13718-26-8Relevant articles and documents
Sodium-vanadium bronze Na9V14O35: An electrode material for na-ion batteries
Abakumov, Artem M.,Akmaev, Alexey S.,Gorbunov, Mikhail V.,Kirsanova, Maria A.,Mikhailova, Daria
, (2021/12/29)
Na9V14O35 (η-NaxV2O5) has been synthesized via solid-state reaction in an evacuated sealed silica ampoule and tested as electroactive material for Na-ion batteries. According to powder X-ray diffraction, electron diffraction and atomic resolution scanning transmission electron microscopy, Na9V14O35 adopts a monoclinic structure consisting of layers of corner-and edge-sharing VO5 tetragonal pyramids and VO4 tetrahedra with Na cations positioned between the layers, and can be considered as sodium vanadium(IV,V) oxovanadate Na9V104.1+O19 (V5+O4)4. Behavior of Na9V14O35 as a positive and negative electrode in Na half-cells was investigated by galvanostatic cycling against metallic Na, synchrotron powder X-ray diffraction and electron energy loss spectroscopy. Being charged to 4.6 V vs. Na+/Na, almost 3 Na can be extracted per Na9V14O35 formula, resulting in electrochemical capacity of ~60 mAh g?1. Upon discharge below 1 V, Na9V14O35 uptakes sodium up to Na:V = 1:1 ratio that is accompanied by drastic elongation of the separation between the layers of the VO4 tetrahedra and VO5 tetragonal pyramids and volume increase of about 31%. Below 0.25 V, the ordered layered Na9V14O35 structure transforms into a rock-salt type disordered structure and ultimately into amorphous products of a conversion reaction at 0.1 V. The discharge capacity of 490 mAh g?1 delivered at first cycle due to the conversion reaction fades with the number of charge-discharge cycles.
Synthesis, Characterization, and Photocatalytic Activities of BiVO4 by Carbon Adsorption Hydrothermal Method
Niu,Guo
, p. 1661 - 1665 (2020/08/19)
A new idea of prepared method for BiVO4 nano-powders hydrothermal synthesis process was developed to avert the existent shortcomings of hydrothermal method. The thermal stability, phase structure, light absorption property, and morphology of the catalyst prepared were characterized by thermogravimetric analyzer (TG), X-ray diffraction (XRD), ultraviolet visible spectrophotometer (UV/Vis), and transmission electron microscopy (TEM), respectively. Using methyl orange (MO) as the target degradation material and a 500-W dysprosium lamp as the visible light source to investigate photocatalytic performance of BiVO4. We successfully prepared BiVO4 powders with small particle size, less agglomeration and uniform distribution by carbon adsorption hydrothermal method, and the absorption wavelength of light was red-shifted, these all rendered the absorption capacity of visible light region enhancing with 94 % high photocatalytic degradation rate of methyl orange at 60 min. And the possible mechanism was also discussed in this study.
High-performance NaVO3 with mixed cationic and anionic redox reactions for Na-ion battery applications
Su, Bizhe,Wu, Shuilin,Liang, Hanqin,Zhou, Wenchong,Liu, Junnan,Goonetilleke, Damian,Sharma, Neeraj,Sit, Patrick H.-L.,Zhang, Wenjun,Yu, Denis Y.W.
, p. 8836 - 8844 (2020/11/24)
Sodium-ion batteries (NIBs) are a potential low-cost alternative to lithium-ion batteries for large-scale energy storage, but many high-capacity NIB cathode materials undergo irreversible structural changes during charge and discharge, leading to fast capacity fading. Herein, monoclinic NaVO3 exhibits good cycle performance with high capacity as a cathode material for NIBs. In situ synchrotron X-ray diffraction studies show that the material structure is virtually invariant during Na+ (de)intercalation, with the a and b lattice parameters changing only by 0.13 and 0.19%, respectively. The material undergoes an oxygen redox reaction during initial charge while delivering a remarkable specific capacity of 245 mAh g-1 (1.2-4.7 V) with contributions from cationic (V4+/V5+) and anionic (O2-/O-) redox couples during discharge. The stable VO4 tetrahedral framework also enables the material to give superior rate and cycle capabilities, with a capacity of 164 mAh g-1 (67% utilization) at a current of 1000 mA g-1 (about 5C) and a capacity retention of 90% after 50 cycles. Density functional theory calculations further verify the stability of the material and the charge-discharge mechanism. This work can broaden the horizon for designing high-energy cathode materials with enhanced structural stability for sodium-ion batteries.
