Materials Today Communications
·
2024
·
IF 3.7
Yuhui Chen,Zhenhua Hao,Rulong Ma,Pei Wang,Yongchun Shu,Jilin He
In this study, a new unmixed carbon reduction method was proposed for the preparation of pure W powder. The effects of reduction temperature, reduction time, carbon distance and thickness of WO 3 layer on the phase of the reduction products were investigated. Results show that pure tungsten powder with a carbon content of less than 150 ppm can be prepared at 950 °C with a WO 3 layer thickness of 5 mm and a carbon distance of 2 mm. Increased carbon distance and thickness of WO 3 layer will lead to a decrease in the reduction ratio. Additionally, particle size of the tungsten powder gradually increases from 1 μm to 8 μm due to sintering with the extended reduction time. Furthermore, a two-stage carbon reduction process with WO 2 as an intermediate product is proposed, which avoids the sintering and growth of tungsten powder particles and the particle size of tungsten powder was successfully reduced to 2 μm. This unmixed carbon reduction reduces the carbon concentration and prevents the carbonization of tungsten powder. The experiment verifies the feasibility of carbon as a reducing agent in producing pure tungsten powder by reducing WO 3 .
研究领域:
材料科学
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冶金学
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产品关联
DOI
高影响因子
Nanomaterials
·
2020
·Vol. 10
·期 11
·2206
·
IF 4.324
Gaoqian Yuan,Gen Zhang,Kezhuo Li,Faliang Li,Yunbo Cao,Jiangfeng He,Zhong Huang,Quanli Jia,Shaowei Zhang,Haijun Zhang
Loading a noble metal on Bi4Ti3O12could enable the formation of the Schottky barrier at the interface between the former and the latter, which causes electrons to be trapped and inhibits the recombination of photoelectrons and photoholes. In this paper, AgPt/Bi4Ti3O12composite photocatalysts were prepared using the photoreduction method, and the effects of the type and content of noble metal on the photocatalytic performance of the catalysts were investigated. The photocatalytic degradation of rhodamine B (RhB) showed that the loading of AgPt bimetallic nanoparticles significantly improved the catalytic performance of Bi4Ti3O12. When 0.10 wt% noble metal was loaded, the degradation rate for RhB of Ag0.7Pt0.3/Bi4Ti3O12was 0.027 min−1, which was respectively about 2, 1.7 and 3.7 times as that of Ag/Bi4Ti3O12, Pt/Bi3Ti4O12and Bi4Ti3O12.The reasons may be attributed as follows: (i) the utilization of visible light was enhanced due to the surface plasmon resonance effect of Ag and Pt in the visible region; (ii) Ag nanoparticles mainly acted as electron acceptors to restrain the recombination of photogenerated electron-hole pairs under visible light irradiation; and (iii) Pt nanoparticles acted as electron cocatalysts to further suppress the recombination of photogenerated electron-hole pairs. The photocatalytic performance of Ag0.7Pt0.3/Bi4Ti3O12was superior to that of Ag/Bi4Ti3O12and Pt/Bi3Ti4O12owing to the synergistic effect between Ag and Pt nanoparticles.Keywords:photocatalytic;Rhodamine B;photoreduction;Bi4Ti3O12;AgPt/Bi4Ti3O12
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
PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2016
·
IF 1.207
Lei Yang,Yangyang Zhang,Hua Li,Hezhou Liu
Metallic bismuth crystal is one important and interesting semimetal that has attracted great attention owing to its unique thermal and electrical properties. Herein, we report a facile, green, cost-effective and sustainable solvothermal process using ethanol, glycol, isopropanol, phenylcarbinol as solvent and commercial Bi 2 O 3 as the starting material to produce high-purity metallic Bi with tunable morphologies on large scale. It is found that all alcohols are capable of reducing Bi 2 O 3 to Bi and the reducibility of glycol is proved to be the strongest. The highest purity of the resultant Bi is calculated to be 99.74%. What's more, the morphology of final Bi particles is controllable by adding various types and concentrations of additives. As a consequence, our work lays the root for the large scale solvothermal production of high-purity Bi particles with various regular morphologies.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2023
·Vol. 76
·期 2
·969-975
·
IF 2.6
Liu Hanning,Liu Peidong,Tian Qinghua,Dong Zhaowang,Chen Yubing,Guo Xueyi
Fe-36Ni invar alloys (Invar 36 alloys), which have a low thermal expansion coefficient (CTE) and good mechanical properties, are typically produced through a high-pollution smelting process. A green and quick-process method for the two-step hydrogen reduction of a designed mixture of Fe 2 O 3 and NiO powders was developed to prepare Fe-36 wt.%Ni alloys. A dense Fe-36 wt.%Ni alloy with an oxygen content of 0.20 wt.% was successfully produced. A single γ -FeNi phase was identified at 1000°C, whereas grains and twins became more evident at 1100°C. The final alloy exhibited excellent mechanical properties at room temperature, showing a hardness of 154 HV, a tensile strength of 486 MPa, a yield strength of 251 MPa, and a fracture strain of 21%.
