CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Mengchuan Li,Tongsheng Zhang,Rensheng Li
The thermodynamic data of rare earth-containing systems are crucial for the development and application of permanent magnets, optoelectronic materials, high-temperature superconducting materials, and catalysts. In this study, the equilibrium phase compositions of the CaO-Ce 2 O 3 -SiO 2 -(5∼25 wt%) Al 2 O 3 system at 1873 K were investigated through high-temperature equilibrium experiments. The equilibrium phase compositions at 1873 K were determined using SEM, XRD, and EPMA, leading to the construction of isothermal sections. For the CaO-Ce 2 O 3 -SiO 2 -5 wt% Al 2 O 3 system, the isothermal cross-section diagram revealed a liquid phase region, four distinct two-phase equilibria, and two different three-phase equilibria. As the Al 2 O 3 content increased to 25 wt%, the isothermal cross-section diagram showed a liquid phase region, five different two-phase equilibria, and three distinct three-phase equilibria. The experimental results provide valuable insights for further research on the practical applications of cerium-containing rare earths in various fields.
研究领域:
材料科学
·
热力学
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产品关联
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 7
·3653-3660
·
IF 3.049
Guang Xiong,Miaomiao Feng,Jiaxu Liu,Qingrun Meng,Liping Liu,Hongchen Guo
An aerosol-assisted hydrothermal method has been applied to synthesizing hierarchical beta zeolites with SiO2/Al2O3 ratios ranging from 44 to 392 in NaF media. Two different morphologies, including nano-aggregates with interparticle mesopores and plate-like zeolites with intracrystalline mesopores, can be formed depending on the SiO2/Al2O3 ratios of the synthesis gels. A possible mechanism for the formation of the beta zeolites has been proposed. The obtained beta zeolites show hierarchical pores, good Al species distribution and less internal defect sites. Evaluation, by the cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB), is consistent with the acidic properties and the pore structure of beta zeolites with different ratios of SiO2/Al2O3.
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
CHINESE JOURNAL OF CATALYSIS
·
2018
·
IF 3.525
Dawei He,Danhua Yuan,Zhijia Song,Yunpeng Xu,Zhongmin Liu
Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure-directing agents (OSDAs), which are chronically hazardous to humans and the environment. It is a growing trend to develop an eco-friendly and nuisanceless OSDA for zeolite synthesis. Herein, choline is employed as a non-toxic and green OSDA to synthesize high silica Y zeolite with SiO 2 /Al 2 O 3 ratios of 6.5–6.8. The prepared Y zeolite samples exhibited outstanding (hydro)thermal stability at ultrahigh temperature owing to the higher SiO 2 /Al 2 O 3 ratio. The XRF, SEM, 29 Si-NMR and 13 Na+ results suggested that choline plays a structure-directing role in the synthesis of Y zeolite, while the feed molar fraction of Na + is a crucial determinant for the framework SiO 2 /Al 2 O 3 ratio and the crystal morphology.
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
FUEL
·
2024
·
IF 6.7
Jingyi Ma,Hui Yuan,Changcheng Liu,Jieguang Wang,Rongxin Zhang,Aizeng Ma
Propane dehydrogenation (PDH) is used to increase propylene production and to produce hydrogen as a by-product. Despite the widespread utilisation of Pt-loaded catalysts in industrial PDH operations, challenges such as excessive noble metal loading and coking persist in the face of rigorous reaction conditions. These hindrances limit to achieving the optimal economic efficiency. In this work, we report a method aimed at reducing Pt loading to only 0.05 wt% through synergistic modification of GaPt catalysts loaded on SiO 2 -Al 2 O 3 supports (i.e. SIRAL) with K and Ce. The resulting catalysts exhibit remarkable stability and elevated activity for propane dehydrogenation. The K + and SiO 2 could modulate the support surface acidity and immobilizes the active tetrahedral Ga 3+ sites, which improves the catalytic performance and reduce coke deposition. Furthermore, the inclusion of Ce decreases the electron density of the Pt species, stabilizing the atomically dispersed Pt and enhances the formation of active Pt sites, which effectively impedes the Pt agglomeration. As a result, the GaPtKCe/SIRAL10 catalyst demonstrates excellent catalytic performance, achieving 47% propane conversion and >96% propylene selectivity, while maintaining notable stability with 0.016 h −1 deactivation rate constant at 580 °C, even without hydrogen co-feed.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2024
·
IF 6.2
Ruijing Sun,Jinhu Wu,Hui Wang,Wei Zhang,Chao Liu,Shaopeng Gu,Weihong Xing,Liang Yu
The reaction behavior between the carbon and mold fluxes during the heating process is vital for a successful continuous casting process and the high billet quality. A detailed investigation combined with thermogravimetry-mass spectrometry (TG-MS), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and transmission electron microscopy (TEM) techniques was carried out to systematically investigate the transformation mechanistic of the macro physicochemical properties, melting behavior, viscosity, crystallization, and heat transfer performance caused by the reaction behavior. The results showed that the mold flux underwent carbonate decomposition (973–1223 K), solid reaction (1273–1573 K), and melting process (1473–1673 K) during the continuous casting process. The carbon-bearing mold flux exhibited an endothermic peak at approximately 1673 K, corresponding to a weight loss ratio of approximately 14.5% on the TG curve, confirming that carbon could react with the middle mineral phases Ca 2 SiO 4 , Ca 2 Al 2 SiO 7, and Na 6 Ca 3 Si 6 O 18 to form SiC, increasing the breaking temperature by approximately 293 K. SEM and TEM results indicated that the melting behavior was restrained by the carbon itself and the newly formed components. Besides, the addition of carbon increased the degree of polymerization of molten slag, the thickness of slag film and the proportion of small crystals in slag film, further leading to an increase in crystallization and heat transfer performances. The reaction mechanism between carbon and slag and the subsequent effects on melting point, viscosity, crystallization ratio and heat flux density were clearly understood, which is meaningful for the carbon blending process of the mold flux.
