition of Mn and/or Ce. Because of the synergistic effects, appropriate proportions of manganese in different valence states exist in the catalysts. In summary, the good redox ability and the strong acidity contribute to the high NH3-SCR activity and N2 selectivity of the V1.5Mo3Mn2.5Ce3/Ti catalyst in a wide temperature range. And the V1.5Mo3Mn2.5Ce3/Ti catalyst shows good resistance to H2O and SO2 in long-time catalytic testing, which can be ascribed to the highly sulfated species adsorbed on the catalyst.

Experiment design-response surface methodology is applied in this work to model and optimize the oxidation of dibenzothiophene (DBT) using VOx-Ga-SBA-15 catalyst. The analyzed variables are the influence of the nature of the catalyst (V and Ga loading), the substrate/catalyst mass ratio (g DBT/g of catalyst) and the oxidant/substrate molar ratio (H2O2/DBT). The response analyzed is conversion of DBT at 15 min of reaction time. A set of response surfaces were obtained applying the Box-Behnken Design. Based on statistical methodology it was possible to find the best arrangement between the amounts of the gallium heteroatom and the vanadium active species. The higher levels of the objective function were obtained employing the catalyst with 4 wt.% of gallium and 6 wt.% of vanadium; the optimal ratio between g DBT/g of catalyst was 4 and the molar ratio between H2O2/DBT was 5. Gallium incorporation as heteroatom in tetrahedral position allowed the better anchorage of the active species of vanadium, generating a very well dispersed catalyst. The optimized catalyst minimized the mass transfer limitation and moreover, was active after several recycles. The best catalyst was likewise very active for the oxidation of the most refractory sulfur compounds as benzothiophene and 4,6-dimetyldibenzothiopene.

Modulation of the vanadium oxide epitaxial film metal insulator transition process through interfacial strain is a novel approach for controlling the properties of epitaxial vanadium oxide films, improving its scope for device applications. In this work, vanadium oxide films of various thickness were prepared and the effects of strains on the transition temperature were investigated. The vanadium oxide films exhibited compressive or tensile interfacial strain along their c-axis, the transition temperature varied in a range of 310–370 K owing to the effects of the interfacial strains. The tensile strain along the c-axis is correlated with an increase in transition temperature; however, the compressive strain along the c-axis leads to a decrease in transition temperature. The results show that the metal insulator transition process of vanadium oxide thin films can be regulated by interfacial strain. This work shows the feasibility of engineering the phase transition of epitaxial vanadium oxide films or the related devices through strain manipulating, which may be of great importance in practical applications.

Recent advances in in situ microscopy allow to follow the reaction dynamics during a catalytic surface reaction from ultra-high vacuum to 0.1 mbar, thus bridging a large part of the pressure gap. Submonolayer vanadium oxide films on Rh(1 1 1) have been studied during catalytic methanol oxidation in situ with spatially resolving imaging techniques. At 10−6–10−4 mbar VOx condenses into macroscopic circular islands that exhibit a substructure, consisting of a reduced island core and an oxidized outer ring. This substructure arises due to an oxygen gradient inside the VOx islands, which results in different coexisting 2D-phases of VOx on Rh(1 1 1). This substructure is also responsible for a “breathing-like” oscillatory expansion and contraction that the islands undergo under stationary conditions. Using density functional theory, the 2D-phase diagram of VOx on Rh(1 1 1) has been computed. The oscillatory behavior can be understood as a periodic phase transition between two 2D phases of VOx. With a newly developed near ambient pressure – low-energy electron microscope, it was shown that VOx islands disintegrate at 10−2 mbar, resulting in turbulent dynamics.

Present-day all-vanadium redox flow batteries (VRFBs) generally require high purity vanadium oxide as a raw ingredient. The chlorination procedure presents distinct technical advantages with regard to preparing high purity vanadium pentoxide (V2O5) using vanadium oxytrichloride (VOCl3) as a highly pure intermediate. To efficiently prepare high purity V2O5 from VOCl3, a single-step fluidized bed chemical vapor deposition (FBCVD) method was explored in the present work. Based on thermodynamic analyses, the direct and complete conversion of VOCl3 to V2O5 is difficult, and may result in a small amount of residual Cl in the product. Consequently, the effects of temperature and the H2O/VOCl3 molar ratio on the quantity of residual Cl were assessed. The Cl concentration was found to decrease with increasing temperature or increasing H2O/VOCl3 molar ratios. Additionally, Cl was determined to be present only in the form of Cl V bonds, while Cl H and Cl Cl bonds were not detected in a V2O5 product made at 200 °C with a H2O/VOCl3 molar ratio of 18. A Cl concentration of less than 0.05 wt% was obtained under the optimal synthesis conditions, demonstrating that the FBCVD method is a viable means of preparing high purity V2O5 via the gaseous hydrolysis of VOCl3.

Summary Rechargeable aqueous zinc-based batteries are very attractive alternative devices for current energy storage by virtue of their low cost and high security. However, the performance of vanadium oxide cathode strongly relies on the distance of interlayer spacing. Here, we employ layered PEDOT-NH4V3O8 (PEDOT-NVO) as a cathode material, which produces an enlarged interlayer spacing of 10.8 A (against 7.8 A for the single NVO) by effectively conducting polymer intercalation. This cathode material exhibits an improved capacity of 356.8 mAh g−1 at 0.05 A g−1 and 163.6 mAh g−1, even at the highest current density of 10 A g−1 (with a high retention from 0.05 to 10 A g−1), and features an ultra-long lifetime of over 5,000 charge-discharge cycles with a capacity retention of 94.1%. A combination of mechanism analyses and theoretical calculations suggest that the oxygen vacancies and larger interlayer spacing through polymer assistance account for the improved electrochemical performance.

