Nanomaterials
·
2024
·Vol. 14
·期 8
·722
·
IF 4.4
Zhengtang Cai,Kaipeng Zheng,Chun Ma,Yu Fang,Yuyang Ma,Qinglin Deng,Han Li
Compared to SnTe and PbTe base materials, the GeTe matrix exhibits a relatively high Seebeck coefficient and power factor but has garnered significant attention due to its poor thermal transport performance and environmental characteristics. As a typical p-type IV–VI group thermoelectric material, W-doped GeTe material can bring additional enhancement to thermoelectric performance. In this study, the introduction of W, Ge1−xWxTe (x= 0, 0.002, 0.005, 0.007, 0.01, 0.03) resulted in the presence of high-valence state atoms, providing additional charge carriers, thereby elevating the material’s power factor to a maximum PFpeakof approximately 43 μW cm−1K−2, while slightly optimizing the Seebeck coefficient of the solid solution. Moreover, W doping can induce defects and promote slight rhombohedral distortion in the crystal structure of GeTe, further reducing the lattice thermal conductivityκlatto as low as approximately 0.14 W m−1K−1(x= 0.002 at 673 K), optimizing it to approximately 85% compared to the GeTe matrix. This led to the formation of a p-type multicomponent composite thermoelectric material with ultra-low thermal conductivity. Ultimately, W doping achieves the comprehensive enhancement of the thermoelectric performance of GeTe base materials, with the peak ZT value of sample Ge0.995W0.005Te reaching approximately 0.99 at 673 K, and the average ZT optimized to 0.76 in the high-temperature range of 573–723 K, representing an increase of approximately 17% compared to pristine GeTe within the same temperature range.
研究领域:
材料科学
·
能源材料
·
热电材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
KEY ENGINEERING MATERIALS
·
2016
·
IF 0
Jian Wu,Cheng Zhang,Jin Feng Xia,Dan Yu Jiang
In this study, Yttria-stabilized zirconia (YSZ) electrochemical sensors attached with the WS2 sensing electrode (SE) were fabricated and examined for NO2 sensing properties. Due to its internal stratiform structure, surface and edge of the lamella have high chemical activity, WS2 was used as a kind of highly efficient catalyst. WS2 was partial oxidated to WO3 at 400°C, and with the increment of temperature, oxidation will accelerate. The ΔEMF to 500 ppm NO2 was as high as 125mv at 400°C, while the value of WO3-based sensor was as small as 10 mv in the same condition. These WS2-attached devices gave a linear correlation between EMF and the logarithm of NO2 concentration from 30 to 500 ppm in the temperature range 350–500°C. The response time of the device is about 1 min at 400°C.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
HYDROMETALLURGY
·
2020
·
IF 3.338
Jia Lipan,Zhao Zhongwei,Liu Xuheng,He Lihua
Selective precipitation is the main process used to remove molybdenum from tungstate solutions by the tungsten industry in China. The process exploits the fact that molybdenum is a sulfophile whereas tungsten is an oxyphile. First, the sulfur ions replace oxygen and convert the molybdate to thiomolybdate, then a moderate amount of additives (copper compounds) are reacted with the thiomolybdate to form complex precipitates. We call the filtered wet precipitate “molybdenum-removal sludge”. The main components of the sludge are molybdenum, copper and sulfur, infiltrated by some amount of tungsten due tomechanical entrainment. Based on the fact that copper is a typical sulfophile, it is possible that copper ions can react withthe sulfur of the thiomolybdate, thus converting it to soluble molybdate. This is actually the reverse of molybdenum sulfuration process, so we therefore call it the “reverse sulfuration process.” Based on the leaching thermodynamics and structure characteristics of this kind of sludge, a new treatment process was developed in this work. About 90% of tungsten and 15% of molybdenum were washed out with ammonia water when the pH > 9. The recovery rate of molybdenum was close to 70% when a stoichiometric amount of copper ions (with sodium hydroxide 4 mol/L) were utilized for the reverse sulfurization leaching. The leaching rate of molybdenum obtained on leaching with 2 mol/L sodium hydroxide for 120 min at 80 °C and then fixing with copper chloride was 94.4%, and 87.67% of sulfur ions were fixed in the form of an amorphous Cu S compound.