Stability of Polar Structure in Filling-Controlled Giant Tetragonal Perovskite Oxide PbVO3
Yamamoto, Hajime,Ogata, Takahiro,Sakai, Yuki,Azuma, Masaki
, p. 2755 - 2760 (2019/02/19)
The crystal structure and stability of a giant tetragonal phase in electron-doped Pb1-xBixVO3 (x = 0.1, 0.2, and 0.3) and hole-doped Pb1-xNaxVO3 (x = 0.1, 0.2, and 0.3) were studied. Electron doping effectively destabilized the tetragonal structure. The c/a ratio, spontaneous polarization, and tetragonal-to-cubic phase transition pressure systematically decreased with increasing Bi3+ substitution. In contrast, hole doping hardly affected the tetragonal distortion and structural stability. We showed that electron doping is an effective way to control the stability of the tetragonal phase of PbVO3 with a 3d1 electronic configuration.
Tailoring NaVO3 as a novel stable cathode for lithium rechargeable batteries
Chen, Long,Wu, Honglun,Wang, Huiming,Chen, Liang,Pu, Xiangjun,Chen, Zhongxue
, p. 224 - 231 (2019/04/17)
Vanadium-based compounds hold great promise as high capacity cathode candidate for future lithium rechargeable batteries. However, developing highly stable vanadium-based cathode materials with long cycle life remains a great challenge. Herein, we report a novel layered sodium vanadium oxide, NaVO3, as a promising cathode electrode contender. This material is capable of delivering a capacity of 224.8 mAh g?1 at the current density of 150 mA g?1, and a high rate capability of 85 mAh g?1 even at a high current density of 3 A g?1. Moreover, outstanding capacity retention of 77% after 1000 cycles is achieved. Ex situ characterizations verify that the excellent electrochemical performance of NaVO3 is attributed to superior structural stability and electrochemical reversibility upon long-term cycling. Furthermore, the lithium ion de/intercalation mechanism for NaVO3 is also revealed involving one electron transfer reaction between V5+ and V4+ redox couple. Considering the low cost and material sustainability as well as the outstanding electrochemical performances, we believe that NaVO3 is a highly promising cathode material for lithium rechargeable batteries and our findings may help to pave the way for developing vanadium-based layered structure materials for high-performance alkali and alkaline-earth ion batteries.
Na1/2Bi1/2VO3 and K1/2Bi1/2VO3: New Lead-Free Tetragonal Perovskites with Moderate c/ a Ratios
Yamamoto, Hajime,Ogata, Takahiro,Patel, Satyanarayan,Koruza, Jurij,R?del, Jürgen,Paul, Atanu,Saha-Dasgupta, Tanusri,Sakai, Yuki,Itoh, Mitsuru,Azuma, Masaki
, p. 6728 - 6736 (2018/10/02)
New lead-free tetragonal perovskites Na1/2Bi1/2VO3 and K1/2Bi1/2VO3 were synthesized under high pressure (6 GPa) and high temperature (1473 K), based on the design of materials optimizing the lone pair effect of the A-site ion and utilizing the Jahn-Teller effect in the B-site V4+. The magnitudes of the c/a ratio and spontaneous polarization, PS, were 1.085 and 108 μC/cm2, respectively (73 μC/cm2 by the point charge model), for Na1/2Bi1/2VO3 and 1.054 and 92 μC/cm2, respectively (56 μC/cm2 by the point charge model), for K1/2Bi1/2VO3, which are comparable to the well-known lead-based ferroelectric PbTiO3. This approach can guide the design of new lead-free ferroelectric and piezoelectric materials.
