MATERIALS LETTERS
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2024
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IF 2.7
Yuhui Chen,Zhenhua Hao,Rulong Ma,Pei Wang,Yongchun Shu,Jilin He
Ultrafine tungsten (W) powder was prepared by a non-contact carbon reduction followed by hydrogen reduction method. In this process, WO 3 and activated carbon were separated by a porous plate and the reduction of tungsten oxide was achieved by carbon atoms diffusion at high temperature. This method can stably prepare violet tungsten oxide powder with low carbon content (194 ppm) using activated carbon as a reducing agent. It avoids the problem that the high residual carbon in reduction products in traditional carbon reduction experiment. Then, ultrafine tungsten powder with an average particle size of less than 100 nm was prepared by hydrogen reduction of violet tungsten oxide.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
POWDER METALLURGY AND METAL CERAMICS
·
2022
·Vol. 61
·期 3
·221-229
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IF 0.913
Liang Dong,Xiong Sang,Zhang Xiaojuan,Lin Qing
Tungsten oxide is widely used in the photolysis of water for hydrogen production, photocatalysis, photoelectric conversion, and electrochromism. Eu 3+ doped tungsten trioxide nanoparticles were prepared by hydrothermal method with the addition of sodium tungstate (NaWO 4 · 2H 2 O). Two different samples were obtained at the temperature set at 160 and 180°C. The third sample obtained from ammonium paratungstate ((NH 4 ) 10 H 2 (W 2 O 7 ) 6 ) was used at the temperature of 160°C. The samples’ morphology, structure, and optical performance were then observed and analyzed. The results show that a rod-like structure of WO 3 : Eu 3+ nanoparticle with a monoclinic crystal system can be successfully generated using sodium tungstate. A spherical structure of WO 3 : Eu 3+ nanoparticle with a triclinic crystal system was prepared using ammonium paratungstate. The finished sample with ammonium paratungstate at a reaction temperature of 160°C has the smallest grain average size of 45.98 nm and Eu 3+ ions successfully doped. Under the excitation of different wavelengths, the three samples demonstrate pronounced emission peaks at around 615 nm, corresponding to the 5D 0 → 7F 2 electronic transition of Eu 3+ . Using ammonium paratungstate as the tungsten source, the prepared WO 3 : Eu 3+ nanoparticle at 160°C has the highest luminous intensity. The luminescence intensity of the prepared WO 3 : Eu 3+ nanoparticle from ammonium paratungstate as a tungsten source is higher than the other two samples obtained from sodium tungstate as a tungsten source at two temperatures. However, the three samples with excitation wavelength λ = 254 nm were monitored at the wavelength of 615 nm. All three samples exhibited the most substantial excitation peaks at about 508 nm, which belonged to the electron transition in 4f of Eu 3+ .
研究领域:
材料科学
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光学
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DOI
高影响因子
MATERIALS LETTERS
·
2018
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IF 2.687
Jianyin Zhang,Rongli Li
Hexagonal tungsten trioxide nanoparticles were prepared using ammonium metatungstate hydrate as the precursor by a facile molten salt method. The as-prepared samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectropy, Brunauer-Emmett-Teller, Scanning electron microscope and Transmission electron microscope. When applied for lithium-ion battery anode, it delivers 320 mAh g −1 delithiation capacities at current density of 100 mA g −1 after 130 discharge-charge cycles. The results indicate that tungsten trioxide prepared by molten salt method would be a promising anode for Lithium-ion batteries.
研究领域:
材料科学
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能源存储
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DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2015
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IF 7.435
Jian-Ping Zou,Jun Ma,Jin-Ming Luo,Jian Yu,Junkai He,Yongtao Meng,Zhu Luo,Shao-Kui Bao,Hui-Long Liu,Sheng-Lian Luo,Xu-Biao Luo,Tong-Cai Chen,Steven L. Suib
Novel heterostructured composite of few layered WS 2 -Bi 2 WO 6 /Bi 3.84 W 0.16 O 6.24 has been synthesized via a facile hydrothermal method for the first time. The obtained catalysts were systematically characterized by X-ray diffraction (XRD), SEM, TEM, EDS, Raman spectroscopy, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) to certify the existence of WS 2 with a few-layered structure among the heterostructured composite, and to illuminate the relationship of its performance and the structural features. Among the as-prepared catalysts, the few layered WS 2 -Bi 2 WO 6 /Bi 3.84 W 0.16 O 6.24 composite show the best photocatalytic degradation of RhB under visible light irradiation. The enhanced photocatalytic performance of the heterostructured few layered WS 2 -Bi 2 WO 6 /Bi 3.84 W 0.16 O 6.24 composite is attributed to the two-dimensional structure of WS 2 with special properties and the matching energy band structure for efficient separation of photogenerated electron–hole pairs. The formation mechanism and photocatalytic mechanism were proposed. The present work firstly combined layered TMDs with composites to prepare ternary heterostructured catalysts, which provide new ideas for obtaining novel layered TMDs-based composites with excellent performance.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
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2018
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IF 3.398
