V2O5 Content Research Articles

Spectroscopic analysis of Nd3+-doped cadmium-vanadate invert glasses for near-infrared laser applications

Nd3+ activated CdO-V2O5 invert glasses were synthesized by the well-stablished melt quenching technique, using starting proportions of 95.0 and 5.0 mol% of CdO and V2O5, respectively. The XRD patterns revealed that the glass system remains amorphous up to 4.0 mol% of Nd3+. Such fact was mainly attributed to the low V2O5 content, which avoided the segregation of additional phases. The minimal addition of 0.1 mol% of Nd3+ reduced the direct and indirect glass bandgap energies from 2.79 to 2.66 eV, and from 2.48 to 2.13 eV, respectively. For higher Nd3+ contents, the bandgap energy was recovered, reaching values of 2.78 and 2.40 eV for direct and indirect allowed transitions, respectively. This fact was associated with a Burstein-Moss like effect, observed in semiconductors highly doped. The tail of the absorption edge revealed that the Urbach energy systematically grows with the addition of Nd3+, because of the creation of localized states into the bandgap. The Judd-Ofelt (JO) parameters obtained by least-square method from the experimental and theoretical oscillator strengths, were found in the Ω2 = 5.24-11.04 × 10−20 cm2, Ω4 = 2.26-4.47 × 10−20 cm2, and Ω6 = 2.85-6.28 × 10−20 cm2 range. Such values are close to those reported in other popular glass systems. The stimulated emission cross-section peak (σp) values calculated for the glass sample doped with 2.0 mol% resulted to be 0.26 × 10−20 cm2 (Nd3+: 4F3/2 → 4I9/2) and 0.81 × 10−20 cm2 (Nd3+: 4F3/2 → 4I11/2). The Nd3+ emission spectra, recorded upon 585 nm excitation (Nd3+: 4I9/2 → 4G5/2 + 2G7/2), showed the near-infrared Nd3+ emission bands at 881 nm (Nd3+: 4F3/2 → 4I9/2), 1063 nm (Nd3+: 4F3/2 → 4I11/2) and 1341 nm (Nd3+: 4F3/2 → 4I13/2), being dominated for that coming from the Nd3+: 4F3/2 → 4I11/2 transition. The overall emission reached the optimum intensity at 2.0 mol% of Nd3+, with a maximum quantum efficiency (ηQE) of 0.23. From the emission spectra important laser parameters such as gain bandwidth (σEMI(λp) × Δλem) and optical gain (σEMI(λp) × τR), were determined for the sample with the highest ηQE value. The σEMI(λp) × Δλem values resulted to be 11.3 and 32.0 × 10−27 cm3 for the Nd3+: 4F3/2 → 4I9/2, 11/2 transitions, respectively. The σEMI(λp) × τR parameter values were 11.1 and 35.3 × 10−25 cm2s for Nd3+: 4F3/2 → 4I9/2,11/2 transitions, respectively. The Inokuti-Hirayama model suggested that the Nd3+ cross-relaxation process might be dominated by an electric dipole-dipole interaction, inside Nd3+-Nd3+ clusters.

Influence of V2O5 on a sealing glass and self-healing VB2-glass composites

The effect of V2O5 addition on sealing properties of glasses with nominal composition (29-x)SiO2–23SrO–32BaO–4Al2O3–10B2O3–2P2O5-xV2O5 (where x = 2; 4; 6 mol.%) is reported. The glass transition temperature (Tg) decreases, and flow temperature increases with an increase in V2O5 content. 29Si and 31P MAS-NMR indicate that silicates are present mainly as Q2 groups, while phosphates are present as Q0 groups. 27Al MAS-NMR data shows that Al is 4-coordinated with oxygens, and11B NMR spectra show the presence of both BO3 and BO4 units. Composite materials were prepared by mixing glasses and vanadium di-boride VB2 (15 vol%). Sealing with Crofer-22 alloy was carried out with composite and revealed good bonding and tight interfaces.