研究领域:
材料科学
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冶金工程
·
结构合金
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2023
·
IF 3.8
Yuhui Chen,Ruihua Zhang,Zhenhua Hao,Yongchun Shu,Jilin He
In this study, MoO 2 was reduced by an unmixed carbon reduction method. Effects of reduction temperature, reduction time and distance between carbon and MoO 2 on the phase composition of reduction products were investigated. Results show that the phase change during the reduction process are MoO 2 →Mo 2 C→Mo with the increase of temperature. The reduced product is Mo 2 C when reduction temperature is 1000 °C and 1050 °C. Pure Mo can be obtained when the reduction temperature increases to 1100 °C. The reduced product changed from nearly spherical Mo particles with fine molybdenum dioxide particles attached on surface to polyhedron Mo particles with smooth surface when the distance between carbon and MoO 2 decreases from 10 mm to 1 mm. The reaction showed a similar change with the changes of the reaction time. The difference is that there will be residual Mo 2 C in reduced product when reduction time was 1 h. This method of carbon reduction can provide low carbon concentration by controlling the carbon distance to avoid the existence of molybdenum carbide in the product of molybdenum preparation.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Yu Wang,Xiao-Hui Yang,Jian Cui,Guo-Hua Zhang
Rare-earth hexaborides (REB 6 ) are vital raw materials for cathode materials and high temperature structural ceramics that are widely applied as high-frequency electron tubes and ceramics adaptive for extreme environment, respectively. In this work, single phase substitutional solid solution REB 6 (LaB 6 , La 0.75 Ce 0.25 B 6 , La 0.5 Ce 0.5 B 6 , La 0.25 Ce 0.75 B 6 and CeB 6 ) powders were prepared with the raw materials of La 2 O 3 , CeO 2 , B 4 C and Al powders, after calcining at 1773 K for 4 h and the following alkaline leaching. All substitutional solid solution products have homogeneous distributions of La and Ce in particles. Through microscopic morphology analysis, it is discovered that the formation of solid solution is beneficial for reducing the particle size of product, relative to LaB 6 and CeB 6 . Moreover, Al flux plays an important role in decarbonizing reaction, and C contents of all products are below 0.4 wt%.
研究领域:
材料科学
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无机化学
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产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2023
·
IF 5.7
Tao Zhang,Guiqing Zhang,Zuoying Cao,Mingyu Wang,Wenjuan Guan,Shengxi Wu,Qinggang Li
Background The NH 3 , a clean reductant, generated by the thermolysis of NH 4 VO 3 , is not effectively utilized in the conventional process of vanadium metallurgy. Additionally, the preparation process of V 2 O 3 is both long and costly. Ammonia recovery is essential to prevent environmental issues resulting from ammonia release. By direct thermolysis of NH 4 VO 3 and effectively utilizing of active NH 3 , it is possible to achieve the short flow and green process for the production of V 2 O 3 . Method In an open NH 3 atmosphere, one end of the flange was connected to the liquid ammonia gas cylinder, while the other end was connected to the tail gas absorber. Furthermore, in a closed NH 3 atmosphere, both ends of the tube furnace were sealed with flanges, and the initial atmosphere in the tube was pre-injection NH 3 . The products of NH 4 VO 3 thermolysis were characterized using various techniques, including XRD, FT-IR, ICP-OES, SEM, XPS, and TG. Significant finding The thermolysis process of NH 4 VO 3 with pre-injection of NH 3 under the sealed condition was a simulation of the continuous production process of V 2 O 3 using a rotary kiln in industrial production. The rational utilization of ammonia resulted in the reduce of energy consumption, extra reductant consumption, and significant NH 3 emissions compared to the traditional V 2 O 3 production process. It was observed that V 2 O 3 was easily obtained through the thermolysis of NH 4 VO 3 with pre-injection of NH 3 under the sealed condition at 600 °C for 3 h, using a dosage of NH 4 VO 3 ranging from 2 g to 10 g. During this process, the NH 4 VO 3 went through the phase transition as follows: NH 4 VO 3 →NH 4 V 3 O 8 →(NH 4 ) 0.38 V 2 O 5 →V 6 O 13 →VO 2 →V 4 O 7 →V 3 O 5 →V 2 O 3 , and the relevant characterization of products showed that the V 2 O 3 obtained was qualified. These experimental results were of great significance to the industrial practice of vanadium metallurgy. Based on these results, short flow and green process of V 2 O 3 could be achieved in industry by partially improving the calcination process of NH 4 VO 3 in large-scale rotary kilns.