研究领域:
材料科学
·
冶金工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Dewei Ma,Panli Zhu,Jun Huang,Xiuhua Cao
The research on low-temperature lead-free glass is of great significance for the miniaturization, integration and intelligence of current electronic products, as well as environmental protection. In this article, we report the preparation of low-temperature lead-free B 2 O 3 -BaO-ZnO-SiO 2 -Al 2 O 3 -TeO 2 glasses by a melt-quenching technique. With the increase of TeO 2 content in glass, the glass transition temperature and melting temperature of sintered glass powder decrease, while its wettability and acid corrosion resistance show an increasing trend. The application of glass powder in the sintering experiment of terminal electrode slurry further proves this viewpoint. Compared with the poor sintering performance of the slurry with TeO 2 -free glass powder, the slurry containing TeO 2 glass powder forms a very dense sintered solid, and the sintered slurry is tightly bonded to the ceramic substrate .
研究领域:
材料科学
·
环境科学
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产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2020
·Vol. 52
·期 1
·314-321
·
IF 2.035
Ren Guoxing,Xiao Songwen,Xia Longgong,Liao Caibin,Liu Zhihong
To obtain fundamental information on the dissolution of cobalt into alumina-saturated MnO-SiO 2 -Al 2 O 3 slags in the smelting reduction of spent lithium-ion batteries, the equilibrium distribution of cobalt between Co-Cu alloys and alumina-saturated MnO-SiO 2 -Al 2 O 3 slags was measured at 1573 K and 1623 K under a controlled CO-CO 2 atmosphere. The results show that (i) the solubility of cobalt in the slag increased with increasing concentration of cobalt in the alloy and increasing oxygen partial pressure in the atmosphere at a fixed concentration of cobalt in the alloy, and (ii) the activity coefficient of CoO in the slag increased with increasing cobalt oxide in the slag. The activity coefficient of CoO in the slag, γ CoO, referred to as solid CoO, can be described as a function of the concentration of CoO in slag as follows: γ CoO = 11.2957(wt pct CoO in slag) + 12.0944 (1573 K, (wt pct MnO)/(wt pct SiO 2 )= 0.76–0.83); γ CoO = 2.2286(wt pct CoO in slag) + 4.5232 (1623 K, (wt pct MnO)/(wt pct SiO 2 )= 0.78–0.85).
研究领域:
冶金学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Yansong Liu,Wenbo Li,Yongsheng Liu,Yu Pan,Yejie Cao,Xiang Zheng,Jian Chen,Yijiang Zeng
In this work, alumina was selected as the second phase reinforced fused quartz ceramics and SiO 2 –Al 2 O 3 composite ceramics were fabricated via digital light processing (DLP) 3D-printing. The effect of the sintering procedure on the mechanical and dielectric properties of SiO 2 –Al 2 O 3 composite ceramics were investigated in detail. The results show that the amount of cristobalite precipitation is the key factor affecting the properties of composite ceramics. The amount of cristobalite precipitation in composite ceramics could be controlled effectively by adjusting the heating rate, holding time, and sintering temperature. The sintering procedure is set as the heating rate of 4°C/min, sintering temperature of 1200°C, and holding time for 2 h, the flexural strength of SiO 2 –Al 2 O 3 composite ceramic is 47.13 MPa, dielectric constant ranges from 2.90 to 2.97, and the tangent of loss angle is less than 0.041. SiO 2 –Al 2 O 3 composite ceramics with high flexural strength and low dielectric constant were obtained by sintering procedure screening and optimization.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2024
·
IF 4.7
Yue Li,Huan Ren,Daolai Sun,Xinqiang Zhao
Vapor-phase catalytic deoxydehydration of 1,2-propanediol (1,2-PDO) to form propylene was performed over various metal-loaded catalysts in an H 2 flow at an ambient pressure. Cu-based catalysts exhibited a relatively high activity for the formation of propylene, while other metal-based catalysts, such as Pt-, Ru-, Rh-, Ni-, and Co-loaded SiO 2 -Al 2 O 3 , primarily produced C-C bond cleavage products. Cu-loaded H 3 PO 4 /SiO 2 -Al 2 O 3 catalysts showed the best catalytic performance, and the catalyst with a Cu and H 3 PO 4 loading of 8 and 10 wt%, respectively, could provide a propylene selectivity of 95.0% with a complete conversion of 1,2-PDO at 280 °C. The Cu-loaded H 3 PO 4 /SiO 2 -Al 2 O 3 catalysts primarily contained Lewis acid sites, and the Cu particles were well dispersed on the catalyst surface with an averaged particle size of 3.1 nm. It is proposed that the vapor-phase deoxydehydration of 1,2-PDO to propylene undergoes multi-step reactions with propanal and 1-propanol as the reaction intermediates.