Carrier Lifetime in 60Co Gamma and 1 MeV Electron‐Irradiated Tin‐Doped n‐Type Czochralski Silicon: Conditions for Improving Radiation Hardness

Herein, the results that determine some conditions for increasing the radiation hardness of 60Co gamma or 1 MeV electron‐irradiated tin‐doped n‐type Czochralski silicon (Cz n‐Si:Sn) are presented. These conditions are determined from the analysis of the formation kinetics of dominant radiation defects (namely, VO and SnV complexes) and the recombination of charge carriers through the electronic levels of these defects in samples with different concentrations of phosphorus and tin. It is shown that low‐resistivity Cz n‐Si with P doping levels >5 × 1014 cm−3 containing in addition [Sn] ≈1017–1019 cm−3 has a radiation hardening potential. In this material, the radiation degradation of carrier lifetime is several times smaller compared with Sn‐free n‐Si, whereas the conductivity compensation is negligible for both materials. The reduction of the lifetime degradation rate is due to a reduction of VO concentration in low‐resistivity Cz n‐Si:Sn.

Photocatalytic activity enhancement by composition control of mechano-thermally synthesized BiVO4-Cu2O nanocomposite

In this paper, BiVO4-Cu2O nanocomposites have been synthesized by a mechano-thermal method with a controlled composition of Bi2O3, V2O5 and Cu2O contents. The effects of milling time, heat treatment temperature and composition on the structure and microstructure of the prepared samples were studied. The optical properties and photocatalytic performance of the samples under visible light irradiation were studied by Diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and dye degradation. The BiVO4 and Cu2O contents in the nanocomposite were changed and the effects on the structural stability and photocatalytic performance were studied. X-ray diffraction (XRD) patterns showed that both BiVO4 and Cu2O contents were effective on the synthesis and stability of the monoclinic phase of BiVO4. Field emission scanning electron microscopy (FESEM) micrographs indicated semi-spherical nanocomposite particles with an average particle size of 100 nm. The heterostructure at the interface between Cu2O and BiVO4 was shown by Transmission electron microscopy (TEM) and proved by X-ray photoelectron spectroscopy (XPS) spectra. DRS results indicated the minimum band gap energy of 2.12 eV for BiVO4-10 wt% of Cu2O with a 10 wt% excessive V2O5 content. The PL result has shown the lowest rate of the recombination of electron-holes for this sample. Also, the maximum degradation of 97% has been obtained for methylene blue (MB) by this sample after 240 min of being irradiated in visible light region. The photocatalytic mechanism was determined using scavengers. The kinetics of MB and methyl orange (MO) degradations was compared to study the effect of pH on the photocatalytic performance.

Oxygen vacancy engineering of TaO x -based resistive memories by Zr doping for improved variability and synaptic behavior

Resistive switching (RS) devices are promising forms of non-volatile memory. However, one of the biggest challenges for RS memory applications is the device-to-device (D2D) variability, which is related to the intrinsic stochastic formation and configuration of oxygen vacancy (VO) conductive filaments (CFs). In order to reduce the D2D variability, control over the formation and configuration of oxygen vacancies is paramount. In this study, we report on the Zr doping of TaO x -based RS devices prepared by pulsed-laser deposition as an efficient means of reducing the VO formation energy and increasing the confinement of CFs, thus reducing D2D variability. Our findings were supported by XPS, spectroscopic ellipsometry and electronic transport analysis. Zr-doped films showed increased VO concentration and more localized VOs, due to the interaction with Zr. DC and pulse mode electrical characterization showed that the D2D variability was decreased by a factor of seven, the resistance window was doubled, and a more gradual and monotonic long-term potentiation/depression in pulse switching was achieved in forming-free Zr:TaO x devices, thus displaying promising performance for artificial synapse applications.

