Applied Catalysis O: Open
·
2024
·
IF 0
Jiayuan Nie,Pengyu Yin,Qiusheng Yang,Zhihui Li,Yanji Wang,Xiaoshu Ding,Dongsheng Zhang
In this study, metallic vanadium was used as catalysts for direct amination of toluene with hydroxylamine to produce toluidine under mild conditions. High toluene conversion and toluidine selectivity were obtained, corresponding to 87.62% and 96.45% respectively. Additionally, thermodynamic and kinetic calculations were carried out. It was concluded that the reaction was dominated by kinetics, with the distribution of three products being para > ortho > meta. The computational and experimental results indicated that the amination process involves an amino radical mechanism.
研究领域:
有机化学
·
催化化学
·
反应工程
✓ 已验证
DOI
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Xuansheng Wang,Muzi Liu,Tian Tian,Fang Liu,Jiali Wang,Jinping Li,Guang Liu
MgH₂ is recognized as one of the most promising solid hydrogen storage materials; however, its practical application is confined by sluggish kinetics and stable thermodynamics. In this study, fibrous VNbO₅ was synthesized via electrospinning and subsequently introduced into MgH₂ through ball milling technology to enhance hydrogen storage properties. The addition of 7 wt% VNbO₅ give rise to the obvious decline in the initial dehydrogenation temperature of MgH₂, from 322.2 °C to 200.2 °C. At 300 °C, the modified composite exhibited rapid dehydrogenation, releasing approximately 6.43 wt% hydrogen within 8.1 min. Moreover, the fully dehydrogenated sample demonstrated the ability to absorb hydrogen at room temperature and absorbed 6 wt% H₂ at 200 °C within 16 s. The desorption activation energy of the MgH₂-7 wt% VNbO₅ composite was determined to be 75.32 ± 1.44 kJ/mol, representing an approximate 48.1% reduction compared to the 145.25 ± 2.14 kJ/mol of pure MgH₂. Furthermore, the system possessed remarkable cyclic stability, retaining 95.5% of hydrogen storage amount after 20 cycles. During the reaction process, VNbO₅ decomposed into low-valence state active catalytic species, including Nb₂O₅, NbO, Nb, VO₂, and V. The in-situ generation of this multi-element, multi-valence chemical environment synergistically enhanced hydrogen storage performance of MgH₂.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2017
·
IF 3.359
Ying Zhang,Ting-An Zhang,David Dreisinger,Weihua Zhou,Feng Xie,Guozhi Lv,Weiguang Zhang
In the current study, a novel chelating extractant Mextral 973H was employed to selectively extract V(V) from a low pH sulfuric acid solution containing high concentration of Fe (Ш). The extraction of V(V) is strongly dependent on solution pH, and the separation coefficient (β (V/Fe) ) between V(V) and Fe(Ш) can be greater than 720 when the solution pH < 0.5. A cation exchange between H and VO 2 + was proposed as the main extraction mechanism at pH < 1.5, while at pH > 1.5, a solvating reaction between the extractant and metal-oxo cluster anions took place. The effects of solution pH, acid medium types, contacting time and temperatures on the extraction and separation of V have been discussed. FT-IR and 1 HNMR were applied to confirm the extraction mechanism and also the degradation behavior of Mextral 973H in some extreme conditions. The loaded vanadium was effectively stripped using a diluted 0.2 M Na 2 CO 3 solution and a total stripping extent of 97% was achieved. The extraction process by Mextral 973H was finally simulated using Aspen Plus simulator comparing to traditional process, the results obtained were in good recovery efficiency and with the advantage of acid and alkali saving.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
Catalysts
·
2016
·Vol. 6
·期 5
·74
·
IF 2.964
Yongli Dong,Xiaoyu Niu,Weina Song,Dong Wang,Liqiang Chen,Fulong Yuan,Yujun Zhu