Present study describes the synthesis of vanadium oxide nanorods (VONRs) via eco-friendly approach by using Tinospora cordifolia leaf extract. The as-synthesized VONRs were characterized by UV-Visible, FT-IR, XRD, EDX, SEM and TGA analysis. The size of VONRs were in the range of 10-40 nm. Further, the XRD data revealed that the as-obtained VONRs has typical orthorhombic phase. The biological activities such as anti-angiogenic, DNA binding and cleaving activity of the as-prepared VONRs were evaluated. Anti-angiogenic activity was carried by shell less Chorio Allantioic Membrane (CAM) assay, DNA binding and cleaving activity were performed using calf thymus DNA (CT-DNA) and supercoiled plasmid (pUC19) DNA, respectively. A marked reduction in the proliferation of capillaries around the zone of application of VONRs were observed in the anti-angiogenic assay, suggesting its biological potentiality. Furthermore, the cleavage of supercoiled DNA confirmed the involvement VONRs in the DNA interaction mechanism.

The demand of materials for energy conversion and storage is increasing to address the issues related to the depletion of fossil fuels. In the present study, oxygen deficient vanadium oxide (V2O3) has been synthesized in an autoclave at 500 °C for 4 h. The reaction temperature, time and atmosphere affect the pure phase formation of V2O3. The structural, morphological and surface characteristics of pure phase V2O3 has been analysed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), respectively. The phase transition with respect to temperature has been confirmed by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrocatalytic hydrogen evolution reaction (HER) activity has been studied in an acidic medium. The synthesized sample shows higher cyclic stability for 1000 cyclic voltammetry (CV) cycles. It also exhibits a lower Tafel slope of 81.2 mVdec−1. The electrochemical double layer capacitance (EDLC) measurements was done via CV measurements performed at various scan rates. The observed EDLC value of synthesized sample is 242.6 μFcm−2. The study predicts potential applications of V2O3 nano structures for electrochemical applications like HER and supercapacitors.

The mechanical and tribological characteristics of the VN/AlCrN multilayered coating films are investigated for cutting tools by using the arc ion plating (AIP) method with a rectilinear magnetic filtering system. The VN coating film forms vanadium oxide VxO1–x that has low friction coefficient on a surface above 500°C, whereas AlCrN coatings exhibit higher hot hardness and oxidation resistance. Therefore, the VN/AlCrN multilayer coatings are expected to demonstrate both superior lubricity and heat resistance, whose characteristics depend mostly on the combination of VN and AlCrN films. Moreover, some lower cutting force, tool wear, and tool flank temperature are obtained at high speed end milling of a prehardened stainless steel, as expected.

Thermal barrier coatings (TBCs) behave as thermal barrier on the aerospace and automotive components to operate at higher working temperatures and diminished cooling prerequisites. Thermal barrier coating is applied on the working substrates by plasma spraying method. Gadolinium oxide (GDO) is used to reduce thermal conductivity and resistance to corrosion and YSZ (Yttria-Stabilized Zirconia) is used to increase the fracture toughness. In the present study, high temperature corrosion behavior of plasma-sprayed single layer YSZ, single layer GDO and multilayer GDO /YSZ based TBCs will be studied by applying 45 wt% sodium sulphate and 55 wt% vanadium oxide as the salt solution at 1000 °C for 50 hrs.

Three samples that correspond to the evolution of optimal catalytic systems for the oxidative dehydrogenation of ethane have been synthesized and compared in terms of catalytic behavior and adsorption properties: (i) vanadium oxide supported on alumina, (ii) Sn-promoted NiO, and (iii) multicomponent MoVTeNbO with the M1 structure. The main difference in catalytic performance lies in the extent of the overoxidation of the ethylene formed, following the order VOx/Al2O3 > NiSnOx > MoVTeNb-M1. Accordingly, the selectivity to ethylene at medium and high ethane conversion follows the order MoVTeNb-M1 > NiSnOx > VOx/Al2O3. These results are confirmed by the relative reaction rates observed for the oxidation of ethane and the oxidation of ethylene. Microcalorimetry studies indicate that the heat of adsorption of both ethane and ethylene is the highest in the most selective MoVTeNb-M1 sample. Thus, the low olefin decomposition in the MoVTeNb-M1 catalyst is not due to weaker adsorption of ethylene but to the reduced ability of its active sites to activate ethylene. The same conclusion regarding the MoVTeNb-M1 catalyst can be drawn by FT-IR of adsorbed ethylene. On the other hand, NiSnOx active sites present a high overoxidation ability, as demonstrated by the notorious formation of oxygenated species, precursors of COx. However, the ethylene decomposition is rather mild because of the existence of many free Lewis sites not involved in the overoxidation reaction. In contrast, in the case of the VOx/Al2O3 catalyst, almost all active sites are involved in the oxidation path, so that the olefins decompose readily., The authors acknowledge the Spanish Ministry of Science, Innovation and Universities (MCIU) for their funding (RTl2018-099668-B-C21, MAT2017-84118-C2-1-R and MAT2017-87500-P) and FEDER. The authors from ITQ also thank Programa Severo Ochoa (SEV-2016-0683). A.A. acknowledges the Severo Ochoa Excellence Program for his grant (BES-2017-080329).