Development of a selective ammonia YSZ-based sensor and modeling of its response

In the present study, Au-V2O5 sensing material was tested as a sensing electrode for developing mixed-potential ammonia gas sensors. The results of gas sensing measurements indicated selective responses to NH3 while this selectivity was highly dependent on the temperature. Different V2O5 contents were tested in the sensing electrode. The results showed that by increasing V2O5 content from 15 wt.% to 50 wt.%, selective ammonia sensors could be achieved at 550 °C. The selectivity of Au-50 %V2O5 sensor was also confirmed in gas mixtures of CO, NH3, NO, and NO2 gases. Modeling of the sensor responses in the ammonia concentration range 2–40 ppm at four oxygen concentrations was performed based on mixed-potential theory. Nernst and Butler-Volmer equations with an electron transfer assumption were used for data modeling.

New Insights into the Penetration Depth of Sulfuric Acid and Leaching Effect in the Sulfuric Acid Curing-Leaching Process of Vanadium-Bearing Stone Coal.

In the process of sulfuric acid curing-leaching vanadium-bearing stone coal, the curing effect is very important. The main purpose of this study is to capture the difference in the curing effect between coarse and fine stone coal, with a V2O5 content of 0.88%. In this work, the effects of various factors such as sulfuric acid concentration, curing time, curing temperature, and different agents for curing on the leaching efficiency of vanadium were investigated by the comparison of the two size fractions. The results showed that the leaching efficiency of vanadium was 87.65% under the optimum curing conditions of 25 wt % sulfuric acid, curing time of 8 h, and curing temperature of 130 °C. It was clearly found that, under the same curing condition, the curing effect of fine stone coal was better than that of coarse stone coal. The penetration part of stone coal particles by sulfuric acid was loose, while the non-penetration part was dense after acid curing. Moreover, the penetration depth of sulfuric acid into the particles was mainly 0.5–0.7 mm on average. There was more sericite/illite in coarse leaching residues, which were mostly dense and hard carbonaceous siliceous slate. Thus, sulfuric acid was difficult to penetrate into and reach the interior of the particle, which resulted in that the leaching efficiency of coarse vanadium-bearing stone coal ore was lower than that of fine vanadium-bearing stone coal ore.

STRUCTURAL AND ELECTRICAL PROPERTIES OF (CDO)1-X (V2O5)X PREPARED BY PULSE LASER DEPOSITION TECHNIQUE FOR SOLAR CELL APPLICATIONS

In this work ,pure and doped(CdO)thin films with different concentration of V2O5x (0.0, 0.05, 0.1 ) wt.% have been prepared on glass substrate at room temperature using Pulse Laser Deposition technique(PLD).The focused Nd:YAG laser beam at 800 mJ with a frequency second radiation at 1064 nm (pulse width 9 ns) repetition frequency (6 Hz), for 500 laser pulses incident on the target surface At first ,The pellets of (CdO)1-x(V2O5)x at different V2O5 contents were sintered to a temperature of 773K for one hours.Then films of (CdO)1-x(V2O5)x have been prepared.The structure of the thin films was examined by using (XRD) analysis..Hall effect has been measured in orded to know the type of conductivity, Finally the solar cell and the efficiency of the CdO:V2O5 cells have been studied.

Regeneration of Catalytic Activity of CuO–Cu2O/In2O3 Nanocomposite towards Electrochemical Reduction of CO2 by UV Light Treatment

The deactivation of the electrocatalysts due to aging remains an issue, even though many electrocatalysts with very high faradaic efficiency (FE) have been developed. In the present work, we have put forth a facile approach for the regeneration of aged CuO–Cu2O/In2O3 nanocomposite along with a possible mechanism for the regeneration of activity of aged catalysts towards electrochemical reduction by regaining their oxygen vacancies (Vo) defects concentration by ultra-violet (UV) light treatment. The photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and electrochemical reduction of CO2 (ERC) measurements suggest that the decline in CO faradaic efficiency (FECO) can be attributed to the increase in Vo concentration beyond an optimum level upon aging. From the state-of-the-art combined experimental and theoretical investigation, we conclude that the regeneration of the active sites in the aged electrocatalysts by UV light treatment helps in regaining the electrocatalytic activity towards ERC.