The vanadium oxide/reduced graphene oxide (VOx/RGO) composites have been prepared by a simple solvothermal method with the assistance of cationic surfactant cetyltrimethylammonium bromide (CTAB). The microstructure and morphology of the resultant VOx/RGO composites have been well characterized. The VOxnanoparticles are highly dispersed on the RGO sheets with a particle size of about 25 nm. When used as hydroxylation catalysts, the VOx/RGO composites are more efficient than individual RGO and vanadium oxide catalysts. The enhanced catalytic performance may be related to not only the well dispersed VOxactive species, but also the hydrophobic surface and huge π-electron system of RGO for the adsorption and activation of benzene. In addition, the effects of calcination conditions on the microstructure and catalytic properties of VOx/RGO composites have also been investigated. The uniform VOxnanoparticles on the separated RGO sheets show highly efficient catalytic performance, while the formation of aggregated HxV2O5and bulk V2O5species along with the destruction of RGO sheets are poor for the hydroxylation of benzene. Up to 17.4% yield of phenol is achieved under the optimized catalytic reaction conditions.Keywords:vanadium oxide;reduced graphene oxide;benzene;hydroxylation;phenol
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Peiwen Liu,Yannan Zhang,Peng Dong,Yingjie Zhang,Qi Meng,Siyuan Zhou,Xuan Yang,Mingyu Zhang,Xi Yang
Direct regeneration has been widely applied in recovery of LiFePO 4 batteries. However, excess residual carbon and inherent low electronic and ionic conductivity of spent LiFePO 4 /C cathode materials lead to the reduction of electrochemical performance. Herein, a facile and simple regeneration process of pre-oxidation and vanadium doping is developed to regenerate LiFePO 4 /C cathode materials . Pre-oxidation was applied to remove excess carbon at 500 °C for 3 h in air. Vanadium doping was applied to improve electronic and ionic conductivity of regenerated cathode materials. Among the regenerated cathode materials, the 3 mol% V doped sample possesses discharge capacity of 134.3 mAh/g after 200 cycle at 1C with the discharge capacity retention of 99.1%. At 2, 5, 10C, the discharge capacities are 134, 124.1, 111.5 mAh/g, respectively. The vanadium doping regeneration process with oxidation pre-oxidation is simple, and feasible to be applied in the recovery of spent LiFePO 4 cathode materials.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 40
·15000-15007
·
IF 8.067
Han Zhang,Wenqing Zhu,Lu Huang,Chen Yi,Ruilin Chen,Yipeng Chen,Jun Li
The hole-injection layer (HIL) plays a critical role in the efficiency and stability of organic light-emitting diodes (OLEDs). However, inorganic HIL materials, such as transition metal oxides (TMOs), usually suffer the problems of low conductivity and mismatched work function at ITO/hole-transport layer (HTL) interfaces, which limits the hole-injection in OLEDs. In this paper, a gold (Au) and lithium (Li) co-doping strategy has been employed to fabricate a vanadium oxide (VOx) HIL through solution processing at low temperature for improving device performance. Compared to non-doped VOx and Au-doped VOx films, co-doping with an optimal molar ratio of Au and Li endows the VOx films with both higher electrical conductivity and proper work function matching with the ITO anode and HTL, which leads to efficient hole-injection and improved carrier balance in the device with the Au and Li co-doped VOx (Au,Li:VOx) HIL. As a result, the device with the Au,Li:VOx HIL shows a peak power efficiency of 50.2 lm W−1 and a maximum external quantum efficiency (EQE) of 19.9%, which are superior to those of the counterpart with the VOx HIL (34.4 lm W−1 and 18.1%). Meanwhile, the device shows distinguished stability. This work indicates that Au and Li co-doping is an effective method to obtain an efficient VOx HIL with excellent hole-injection ability, which provides a promising avenue to enhance OLED performance.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