研究领域:
冶金学
·
环境科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2012
·
IF 0.826
Jianxian ZENG,Xiahui SUN,Lifeng ZHENG,Qincheng HE,Shu LI
Polyquaternium-6 (PQ6) as the water-soluble polymer was used for complexing the anion forms of tungsten (VI) before ultrafiltration. Tungsten (VI)-PQ6 complex was retained by polysulfone hollow fiber ultrafiltration membrane in the complexation-ultrafiltration process. Effects of various operating parameters such as polymer metal ratio(PMR), pH and chloride ion concentration on permeate flux ( J ) and tungsten rejection coefficient ( R ) were investigated. The integration of four experiments including concentration, decomplexation, diafiltration and reuse of regenerated polymer was carried out. In the process of concentration, J declines slowly and R is about 1 at PMR of 3 and pH of 7. Tungsten concentration in the retentate increases linearly with volume concentration factor. Tungsten is concentrated efficiently with the membrane. The concentrated retentate was used further for the decomplexation. It takes about 6 min to reach the decomplexation equilibrium at chloride ion concentration of 50 mgL −1 . The decomplexation percentage of tungsten (VI)-PQ6 complex reaches 56.1%. In the diafiltration process, tungsten (VI) can be extracted effectively by using 50 mgL −1 chloride ion solution, and the purification of the regenerated PQ6 is acceptably satisfactory. The regenerated PQ6 was used to bind tungsten (VI) at various pH values. The binding capacity of the regenerated PQ6 is close to that of fresh PQ6, and the recovery percentage of binding capacity is higher than 90%.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Yu Wang,Zhi-Bo Li,Kai-Fei Wang,Guo-Hua Zhang
Tungsten borides are special compounds with potential applications in superhard materials, anti-friction materials, and catalytic materials. In this study, a new synthetic method for tungsten boride is proposed using tungsten (W) and boron carbide (B 4 C) as raw materials. First, the boronization reaction between W and B 4 C was carried out at a high temperature; then, the boronization products were reacted with calcium to generate CaC 2 for decarburization. After acidic leaching of the CaC 2 and Ca, pure tungsten boride could be prepared. By investigating the reaction between different ratios of W and B 4 C, it was found that only pure W 2 B and WB were synthesized in the current method, and W 2 B 5 could react rapidly with Ca to form WB and CaB 6 . However, in the absence of a decarburization treatment after the boronization process, carbon-containing WB (C content = 1.2 wt%) and W 2 B 5 (C content = 3.4 wt%) could also be prepared. In addition, it was concluded that the prepared tungsten boride roughly maintained the morphology and particle size of raw W, and ultra-fine tungsten boride could be synthesized with ultra-fine W powder at a low boronization reaction temperature.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2021
·
IF 6.064
Yuxi Lu,Shuai Wang,Hong Zhong
Wolframite is often associated with calcium bearing minerals, leading to low grade, while conventional anionic collectors are hard to realize their efficient flotation separation, thus the effective structural modification of cationic collectors provides a new insight into enhancing the comprehensive development of wolframite resources. In this study, a surfactant 3-dodecyloxy propyl amidoxime (DOPA) was designed and first used as the collector in flotation separation of wolframite from fluorite and calcite. Computational calculations basically proved the correctness of predictions about the performances of DOPA. Micro-flotation tests indicated that compared to DDA and conventional anionic collector benzohydroxamic acid (BHA), DOPA possessed superior collecting ability to wolframite and excellent selectivity against fluorite and calcite at low concentration, with no frother or activator employed, which is supposed to be an efficient collector for separating wolframite from calcium bearing minerals. The separation mechanisms of DOPA between wolframite and fluorite/calcite were further probed, revealing that besides the electrostatic attraction between DOPA and wolframite, DOPA could chemisorb onto wolframite surfaces by forming five-membered ring toward the surface cation site Fe or Mn, with no significant interaction observed on fluorite/calcite surfaces, resulting to the excellent separation performance.