Morphogenesis of Silicovanadate Glasses: Investigation of Physical Properties

In this article, we demonstrate the synthesis and various characterizations of silicovanadate glasses of xSiO2 (100-x)V2O5 for x = (10-50) mol%, glasses which are prepared by the melt quenching method. FTIR spectra analysis confirms dominant chemical bonds among silicon, vanadium, and oxygen elements as expected. The assigned chemical bonds are Si-O-Si, O-Si-O, V-O-V, V=O, Si-O-V, O-H from FTIR spectra. The IR spectra of all glass specimens were baseline corrected and deconvoluted to distinct peaks of chemical bonds in overlapped Gaussians with employing computer program. The chemical bond's position shifted and affected due to the addition of vanadium pentaoxide by the heat treatment process. The X-ray diffractions (XRD) patterns of glass samples exhibit partial crystalline nature for 10S90V and 50S50V that is influenced by high-temperature application. The differential thermal analysis (DTA) of base and heat-treated specimen determines the glass transition (Tg), crystallization, and liquidus temperature with prominent exothermic and endothermic reactions. It is seen that the pH of the glass specimens abruptly changes due to the surface effect of V2O5 while bulk effects become robust after about 30 minutes. The measured hardness of three glass samples shows high HV-values and a slight linear increment is observed for higher V2O5 contents. The current-voltage (I-V) characteristic connected to the electrical conductivity of the glass specimen (20S80V) shows a relatively higher and non-linear trend of conductivity which reveals the behavior of a semiconductor. Moreover, temperature-dependent electrical resistivity measurement of the same sample (20S80V) manifests the semiconducting nature up to 427 °C as well.

Effect of surface oxygen vacancy defects on the performance of ZnO quantum dots ultraviolet photodetector* *Project supported by the National Natural Science Foundation of China (Grant Nos. 62074148, 61875194, 11727902, 12074372, 11774341, 11974344, 61975204, and 11804335), the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2020225), the Open Project of the State Key Laboratory of Luminescence

The slower response speed is the main problem in the application of ZnO quantum dots (QDs) photodetector, which has been commonly attributed to the presence of excess oxygen vacancy defects and oxygen adsorption/desorption processes. However, the detailed mechanism is still not very clear. Herein, the properties of ZnO QDs and their photodetectors with different amounts of oxygen vacancy (VO) defects controlled by hydrogen peroxide (H2O2) solution treatment have been investigated. After H2O2 solution treatment, VO concentration of ZnO QDs decreased. The H2O2 solution-treated device has a higher photocurrent and a lower dark current. Meanwhile, with the increase in VO concentration of ZnO QDs, the response speed of the device has been improved due to the increase of oxygen adsorption/desorption rate. More interestingly, the response speed of the device became less sensitive to temperature and oxygen concentration with the increase of VO defects. The findings in this work clarify that the surface VO defects of ZnO QDs could enhance the photoresponse speed, which is helpful for sensor designing.

Regulation of oxygen vacancy within oxide pyrochlores by F-doping to boost oxygen-evolution activity

The development of cost-effective and durable oxygen evolution reaction (OER) catalysts is an essential prerequisite for hydrogen production through proton exchange membrane water electrolysis. Herein, a series of F-doped pyrochlore yttrium ruthenate Y2Ru2O7−δ-xFx (YRuOF) are designed via low-temperature fluorination of precursor oxides with polyvinylidene fluoride. Both X-ray photoelectron spectroscopy and transmission electron microscopy results confirm that F is doped into the pyrochlore crystal lattice, inducing the oxygen vacancies (VO). Importantly, the OER catalytic activity is positively correlated with VO concentration. The density functional calculation (DFT) reveals that the existence of VO enhances the metal-oxygen covalency of pyrochlore, which is conducive to the lattice oxygen evolution mechanism, hence greatly accelerating the OER kinetic. Consequently, the optimized YRuOF catalyst exhibits a greatly enhanced OER activity with an overpotential of ~235 mV at 10 mA cm−2 in comparison with that on undoped pyrochlore (~296 mV). Furthermore, such a F-doped YRuOF catalyst has a very good OER stability. This study provides an ideal perspective to develop highly efficient and durable YRuOF for the oxygen evolution reaction.