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 RARE EARTHS
·
2023
·
IF 4.9
Falin Zhang,Xiaoying Liang,Rongfei Wei,Hai Guo,Fangfang Hu
In this work, a group of Bi 3+ /Eu 3+ -doped SiO 2 –Al 2 O 3 -MCO 3 (M = Ca, Sr, Ba) glasses were fabricated through melt-quenching method. Their structure and photoluminescence characters were studied via X-ray diffraction (XRD), UV–Vis transmission spectra (TRS), excitation spectra, emission spectra and decay lifetimes. The XRD results show that no nano-crystal phase forms in glass matrix with different doping concentrations of Bi 3+ and Eu 3+ ions. Through regulating optical alkalinity value, the intensity of Bi 3+ ions increases and the peak position shifts to red wavelength. The Bi 3+ /Eu 3+ co-doped glasses show a blue-white-yellow-red luminescence by changing concentration of Eu 3+ ions. Energy transfer efficiency from Bi 3+ to Eu 3+ can reach as high as 10.54%. At 423 K, the emission intensity of 55SiO 2 –10Al 2 O 3 –35BaO-0.25Bi 2 O 3 (GBE0.5) is 31.1% of that at 308 K. Meanwhile, the activation energy of the glass matrix is 0.251 eV. All results suggest that these Bi 3+ /Eu 3+ co-doped glass samples possess potential application in LED field.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
ChemCatChem
·
2023
·
IF 4.5
Weijun Shan,Ruixi Yang,Yushan Jia,Xianghan Liu,Xinwei Du,Haibiao Yu,Ying Xiong
Graphical The porous amorphous ASA(Si/Al=20) was quickly synthesized by gel-gel method in one step, and used to catalyze γ-valerolactone (GVL) to butane. It has large specific surface area (430.20 m 2 g −l ), suitable Brønsted/Lewis ratio (0.66) and enough weak acid site content (0.5554 mmol g −1 ). Under the optimized reaction conditions, 90 % butene yield can be obtained in 180 min at 300 °C. In this study, porous amorphous SiO 2 −Al 2 O 3 (ASA(Si/Al= x )) with different Si/Al ratios was synthesized by gel-gel method, and used to catalyze green renewable energy source γ-valerolactone (GVL) to butene. Research indicated that all prepared catalysts had large amounts of disordered mesoporous with the pore size in range of 2–13 nm. For the optimal ASA(Si/Al=20) catalyst, its specific surface area is 430.20 m 2 g −l and pore size is about 8.13 nm. Due to the presence of suitable Al species, ASA(Si/Al=20) has the largest Brønsted/Lewis ratio and 0.5554 mmol g −1 weak acid site content. Under the optimized reaction conditions, 90 % butene yield can be obtained in 180 min at 300 °C. In addition, the regeneration performance of the ASA(Si/Al=20) catalyst is also satisfactory, and the yield of butene can be above 60 % after 5 th cycles. After activation, the spent catalyst can be regenerated, and about 78 % butene yield can be also obtained.
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产品关联
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2022
·Vol. 128
·期 12
·1-18
·
IF 2.983
He Yuan,Guo Shenghui,Li Shiwei,Yin Shaohua
Y Zeolite plays an irreplaceable role in many important applications due to its unique physicochemical properties, which has attracted extensive attention from researchers. Response surface methodology (RSM) was used to optimize the process parameters for the hydrothermal synthesis of Y zeolite using kaolin activated by microwave heating. The best relative crystallinity was 108.17% could be achieved at the condition: the aging temperature of guiding agent was 65 ℃, the crystallization temperature was 100 ℃, the crystallization time was 24 h. In addition, the aging temperature of guiding agent was the most important influence factor. Under the optimal condition, the SiO 2 /Al 2 O 3 ratio of synthesized Y zeolite was 4.54, 90% of the particle size was less than 60 μm, and the specific surface area of Y zeolite was 479 m 2 /g. The successful preparation of Y zeolite with high crystallinity is expected to provide reference for the application of wastewater treatment, CO 2 sequestration and fluid catalytic cracking for petroleum.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 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）