研究领域:
矿物加工工程
·
材料科学与工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2025
·
IF 7
Yu He,Shengwei Xin,Baoru Sun,Xuecheng Cai,Yapeng Lin,Lingwei Kong,Xun Shen,Congcong Du,Xiaoyuan Yuan,Kangkang Wen,Tongde Shen
Metals are often soft while ceramics are often hard. To make metals as hard as ceramics has been long-awaited in metals and ceramics communities. In this study, bulk nanocrystalline (NC) tungsten-1 wt% yttrium-0.7 wt% titanium (WYT) was fabricated via mechanical alloying followed by high-temperature/high-pressure sintering. The high pressure directly inhibits grain growth by suppressing atomic diffusion and indirectly inhibits grain growth by lowering sintering temperature, enabling the synthesis of dense NC WYT bulks with an average grain size of ∼ 9.0 nm. The high temperature causes annealing- and segregation-induced structural relaxation of grain boundaries (GBs) in sintered bulk NC WYT, resulting in GBs with a small excess volume of only ∼ 0.005 nm, one fifth that of bulk NC tungsten. The small grain size and the relaxed GBs in the bulk NC WYT make it hard for GBs to emit dislocations, resulting in extremely high hardness of 23.2 ± 0.3 GPa, yield strength of 9.4 ± 0.3 GPa, and ultimate compressive strength of 13.1 ± 1.1 GPa. The hardness of metallic bulk NC WYT is comparable to that of ceramic tungsten carbide (WC) whereas the wear rate of bulk NC WYT is even lower than that of WC. The structure-relaxed GBs lower the thermodynamic driving force for grain growth and result in an extremely high thermal stability - no grain growth occurs in bulk NC WYT annealed at a high temperature of 1500 °C, which is above the recrystallization temperature of tungsten. The present strategy - multifunctional treatments of NC alloy powders by high-temperature/high-pressure - provides a huge potential to manufacture dense bulk NC materials with exceptional mechanical property and thermal stability for practical applications.
研究领域:
材料科学
·
金属学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2018
·
IF 2.606
Kejia Kang,Rong Tu,Guoqiang Luo,Jian Zhang,Jiawen Zhu,Qiang Shen,Lianmeng Zhang
In this research, the high-temperature mechanical, electrical and thermal properties of arc-melted W-based composites with a small amount of SiC additives were investigated. The high-temperature mechanical properties of tungsten were enhanced by the presence of the hard ceramic phase (W 5 Si 3 and W 2 C) and the interaction of dislocations. The ceramic phase also played a role in inhibiting the grain growth at high temperatures. The ultimate compressive strength (UCS) of the W with 1 wt% SiC (S1) was 968.9 MPa at 1273 K, which is three times that of pure W (291.9 MPa) at 1273 K, showing a significant enhancement in high-temperature strength . Both thermal conductivity ( κ ) and electrical conductivity ( σ ) decreased with the increasing of SiC addition. With increasing temperature, the σ decreased while the κ increased due to the intrinsic behavior of the ceramic phase in the composites.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
SUPERLATTICES AND MICROSTRUCTURES
·
2019
·
IF 2.385
Guanguang Zhang,Xu Zhang,Honglong Ning,Huangxing Chen,Qiong Wu,Man Jiang,Conghao Li,Dong Guo,Yiping Wang,Rihui Yao,Junbiao Peng
Tungsten doped stannic oxide transparent conductive thin films (W-doped SnO 2 ) have been prepared via a solution process. We use stannous chloride, preoxotungstic acid (PTA), hydrogen peroxide and anhydrous ethanol to prepare precursor solution which is stable and colorless. By investigating the effects of tungsten doping ratio and annealing temperature on properties of tungsten doped stannic oxide films , it is found that the amounts of pores on surface can be reduced by increasing annealing temperature. Amorphous SnO 2 begins to transform into crystalline SnO 2 when annealed at 300 °C. The resistivity of 2 at.% W-doped SnO 2 achieves 2.94 × 10 −2 Ω cm annealed in air at 500 °C. The transmittance of W-doped SnO 2 films (around 87%) is better than that of pure SnO 2 films (around 83%) in visible range contrasted with blank quartz glass. The optical band gaps of both doped and pure SnO 2 films are over 3.7 eV.