e-Journal of Surface Science and Nanotechnology
·
2012
·
IF 0
L. Z. Pei,Y. Q. Pei,Y. K. Xie,Z. Y. Cai
Calcium sulfate and calcium vanadate nanostructures have been synthesized by a hydrothermal route using calcium sulfate and sodium vanadate as the raw materials. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectrum. XRD and SEM observation show that the products are composed of calcium sulfate nanosheets with orhorhombic CaSO4 phase and calcium vanadate nanorods with tetragonal CaV4O9 phase. The size and morphology of the products can be adjusted by controlling the hydrothermal conditions and raw materials. The size of calcium sulfate nanosheets and calcium vanadate nanorods increases obviously with increasing the hydrothermal temperature and reaction time. The formation process of the calcium sulfate and calcium vanadate nanostructures is also discussed. [DOI: 10.1380/ejssnt.2012.585]
研究领域:
无机化学
·
材料科学
·
纳米技术
·
固体化学
·
功能材料
✓ 已验证
DOI
CHINESE JOURNAL OF CATALYSIS
·
2016
·
IF 2.628
Cheng Wang,Liya Hu,Meiyin Wang,Yuanhang Ren,Bin Yue,Heyong He
A series of graphitic carbon nitride supported vanadium catalysts ( x V/g-C 3 N 4 ) with different vanadium contents ( x /%) were prepared by impregnation. XRD, FT-IR, TEM, TG-DTG, nitrogen adsorption and XPS characterizations were conducted which revealed a strong interaction between the vanadium species and g-C 3 N 4 support. 8V/g-C 3 N 4 exhibited the highest activity and showed stable recyclability in the benzene hydroxylation reaction with a benzene conversion of 24.6% and phenol selectivity of 99.2% under the optimized conditions. The excellent catalytic performance of x V/g-C 3 N 4 was due to the integration of vanadium species with high catalytic activity and the g-C 3 N 4 support in their interaction with the benzene substrate
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Qianghong Wu,Youzhi Wu,Fen Ran
The harm of vanadium and nano-plastic pollution to organisms and the destruction of ecological environment are increasingly concerned by the world. However, due to the multiple valence states of vanadium and the high temperature cracking of nano-plastics, which can provide additional capacity and effectively improve the structural morphology and graphitization degree of materials, so it has great development potential in energy storage field. In this work, Pleurotus ostreatus is used to absorb both vanadium and nano-plastics, including nano-PS, nano-PS-NH 2 , and nano-PS-COOH, which are used to regulate the absorption of vanadium ions by Pleurotus ostreatus. Vanadium ions, nano-plastics, and their complexes can coordinate and decompose with various polymers of Pleurotus ostreatus. The biochar-vanadium composites prepared by this method have high specific surface area, high graphitization degree, rich hierarchical porous structure, and N, O, S, and other heteroatoms, showing good spatial confinement effect and heteroatom anchoring effect. The series of optimization processes make the electrode materials exhibit excellent electrochemical performance in supercapacitors. When the current density is 0.5 A·g −1 , the specific capacitance reaches 582.6 F·g −1 ; at 50 A·g −1 , the specific capacitance is still as high as 325 F·g −1 . After 30, 000 cycles, the specific capacitance can still reach 361.6 F·g −1 at 2 A·g −1 . The Coulomb efficiency is about 99 %. In addition, the electrode material can also be applied in zinc-ion batteries.
