CERAMICS INTERNATIONAL
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2024
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IF 5.1
Xincan Gao,Zhulin Huang,Jieyan Yuan,Xinyang Li,Ming Li,Xiaoye Hu,Yufei Tang,Yue Li
Tungsten carbide (WC) plays a crucial role as a source material in the production of cemented carbides . However, achieving precise control over the size and purity of WC powders remains challenging. In this study, we present an organic liquid phase precursor method for synthesizing ultrafine, high-purity tungsten carbide powders through carbothermal reactions. Specifically, hydroquinone serves as the carbon source and undergoes substitution reactions to bond with tungsten, leading to the formation of a molecularly dispersed W–O–C network structure. To diminish the free carbon content in WC particles, ammonium metatungstate (AMT), an auxiliary tungsten source, is homogeneously dispersed within the organic precursor solution. This allows the contained W and O elements to react with the excess carbon content, thereby reducing the free carbon content in the resulting WC powders. Following calcination at 1150 °C, the WC powders attains an average particle size of approximately 200 nm and experiences a reduction in free carbon content from 5.7 wt% to 1.1 wt%. In this way, the mechanical properties are greatly improved, with the hardness of WC block increased from 2.5 GPa to 19.3 GPa as carbon is eliminated. This study demonstrates the utilization of AMT as an effective regulating reagent for reducing the carbon content in cemented carbides, thus exhibiting potential for producing high-purity and ultrafine carbide powders.
研究领域:
材料科学
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无机化学
✓ 已验证
产品关联
DOI
高影响因子
SUPERLATTICES AND MICROSTRUCTURES
·
2019
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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
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纳米技术
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光电子学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Yanan Wang,Lipeng Zhang,Xiuxia Meng,Liu Feng,Ting Wang,Weimin Zhang,Naitao Yang
Developing highly efficient hydrogen evolution reaction (HER) electrocatalysts is of scientific and industrial importance. We report a hollow WC electrocatalyst obtained through a scalable strategy which is a combination of spray drying method with a subsequent gas-solid carburization reaction by using ammonium metatungstate (AMT) as the precursor. The as-prepared hollow structured WC catalyst has an improved BET surface area and a pore volume in comparison with the normal bulky WC (B-WC) catalyst synthesized using the same procedure but without the spray drying treatment for the precursor, which provides the hollow WC (H-WC) electrode a highly efficient catalytic structure to drive the electrocatalytic reactions such as HER. The attractive catalytic activity of this materials is that it can catalyze the HER over a wide pH range. And the comprehensive electrochemical characterization show the H-WC superstructure has the promising potential to be well coupled with many pH-dependent oxygen evolution reaction (OER) electrocatalysts in acid, neutral, and alkaline electrolytes for an overall water splitting reaction to generate hydrogen and oxygen.
研究领域:
材料科学
·
电化学
·
能源材料
·
催化
✓ 已验证
产品关联
DOI
高影响因子
Advanced Energy Materials
·
2024
·
IF 24.4
Qiaowei Lin,Jiaxing Liang,Ruopian Fang,Changlong Sun,Aditya Rawal,Jun Huang,Quan-Hong Yang,Wei Lv,Da-Wei Wang
Electrocatalysts can optimize the sulfur/sulfide reaction kinetics in Li–S batteries to compete with the loss of lithium polysulfides (LiPSs) caused by the shuttling effect. However, the design rationale of electrocatalysts to drive roundtrip sulfur/sulfide conversion is lacking. Here, pairing Lewis acidic and Lewis basic active sites to reach collective adsorption of LiPSs and simultaneous activation of electrophiles and nucleophiles in LiPSs is proposed. This concept is validated by doping polyaniline with protonated metatungstate anions, which enables reduced activation energies for both sulfur reduction reaction and sulfide oxidation reaction and results in significantly improved kinetics. Such electrocatalysts enable a Li–S battery to reach a low capacity-decay rate of 0.029% per cycle for 1000 cycles. This work would offer insights into battery technologies where sulfur electrocatalysis will play pivotal roles.
研究领域:
材料科学
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电化学
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电池技术
·
催化
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2024
·
IF 27.4
Fengluan Jiang,Yu Deng,Keyu Chen,Jichun Li,Xin-Yu Huang,Yidong Zou,Limin Wu,Wenhe Xie,Yonghui Deng
The straightforward synthesis of noble-metal-nanoparticle-decorated ordered mesoporous transition metal oxides remains a great challenge due to the difficulty of balancing the interactions between precursors and templates. Herein, a solvent-pair-enabled multicomponent coassembly (SPEMC) strategy is developed for straightforward synthesis of noble-metal-nanoparticle-decorated nitrogen-doped ordered mesoporous tungsten oxide (abbreviated as NM/N-mWO 3 , NM = Pt, Rh, Pd). The amphiphilic poly(ethylene oxide)- block -polystyrene (PEO- b -PS) copolymers coassemble with ammonium metatungstate (AMT) clusters and different kinds of hydrophilic noble metal precursors without phase separation. SPEMC synthesis requires no direct interaction between PEO- b -PS and AMT, thus the assembly equilibriums between noble metal precursors and PEO- b -PS can be readily controlled. The obtained NM/N-mWO 3 nanocomposites possess ordered mesopores, abundant oxygen vacancies, and metal–metal oxide interfaces. As a result, the Pt/N-mWO 3 sensors exhibit superior ammonia sensing performances with high sensitivity, an ultralow limit of detection (51.2 ppb), good selectivity, and long-term stability. Spectroscopic analysis reveals that ammonia is oxidized stepwise to NO, NO 2 − , and NO 3 − during the sensing process. Moreover, a portable wireless module based on Pt/N-mWO 3 sensor can recognize ppm-level concentration of ammonia, which lays a solid foundation for its application in various fields.
研究领域:
材料科学
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纳米技术
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化学传感器
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）