研究领域:
材料科学
·
纳米技术
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2018
·Vol. 32
·期 5
·e4317
·
IF 3.581
Manman Jin,Guodi Zhang,Zhenmei Guo,Zhiguo Lv
Novel heterogeneous tungsten species in mesoporous silica SBA-16 catalysts based on ship-in-a-bottle methodology are originally reported for oxidizing cyclopentene (CPE) to glutaric acid (GAC) using hydrogen peroxide (H 2 O 2 ). For all W-SBA-16 catalysts, isolated tungsten species and octahedrally coordinated tungsten oxide species are observed while WO 3 crystallites are detected for the W-SBA-16 catalysts with Si/ W = 5, 10, and 20. The specific surface areas and the corresponding total pore volumes decrease significantly as increasing amounts of tungsten incorporated into the pores of SBA-16. Using tungsten-substituted mesoporous SBA-16 heterogeneous catalysts, high yield of GAC (55%) is achieved with low tungsten loading (for Si/W = 30, ~13 wt%) for oxidation of CPE. The W-SBA-16 catalysts with Si/W = 30 can be reused five times without dramatic deactivation. In fact, low catalytic activity provided by bulk WO 3 implies that the highly distributed tungsten species in SBA-16 and the steric confinement effect of SBA-16 are key elements for the outstanding catalytic performance.
研究领域:
化学
·
材料科学
·
催化
✓ 已验证
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2022
·
IF 3.118
Mingyan Chen,Dehua Zhang,Ziying Wang,Yao Zhang,Yucheng Liu
UiO-66 loading carboxyl and phosphotungstic acid has a good affinity to thiophene (TH). The synthesized catalyst, changed its original structure, which can increase its reactive site and enhance the interaction with thiophene (TH) in order to improve the adsorption performance. Then the structural changes were analyzed by XRD, FT-IR, SEM, BET, EDS and other characterization methods. Through static experiments of adsorption desulfurization, it is found that when the adsorption time is 240 min, the adsorption temperature is 30 ℃ and the oil-to-agent ratio is 100:1, the adsorption effect: UiO-66-(COOH) 2 (UC2) > UiO-66, the highest adsorption capacity can reach 89.99 mg/g; while PTA@UiO-66 (PAU) can reach adsorption equilibrium at 210 min, it has better desulfurization performance than UiO-66. After being recycled for 5 times, the adsorption effect is only slightly decreased: the adsorption capacity of UC2 was still 78.02% of the initial adsorption capacity, while that of PAU was 76.07% of the initial adsorption capacity. According to the adsorption kinetics, the adsorption process of thiophene on the adsorbent UC2 is more consistent with W-M model, and the adsorption of PAU is more in line with the pseudo-first order kinetic equation. In addition, it also includes the process of intraparticle diffusion and liquid film diffusion.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
He Xiao,Wenxiang Wang,Man Zhao,Zimei Fu,Meng Bai,Li Zhang,Junming Zhang,Ergui Luo,Jian Zhang,Haishun Wu,Jianfeng Jia
Cut-lost, highly active and stable (photo-)electrocatalysts are earnestly expected to overcome high energy obstacles in methanol oxidation reaction (MOR). A hybrid of NiW/graphene (NiW/G) is prepared by a simple self-designed electrosynthesis method. During the process of electrosynthesis, exfoliation of bulky graphite into graphene and generation of multivalent NiW bimetal precursor are both achieved. This obtained composite displays superior photoelectrocatalytic performance towards MOR. As for NiW/G-light, its area activity (peak current) and mass activity (peak current) are up to 343.4 mA cm −2 and 5960.7 mA mg −1 respectively, much higher than NiW/G, Ni/G and W/G. Operando electrochemical impedance spectroscopy, in-situ Fourier transform infrared spectroscopy and other ex-situ techniques uncover that the excellent MOR performance for NiW/G-light results from synergetic modulation of nickel sites by introducing tungsten and light, which provides desired adsorption behavior and high electrochemical active surface area. It’s found that introduction of W component promotes the formation of W-O-Ni(Ni 3+ ) species, supporting more strong adsorption sites for methanol. This results in new reaction path between adsorbed methanol and OH* for producing formic acid. With application of light, the photo-generated hole promotes oxidation of residual Ni 2+ into Ni 3+ species, which provides additional formed NiOOH sites for MOR. It’s concluded introduction of tungsten and light is efficient for greatly enhancing methanol electrooxidation. This work is highly instructive for application of self-designed electrosynthesis method to construct dimetal/graphene composite and photoelectric synergistic catalysis towards MOR.
研究领域:
材料科学
·
电化学
✓ 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）