研究领域:
环境科学
·
材料科学
·
能源存储
·
生物技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Sustainable Metallurgy
·
2024
·Vol. 10
·期 4
·2630-2645
·
IF 2.5
Wu Zi-wang,Wang Lai-xin,Li Jing-wei,Lin Yin-he,Wang Da-long,Zhang Lin,Fan Yu-hang,Tang Wen-ming,Chen Hong-sheng
Vanadium titanomagnetite (VTM) is a complex polymetallic symbiotic mineral dominated by iron, titanium, and vanadium. Iron extraction from VTM is an issue for the utilization of Vanadium titanomagnetite concentrate. In this work, flotation method combined with magnetic sorting was proposed to separate and recover the iron resources from VTM. The reverse cationic flotation of iron ore in VTM was carried out with polyetheramine (PEA, molecular weight of 2000) as collector, and the differences of iron grade and recovery in VTM with different particle sizes were studied. The magnetic separation result shows that the iron grade of the magnetic part is 28.38% with the particle size 100–74 μm, which is 10% higher than the iron grade of the raw ore. The flotation results of magnetic separation products show that PEA-2000 can effectively separate and recover iron from VTM. The iron grade of the magnetic part is increased to 47.27% after flotation process at particle size 100–74 μm, pulp pH 4, PEA-2000 concentration 1 × 10 −4 mol/L, and pulp concentration 10 g/L. The mechanism of flotation separation of Fe from VTM by PEA-2000 was analyzed by zeta potential test, FT-IR test, and XPS test. PEA is adsorbed on the surface of silicate in VTM by electrostatic adsorption and hydrogen bond adsorption, and the iron phase minerals are mutually repulsive, which realizes the separation of iron. The model of iron separation by flotation of PEA-2000 was established. Graphical
研究领域:
矿物加工工程
·
材料科学与工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Huayi Tan,Bingqiang Fan,Shili Zheng,Hedong Zhang,Yang Zhang
Molybdenum (Mo) and vanadium (V) are both important strategic metals. Due to their similar physicochemical properties, it is always a challenge to realize their deep separation from a solution. However, based on the valence difference of Mo and V, this task can be achieved by the selective complexation precipitation of hexamethylenetetramine (HMT). In this study, through precipitation behavior studies in the single metal species solutions and the mixed species solutions of Mo and V in different chemical valence states, the complexation precipitation separation system of V and Mo was constructed. As a result, in the single metal species solution, the precipitation depths of Mo(V), Mo(VI) and V(V)) reached 96.83% 98.77% and 99% under the best conditions, respectively, while V(IV) remained in the solution. The results of the mixed-species complexation precipitation experiments revealed the most efficient selective separation scheme by HMT. Furthermore, combined with the characterization of the complexation precipitates of HMT with the single species of Mo(V), Mo(VI) and V(V), the mechanisms of the complexation reactions were elucidated. In particular, due to the different ion species of Mo caused by the different valence states, the complexation precipitation mechanisms of Mo(V) were different from those of Mo(VI). Finally, the differences in the mechanisms of Mo(V), Mo(VI) and V(V) complexation were also presented in their kinetics, and the reaction constants and activation energies were calculated by first-order kinetics. This study may provide further insight into the selective complexation separation of Mo and V.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 38
·18090-18104
·
IF 3.5
Gong Xin,Luo Pan,Wang Kaiming,Yang Yang,Zhu Huacheng,Yan Liping,Zhou Yanping
Vanadium nitride (VN) has gained much attention for microwave absorption due to its high electrical conductivity and easily tunable microscopic morphologies. However, its microwave dissipation ability is yet to be enhanced. In this work, vanadium nitride with 3D/2D hierarchical microflower structure is successfully fabricated via a rapid microwave hydrothermal method followed by a nitridation process enabled by the in-situ upstream thermal decomposition of melamine. By incorporating with N-doped graphene (N-rGO) in different ratios, the proportion of conduction loss and relaxation polarization loss in VN/N-rGO could be tuned, yielding a minimum reflection loss of − 45.9 dB at 10.4 GHz with 5 wt% filler loading. Further, to achieve optimal ultra-broadband microwave absorption, a rational double-layer absorber is constructed by attaching the N-rGO layer with lower normalized impedance but high dissipation capability under the VN/N-rGO layer with excessively high normalized impedance, delivering a maximum effective absorption bandwidth of 10.3 GHz at a total thickness of 4.9 mm. Impedance matching and power loss density distribution analysis are done to illustrate the working mechanism of the double-layer structure. Graphical abstract
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）