Investigations of defect structures for V4+ in CBPB glasses with distinct V2O5 contents

The defect structure, d-d transition and EPR parameters for V4+ in 10CaF2-(20-x)Bi2O3-60P2O5-10B2O3-xV2O5 (CBPB) glasses with distinct V2O5 contents x are theoretically investigated from the perturbation formulas for tetragonally compressed octahedral 3d1 clusters. Linearly decreasing cubic field parameter Dq or increasing g|| and g⊥ with x are suitably reproduced by linearly decreasing content function of Dq or decreasing and increasing content functions of covalence factor N and relative tetragonal compression ratio τ. The overall slightly increasing and decreasing average and anisotropy of hyperfine structure constants are illustrated as the cubic increasing content functions of core polarization constant κ and reduction factor H. These content dependences are ascribed to the modulations in local tetragonal compression, crystal-field strength and electron cloud distribution near V4+ with x. V2O5 as strong network modifier inducing depolymerization of phosphate long chains and Bi2O3 as network former and modifier exhibiting discontinuous changes with x may account for these modifications of the local structural properties.

Whole life cycle performance evolution of selective catalytic reduction catalyst in coal-fired power plants

Four typical coal-fired power plants were employed to explore the performance evolution within the whole life cycle of catalysts. The results revealed that the amount of active ingredients in the catalysts decreased over time. The content of V2O5 and WO3 in four units had decreased by 3.32%–32.8% and 12.9%–22.9% respectively. However, alkali metals and alkaline earth metals in flue gas were gradually deposited on the catalyst and led to catalyst poisoning, especially in two units due to arsenic poisoning. The specific surface area of catalysts decreased significantly in the first year of operation, accounting for 87.3%, 47.8%, 55.1% and 86.7% of the decline in the lifetime, which may be the main reason for the decline of catalyst activity during this period. The wall thickness of catalysts decreased linearly with the operation time in the lifetime. The relative activity of catalysts at the end of designed service lifetime was between 0.90 and 0.93, whereas the decrease range of SO2/SO3 conversion rate was within 15.4%–35.6%. Influenced by the catalyst design and the variations of practical operation conditions, the difference between the actual and designed service lifetimes of catalysts in the four units was 2.08%, 44.0%, 4.17%, and − 25.0%, respectively.

Facile Construction of Carbon Dots Layer and Oxygen Vacancies Simultaneously onto TiO2 to Enhance Photoreduction Activity

Main observation and conclusionWe reported a facile and green hydrothermal strategy to tailor the carbon dots layer (CDL) and oxygen vacancies (Vo) modified on TiO2, by using ascorbic acid as CDL precursor and Vo regulator. The amorphous CDL was uniformly coated on the surface of the as prepared CDL@TiO2–x composites by Ti‐O‐C bond. With the increase of carbon content, the amorphous CDL gradually became thicker, while the Vo concentration first increased and then decreased. 1.5 CDL@TiO2–x possessed the highest Vo concentration. With the decoration of CDL and Vo, the photoreduction properties of CDL@TiO2–x composites were significantly improved. Under simulated solar light and visible light, the reaction rates of 1.5 CDL@TiO2–x were 9.6 times and 216 times higher than that of pure TiO2, respectively. Interestingly, the results discovered that CDL and Vo influenced the properties of CDL@TiO2–x composites in different ways. The primary function of CDL was to improve the utilization of solar light, and the enhancement of the charge transfer ability was decided by Vo and CDL together. Our work provides a new strategy for the modification of TiO2 and sheds new light on the respective role of CDL and Vo when they coexist in the catalyst.