研究领域:
冶金学
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材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2020
·
IF 7.888
Shuo Geng,Weiwei Yang,Yequn Liu,Yongsheng Yu
Engineering sulfur vacancies in the basal plane of MoS 2 is an effective method to enhance its catalytic activity. However, the traditional methods are only effective for multilayer or monolayer MoS 2 supported on the substrate (such as Si/SiO wafer or carbon paper), which are not applied in bulk or commercial MoS 2 . In this work, we developed a simple and general chemical reduction method for engineering S-vacancies in the MoS 2 basal plane and additional active edge sites, which can be exploited to improve the HER catalytic performance of MoS 2 . The optimized MoS 2 nanosheets with S-vacancies exhibit excellent HER activity with a small overpotential of 190 mV at large density of 10 mA/cm 2 and a low Tafel slope of 54 mV decade −1 . Moreover, prominent electrochemical durability was also achieved. This finding proposes an effective strategy to fabricating S-vacancies for activating basal plane of 2D transition metal chalcogenides materials.
研究领域:
材料科学
·
电化学
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产品关联
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2020
·Vol. 27
·期 1
·37-45
·
IF 1.713
Wang Yu,Zhang Guo-hua,Wu Yue-dong,He Xin-bo
The method of calciothermic reduction of B 4 C was proposed for preparing CaB 6 . The phase transition and morphology evolution during the reaction were investigated in detail. The experimental results reveal that Ca first reacts with B 4 C to generate CaB 2 C 2 and CaB 6 at a low temperature and that the CaB 2 C 2 subsequently reacts with Ca to produce CaB 6 and CaC 2 at a high temperature. After the products were leached to remove the byproduct CaC 2 , pure CaB 6 was obtained. The grain size of the prepared CaB 6 was 2–3 μm, whereas its particle size was 4–13 μm; it inherited the particle size of B4C. The residual C content of the product was decreased to 1.03wt% after the first reaction at 1173 K for 4 h and the second reaction at 1623 K for 4 h.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2018
·
IF 2.32
Ning Wang,Dongyan Tang,Hongyun Zou,Shuyue Jia,Zhaojie Sun,Xu Yang,Jing Peng
A reduction method was proposed to synthesize better dispersed molybdenum oxide quantum dots (MoO x QDs) with stable fluorescence properties by using molybdenum disulfide (MoS 2 ) and hydrogen peroxide (H 2 O 2 ) as precursor and oxidant, and using ethanol as reducing agent and surfactant of oleylamine as modified agent. The morphology of the as-prepared MoO x QDs with average size of 1.96 nm were observed, calculated and analyzed from TEM and AFM detections. Excitation-dependent photoluminescence emission of MoO x QDs could be obtained and MoO x QDs exhibited blue fluorescence under UV light irradiation. Factors that influenced the syntheses of MoO x QDs were discussed, and the highest value of fluorescence intensity was exhibited with the adding of 5 mL oleylamine and the reaction time of 24 h. The cell imaging behaviors, the physiological stabilities and in vitro cytotoxicity testing of MoO x QDs were further discussed with HeLa cells as model. And the results showed that it might be a promising biomedical material as high quality fluorescent probes for bio-imaging.
研究领域:
材料科学
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生物医学工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2018
·
IF 3.306
Qing Li,Xiaofang Zhu,Ying Zhang,Zhigang Zak Fang,Shili Zheng,Pei Sun,Yang Xia,Ping Li,Yang Zhang,Xing Zou
Hydrogen assisted magnesiothermic reduction (HAMR) of TiO 2 is a promising new process developed recently to produce Ti metal with low cost and less energy consumption. This work focuses on the understanding and optimization of the reduction process to control the quality of the reduced product. TiO 2 precursor particles with different relative densities were prepared, and the effects of the relative densities on reduction by Mg in H 2 were studied. The changes of oxygen contents vs. reduction time at various temperatures were investigated. The phase transformations during the reduction were analyzed both theoretically and experimentally. The relationship between the morphology of the reduced products and the relative densities of the TiO 2 precursors was analyzed by SEM characterization and the likely reason for the morphology evolution was discussed.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
SOLID STATE SCIENCES
·
2023
·
IF 3.5
Guang Yang,Hengwei Yan,Zhanwei Liu,Wenhui Ma,Shenghui Guo,Yonghui Yang
In this study, aluminothermic reduction and molten salt electrolysis were combined to prepare titanium powder. In this combined method, titanium dioxide was first deoxidized to produce titanium–aluminum alloy through an aluminothermic reduction reaction, and then the titanium–aluminum alloy was separated through chloride molten salt electrolysis to generate titanium powder. The obtained titanium powder, titanium aluminum alloy and slag was analyzed using several techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. A mass ratio of 2:3 of titanium dioxide and aluminum was suitable for the production of titanium–aluminum alloys. A large amount of alumina generated through the aluminothermic reduction reaction was separated into slag phases using cryolite. Then, the phases were electrolyzed into aluminum and cryolite, which were reused as raw materials. The final titanium–aluminum alloy product was electrolyzed in a chloride molten salt system to separate titanium and aluminum and produce titanium powder. Therefore, the combination of thermal reduction and molten salt electrolysis is efficient and has great potential for producing high-purity titanium powder.
研究领域:
材料科学
·
冶金工程
✓ 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）