Ming Li,Xiaoli Xi,Zuoren Nie,Liwen Ma,Qingqing Liu
The recycling of WC–Co hard metal scraps has been taken into consideration in the literature, due to the release of toxic substances and long recovery process. In this study, the recovery of tungsten process, based on the molten salt electrolysis treatment of WC–Co hard metal scraps, was developed. The anode polarization curves were applied to investigate the dissolution of the WC–Co hard metal scrap. Then, the electrochemical behavior of tungsten and cobalt ions dissolved from WC–Co scrap anode, was studied by cyclic voltammetry (CV) and square wave voltammetry (SWV). The results demonstrated that the reduction of tungsten and cobalt ions occurred through a one-step process involving the transfer of two electrons. This process was achieved by the diffusion of tungsten and cobalt ions in the melts. Finally, the parameters, such as the electrolysis current, the electrolysis duration and temperatures, were applied to analyze the effect of different electrolysis conditions on the composition of recycled products. The results demonstrated that the electrolysis current and the electrolysis temperature, compared to electrolysis duration, have significant effects on the selectivity of tungsten recycling. Furthermore, the analysis of cathode products demonstrated that a tungsten powder of approximately 500 nm could be selectively recovered from WC–Co hard metal scrap with the electrolysis condition of 60 mA for 4 h at 1073 K in NaF–KF molten salt.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
ACS Applied Materials & Interfaces
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2016
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IF 7.145
Lun Yang,Xiaobin Zhu,Shijie Xiong,Xinglong Wu,Yun Shan,Paul K. Chu
Tungsten trioxide dihydrate (WO3·2H2O) nanoplates are prepared by in situ anodic oxidation of tungsten disulfide (WS2) film on carbon fiber paper (CFP). The WO3·2H2O/WS2 hybrid catalyst exhibits excellent synergistic effects which facilitate the kinetics of the hydrogen evolution reaction (HER). The electrochromatic effect takes place via hydrogen intercalation into WO3·2H2O. This process is accelerated by the desirable proton diffusion coefficient in the layered WO3·2H2O. Hydrogen spillover from WO3·2H2O to WS2 occurs via atomic polarization caused by the electric field of the charges on the planar defect or edge active sites of WS2. The optimized hybrid catalyst presents a geometrical current density of 100 mA cm–2 at 152 mV overpotential with a Tafel slope of ∼54 mV per decade, making the materials one of the most active nonprecious metal HER catalysts.
研究领域:
材料科学
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催化化学
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产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
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IF 7.632
Zhihua Li,Jin Lu,Shengxi Wu,Guiqing Zhang,Wenjuan Guan,Li Zeng,Qinggang Li,Zuoying Cao
Complete separation of tungsten from molybdenum has long been a technical bottleneck in the metallurgy of molybdenum because no theoretical basis exists for the complexation and extraction mechanism of tungsten and molybdenum from aqueous solution. To completely separate tungsten from ammonium molybdate, the speciation and equilibria of compounds in H+–WO42–, H+–MoO42–, and H+–MoO42––WO42– aqueous systems were systematically investigated. With decreasing pH, the stability of polymerized tungsten species in H+–MoO42––WO42– decreased in the following order: MoW6O246– > Mo2W5O246– > Mo3W4O246– > Mo4W3O246– > Mo5W2O246– > Mo6WO246–, and as the W(VI) concentration decreased, low-molecular-weight species increasingly dominated the W(VI) and Mo(VI) polymerization products. The extraction characteristics of tungsten and molybdenum with primary N1923 were consistent with their polymerization behaviors. Methods based on the thermodynamic theory and the aforementioned extraction mechanism were used to completely separate W(VI) from ammonium molybdate solution containing different grades of W(VI) (trace to macro). Ammonium molybdate solution with a 2.25 × 10–7 W/Mo mass ratio met the purity requirement for ultra-high-purity ammonium molybdate (99.999%, 5N) and further molybdenum products. During extraction, the equilibrium pH was controlled by extractant acidification using inexpensive mineral acids. The proposed process is cheap and sustainable and has a broad spectrum and high efficiency; these advantages are expected to provide economic and environmental benefits.
研究领域:
冶金学
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环境科学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2024
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IF 5.8
Xi Wang,Zelai Cheng,Yulan Jing,Xiaoli Tang,Hua Su
To meet the demands of the growing field of electronic communications, LiInW 2 O 8 ceramics with low dielectric loss (high Q×f ) and low dielectric constant ( ε r ) are prepared by a solid phase reaction method. X-ray diffractometry reveals a scheelite single-phase structure for the prepared ceramics. Compared with the standard LiInW 2 O 8 , the as-prepared LiInW 2 O 8 has a higher relative diffraction intensity for the (200) crystal plane, indicating an anisotropic growth phenomenon in the present case. Raman spectroscopy and calculations of the P-V-L complex chemical bonding theory show that W-O bonding is a key factor affecting the dielectric properties of LiInW 2 O 8 ceramics. Furthermore, excellent microwave dielectric properties with ε r ≈ 14.2, Q×f ≈ 63000 GHz, and τ f ≈ −28 ppm/℃ are obtained by sintering the ceramic at 1025°C.