Pulse and Compliance Current-Dependent Negative Differential Resistance in BaTiO3/Nb:SrTiO3 Heterojunctions

The negative differential resistance (NDR) is closely related to the pulse and compliance current (CC) but not ferroelectric polarization in BaTiO3/Nb:SrTiO3 heterojunctions. The NDR feature shows an opposite trend on the positive (+VP) and negative pulse (−VP) and the same trend on pulse amplitude and width while maintaining the same polarity. When the applied pulse was small or short, the NDR characteristics are almost not influenced. With increase of the +Vp (−Vp) amplitude or width, NDR enhances (reduces) while shifting to a smaller (bigger) negative bias voltage (−Vb), and the low resistance state (LRS) reduces (enhances) while the high resistance state (HRS) almost remains unchanged. Furthermore, as CC increases, the NDR enhances markedly and barely shifts, while the LRS and HRS almost remain unchanged. Interestingly, the NDR location and LRS exhibit the same dependence on the amplitude/width of ±Vp and CC. The above behaviors of NDR can be attributed to the variance of oxygen vacancy (Vo) concentration and depletion layer width. It is beneficial for the development of NDR devices.

Achieving a Low-Voltage, High-Mobility IGZO Transistor through an ALD-Derived Bilayer Channel and a Hafnia-Based Gate Dielectric Stack

Ultrahigh-resolution displays for augmented reality (AR) and virtual reality (VR) applications require a novel architecture and process. Atomic-layer deposition (ALD) enables the facile fabrication of indium-gallium zinc oxide (IGZO) thin-film transistors (TFTs) on a substrate with a nonplanar surface due to its excellent step coverage and accurate thickness control. Here, we report all-ALD-derived TFTs using IGZO and HfO2 as the channel layer and gate insulator, respectively. A bilayer IGZO channel structure consisting of a 10 nm base layer (In0.52Ga0.29Zn0.19O) with good stability and a 3 nm boost layer (In0.82Ga0.08Zn0.10O) with extremely high mobility was designed based on a cation combinatorial study of the ALD-derived IGZO system. Reducing the thickness of the HfO2 dielectric film by the ALD process offers high areal capacitance in field-effect transistors, which allows low-voltage drivability and enhanced carrier transport. The intrinsic inferior stability of the HfO2 gate insulator was effectively mitigated by the insertion of an ALD-derived 4 nm Al2O3 interfacial layer between HfO2 and the IGZO film. The optimized bilayer IGZO TFTs with HfO2-based gate insulators exhibited excellent performances with a high field-effect mobility of 74.0 ± 0.91 cm2/(V s), a low subthreshold swing of 0.13 ± 0.01 V/dec, a threshold voltage of 0.20 ± 0.24 V, and an ION/OFF of ∼3.2 × 108 in a low-operation-voltage (≤2 V) range. This promising result was due to the synergic effects of a bilayer IGZO channel and HfO2-based gate insulator with a high permittivity, which were mainly attributed to the effective carrier confinement in the boost layer with high mobility, low free carrier density of the base layer with a low VO concentration, and HfO2-induced high effective capacitance.

Vertical, dense and uniform V2O5 nanoneedle arrays on carbon foam for boosting electrochemical performance

For the preparation of nanomaterials applied in supercapacitors, a rational and controllable strategy is generally developed to optimize the framework and augment the properties of them to a great extent. In this paper, we demonstrate a novel 1D@3D microstructure nanocomposite of V2O5@CF that is by means of suitably regulating the concentration of V2O5, and effectively developing its application in the supercapacitor. First, the carbon foam (CF) acts as the framework owning to its distinctive three-dimensional structure, which was obtained from the carbonization of melamine foam (MF). Then, one-dimensional V2O5 nanoneedles are implemented by a one-step hydrothermal method and propagated vertically and uniformly on the surface of CF. In virtue of suitable regulation on the concentration of V2O5, the prepared V2O5@CF composite exhibits desirable microstructure and performance. The specific capacity of this 1D@3D nanocomposite reaches 220.6 C/g at the current density of 1.0 A/g, which maintains 74.5% of initial capacities after 5000 incessant charge/discharge cycles, exposing excellent durability. Furthermore, the assembled asymmetric supercapacitor based on the V2O5@CF composite possesses outstanding specific energy of 28.1 Wh/kg and specific power of 3772.3 W/kg. The electrochemical performance of V2O5@CF nanocomposite is primely promoted by the rational and controllable strategy of preparation, which broadens the application of V2O5 and carbon foam in supercapacitor.