Vanadium(v) oxoanions in basic water solution: A simple oxidative system for the one pot selective conversion of l-proline to pyrroline-2-carboxylate
Biancalana, Lorenzo,Tuci, Giada,Piccinelli, Fabio,Marchetti, Fabio,Bortoluzzi, Marco,Pampaloni, Guido
, p. 15059 - 15069 (2017/11/14)
The unprecedented, direct chemical oxidation of l-proline to pyrroline-2-carboxylate was achieved in water (pH 9-10) by means of NH4VO3/NH3 or V2O5/MOH (K = Na, K), and the anion was fully characterized as ammonium or alkaline metal salts. Quantitative yield and higher atom economy performance were achieved with the latter system, the alkaline salts being more stable than the ammonium one. Different mixed valence V(iv)/V(v) compounds precipitated from the reaction mixtures depending on the nature of the employed base. A possible reaction mechanism is proposed according to DFT calculations. The analogous reaction of trans-4-hydroxy-l-proline with NH4VO3/NH3 afforded pyrrole-2-carboxylic acid in 81% yield, while sarcosine underwent prevalent decomposition under similar experimental conditions. Instead, no reaction was observed with primary (glycine, l-alanine, l-phenylalanine) and tertiary α-amino acids (N,N-dimethyl-l-phenylalanine, N,N-dimethylglycine).
Bovine serum albumin binding, antioxidant and anticancer properties of an oxidovanadium(IV) complex with luteolin
Naso, Luciana G.,Lezama, Luis,Valcarcel, María,Salado, Clarisa,Villacé, Patricia,Kortazar, Danel,Ferrer, Evelina G.,Williams, Patricia A.M.
, p. 80 - 93 (2016/02/05)
Chemotherapy using metal coordination compounds for cancer treatment is the work of the ongoing research. Continuing our research on the improvement of the anticancer activity of natural flavonoids by metal complexation, a coordination compound of the natural antioxidant flavone luteolin (lut) and the oxidovanadium(IV) cation has been synthesized and characterized. Using different physicochemical measurements some structural aspects of [VO(lut)(H2O)2]Na·3H2O (VOlut) were determined. The metal coordinated to two cis-deprotonated oxygen atoms (ArO-) of the ligand and two H2O molecules. Magnetic measurements in solid state indicated the presence of an effective exchange pathway between adjacent vanadium ions. VOlut improved the antioxidant capacity of luteolin only against hydroxyl radical. The antitumoral effects were evaluated on MDAMB231 breast cancer and A549 lung cancer cell lines. VOlut exhibited higher viability inhibition (IC50 = 17 μM) than the ligand on MDAMB231 cells but they have the same behavior on A549 cells (ca. IC50 = 60 μM). At least oxidative stress processes were active during cancer cell-killing. When metals chelated through the carbonyl group and one adjacent OH group of the flavonoid an effective improvement of the biological properties has been observed. In VOlut the different coordination may be the cause of the small improvement of some of the tested properties of the flavonoid. Luteolin and VOlut could be distributed and transported in vivo. Luteolin interacted in the microenvironment of the tryptophan group of the serum binding protein, BSA, by means of electrostatic forces and its complex bind the protein by H bonding and van der Waals interactions.
Multi-component synthesis of highly substituted imidazoles catalyzed by nanorod vanadatesulfuric acid
Nasr-Esfahani, Masoud,Montazerozohori, Morteza,Abdizadeh, Tooba
, p. 1491 - 1499 (2015/09/15)
Nanorod vanadatesulfuric acid (VSA NRs), as a recyclable and eco-benign catalyst, was used for one-pot synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles using aldehydes, benzil, benzoin or 9,10-phenanthrenequinone and ammonium acetate or aniline under solvent-free conditions providing high to excellent yields. VSA is easily prepared by a simple reaction of chlorosulfonic acid and sodium metavanadate in high purity. As compared with the conventional procedures, the present protocol offers several advantages such as simplicity of procedure, short reaction time, high yields, easy workup, recoverability and reusability of the catalyst and simple purification of the products.
Chemical sodiation of V2O5by Na2S
Haberkorn, Robert,Bauer, Jessica,Kickelbick, Guido
, p. 3197 - 3202 (2015/02/19)
Chemical sodiation of V2O5 at low temperatures allows to synthesize NaxV2O5 with 0≤ x≤ 1, while classic high temperature syntheses yield in either x≤ 0.02 (α-phase) or 0.7≤ x (α′-phase), or other phases (β-phase, δ-phase) or mixtures thereof. A suspension of V2O5 in acetonitrile and Na2S as sodiation agent were used. The maximum amount of sodiation was obtained by using an excess of Na2S, refluxing the acetonitrile during the reaction, and precedent ball milling of the V2O5. If only low amounts of Na2S were used as starting material, a mixture of fractions of NaxV2O5with different values of x was obtained. All these fractions belong to the α- or α′-phase, space group Pmmn.