研究领域:
材料科学
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电子通信
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
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IF 7.632
Naixu Li,Xu Liu,Jiancheng Zhou,Quanhong Ma,Maochang Liu,Wenshuai Chen
Direct conversion of cellulose into ethylene glycol is a promising route for transforming sustainable biomass resources into high-value chemicals. Although numerous attempts have been made to exploit tungsten-based hydrogenolysis catalysts in the catalytic conversion of cellulose to ethylene glycol for high conversion rate and selectivity, maintaining catalyst stability remains challenging. Herein, we have developed a Ni–W/M catalyst with good catalytic performance and stability, which were obtained by calcining Ni–W/MIL-125(Ti) precursor. The synthesized catalyst showed good cellulose conversion rate (100%) and ethylene glycol yield (68.7%). The tungsten species was linked to the TiO2 support by Ti–O–W bonds to reduce loss of the active tungsten component. The formation of new bonds enhanced the catalyst stability and durability, enabling the catalysts to retain high catalytic activity during recycling.
研究领域:
化学工程
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可再生资源利用
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产品关联
DOI
高影响因子
Micro & Nano Letters
·
2020
·Vol. 15
·期 1
·58-63
·
IF 0.975
Yu She,Yufu Zhu,Lei Zhou,Yuanmi Yuan,Jing Hao,Qingsong Jiang
In this study, tungsten oxide microstructures/nanostructures with different morphologies were prepared by the hydrothermal synthesis methods. The morphologies and structures of the obtained products were characterised by field-emission scanning electron microscopy and X-ray diffraction. The photocatalytic properties of tungsten oxide microstructures/nanostructures were characterised by the degradation of rhodamine B solution. The results indicate that tungsten oxide microspheres prepared by using tungstic acid and hydrogen peroxide solution as raw materials show the highest photocatalytic activity. By changing the concentration of tungstic acid used in the synthesis process, the morphologies of tungsten oxide microspheres can be controlled. The influences of the amount of chemical reagent addition on its morphology and catalytic properties were discussed. In order to further improve the photocatalytic activity of the samples, Ag nanoparticles were loaded on the obtained tungsten oxide microspheres. The photocatalytic experiment results indicate that the photocatalytic performance of tungsten oxide was improved by Ag loading. The results indicate that Ag-loaded tungsten oxide microspheres are favourable for their photocatalytic applications.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Jia-Yi Liu,Dayong Zhang,Hao Zhou,Xianliang Yi,Yang Liu
A series of pyrolusite-manganite composites with five levels of phosphotungstic acid additions (HPWxMn, x indicating the added mass of phosphotungstic acid) were applied in the catalytic oxidation of 330–350 mg/m 3 formaldehyde under ambient conditions. Different techniques were used to characterize the pristine composite and the best-performed HPW0.2Mn catalyst. Compared to the effects of hydrogen (replacing a small part of structural K + ions) and phosphorus (not detected in the HPW0.2Mn catalyst) elements in phosphotungstic acid, the doping of tungsten would prefer to occur via forming W-O-Mn species, which significantly altered the crystallite growth and induced numerous defects. As to formaldehyde degradation, the best 91% conversion and 72% CO 2 yield were achieved on HPW0.2Mn. The uniqueness of tungsten doping on boosting formaldehyde oxidation was expounded from the angles of intimate elemental interaction (XPS), redox behavior and molecular O 2 activation (CO-TPR, UV-Vis DRS and O 2 -TPD). The incorporation of tungsten led to higher surface Mn 3+ concentration, higher content of surface oxygen vacancies , better low-temperature reducibility and abounding chemically adsorbed oxygen species (They were proposed to be the dominant oxidants for formaldehyde oxidation in this study), which were well correlated with the sequence of catalytic activity. Finally, possible reaction pathways were examined by coupling the characterizations of used catalysts.
研究领域:
环境科学
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催化材料科学
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产品关联
DOI
高影响因子
Additive Manufacturing
·
2020
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IF 7.002
Zhangping Hu,Yanan Zhao,Kai Guan,Zumin Wang,Zongqing Ma
The microstructure and cracking behavior of pure tungsten and micron- and nanosized Y 2 O 3 dispersion strengthened tungsten fabricated by selective laser melting are comparatively studied in this work. The pure tungsten with high density (98.3 ± 0.3 %) is successfully fabricated by optimizing processing parameters, but there are still a few microcracks. The cracking mechanism of pure tungsten is attributed to the segregation of tungsten oxide impurities at the grain boundaries and the formation of high-angle grain boundaries. The agglomeration of Y 2 O 3 occurs only in the tungsten with the addition of micron-Y 2 O 3 while not in the tungsten with the addition of nanosized Y 2 O 3 . The addition of Y 2 O 3 can reduce cracks due to the formation of a large number of low-angle twisted tungsten grains. The cracking mechanism of pure tungsten and the inhibition of cracking by the addition of Y 2 O 3 proposed in this work are of great significance for the SLM manufacture of high-performance and crack-free tungsten-based alloys. Our work may also provide relevant strategy for the suppression of crack in other alloys with high melting point by SLM.
研究领域:
材料科学
·
制造工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）