A green approach for the preparation of nanostructured zinc oxide: Characterization and promising antibacterial behaviour

In the present study, nanostructured zinc oxide (ZnO) films have been successfully synthesized using fruit extract of Viburnum opulus L. (VO) on glass slides by successive ionic layer adsorption and reaction (SILAR) procedure. The impact of VO concentrations on the structural, morphological, optical, electrical, and antibacterial attributes of ZnO films has been investigated in detail. The samples' XRD patterns present a hexagonal crystal structure with a preferential orientation along the (002) plane. The crystallite size values of ZnO samples were found to be in the ranges from 14.88 to 9.23 nm. The supplementation of VO to the synthesis solution remarkably affected the surface morphological features of the ZnO films. The optical results demonstrated that band gap energy values of the ZnO films at room temperature were decreased from 3.20 to 3.07 eV as a function of VO content in the bath solution. The films' electrical properties were determined by impedance analysis in the frequency range of 20 Hz −1 MHz. Impedance-frequency measurements showed VO insertion to ZnO thin films cause an increase in impedance value at the low frequencies. Cole-Cole plots with a single semi-circle confirmed the contribution of grain and grain boundary for the electrical conduction process. The agar disk diffusion method was used to test the antibacterial properties of ZnO/VO inserted ZnO and inhibition zones were measured. VO inserted ZnO showed a stronger inhibitory effect on gram-positive bacteria Staphylococcus aureus (ATCC 25923) and gram-negative bacteria Escherichia coli (ATCC 35218) than ampicillin antibiotic used as a control group. In line with the promising bactericidal results of a new generation, VO inserted ZnO, the nanostructured product with this study, it can also be applied in multidrug-resistant clinical isolates obtained from patients.

Effect of melting condition on optical, FTIR and E.S.R properties of irradiated fluorophosphate glasses containing vanadium ions

Glasses from the system Na2O–CaF2–P2O5 with varying doping V2O5 (0.5, 0.75, 1%) were prepared under ordinary and reducing conditions. Multiple Characterizations including optical, FTIR and ESR spectral data were obtained for the prepared glasses before and after gamma irradiation (with a dose of 6 Mrad).Optical absorption spectrum of the undoped sample reveals strong and broad UV absorption with two peaks which are related to unavoidable traces of iron (Fe3+) ions contaminated within the chemicals used for the preparation of the glasses. The V2O5 doped glasses show two additional pronounced broad visible and near-IR bands which varied in intensity and position of their peaks with the V2O5 content and condition of melting. These distinct visible and near IR bands are assumed to be indicator for the presence for low valence trivalent and tetravalent vanadium ions with variable percents, in accordance with the included host fluoro-phosphate glass and different melting conditions. Gamma irradiation causes noticeable effect on the optical spectrum of the undoped glass but the spectra of V2O5-doped samples reveal pronounced shielding behavior. FTIR spectra of the prepared glasses show distinct vibrational bands due to asymmetric and symmetric vibrations of the phosphate groups of main (PO4) groups and together with the presence of some (PO3F) groups. The detailed FTIR spectra show minor variations with the V2O5 content or condition of melting. E.S.R results show distinct signals due to the presence of both trivalent and tetravalent vanadium ions which possess unpaired electrons in their outer electronic configurations. E.S.R data reveal limited variations in the intensity of the signals with varying V2O5 content or condition of melting and even upon gamma irradiation points out to the stability of V3+ and V4+ ions in the studied host fluorophosphate glass.