APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Pengjing Chen,Guofeng Zhao,Ye Liu,Yong Lu
A series of Ni 5 Ga 3 / m -SiO 2 /Al 2 O 3 /Al-fiber ( m = 0, 0.5, 1.0, 3.0 and 5.0 wt%) catalysts have been developed for CO 2 hydrogenation to methanol at ambient pressure. Microfibrous-structured SiO 2 /Al 2 O 3 /Al-fiber supports are obtained though endogenous growth of free-standing boehmite (AlOOH) nanosheets onto a three-dimensional (3D) network of 60 μm-Al-fiber thin felt with the aid of steam-only hydrothermal oxidation reaction between Al metal and H 2 O (2 Al + 4H 2 O → 2 AlOOH + 3H 2 ), followed by calcination and SiO 2 -modification using silica sol. The bimetallic Ni 5 Ga 3 nanoparticles are then placed onto the pore surface of as-obtained SiO 2 /Al 2 O 3 /Al-fiber support by co-impregnation method using Ni and Ga nitrates as precursors followed by reduction in H 2 at 630 °C. The promising Ni 5 Ga 3 /1-SiO 2 /Al 2 O 3 /Al-fiber catalyst is capable of converting 2.3% CO 2 into CH 3 OH with a high selectivity of 86.7% as well as 10.3%/3.0% selectivities to CO/CH 4 at 210 °C, for a feed of CO 2 /H 2 /N 2 (2/6/1, molar ratio). Such microfibrous-structured catalyst design combines the promising catalytic performance of Ni 5 Ga 3 with the enhanced heat transfer and high permeability of the Al 2 O 3 /Al-fiber support. The effect of SiO 2 loading on the formation of Ni 5 Ga 3 alloy nanoparticles is also discussed.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
STEEL RESEARCH INTERNATIONAL
·
2024
·
IF 1.9
Li Zhang,Hang He,Lei Zhang,Yongqi Sun,Xu Gao,Jie Zeng,Wanlin Wang
Viscosity is an important property for CaO-SiO 2 -Al 2 O 3 -based slag systems, which showcases different scenarios in basic and acid slag systems with temperature change. This article elucidates the mechanism of their difference in viscosity–temperature property from melt structure. Results reveal that basic slag shows a low degree of polymerization (DOP) and a low viscosity of the melt due to an excessive O 2− ions depolymerizing the complex network structures, resulting in more low-polymerized Q 0 (Si) units and less high-polymerized Q 3 (Si) units. With the temperature decreases, the DOP and viscosity do not change significantly. However, the low DOP and viscosity favor crystal precipitation in the melt, leading to a solid–liquid mixed state of the slag, and thus a sharp increase in viscosity when the temperature decreases to 1275 °C. For acid slag, it undergoes a transformation into aluminosilicate structures with the introduction of numerous [AlO 4 ] 5− tetrahedra, accompanied by a significant increase in the relative mole fraction of high-polymerized Q 3 (Si) units. Consequently, the DOP and viscosity are obviously higher than that of the basic slag. Furthermore, the DOP and viscosity of the acid slag increase continuously with the temperature decreasing, thus impeding crystal precipitation and enhancing the glass transition tendency of the molten slag.
研究领域:
材料科学
·
冶金学
✓ 已验证
DOI
高影响因子
Coatings
·
2022
·Vol. 12
·期 10
·1503
·
IF 3.236
Wenbo Li,Min Feng,Lanlan Liu,Jun Zhang,Bo Hu,Qiao Cheng
Compressor blades made of TC4 that are serviced in marine environments suffer from severe active corrosion under the synergetic effect of NaCl and H2O(g). A SiO2-Al2O3glass composite coating was applied on TC4 substrate for protection by first air spraying slurry and subsequent a suitable sintering process. The corrosion behavior of the SiO2-Al2O3glass composite coating and uncoated alloy in marine environment under the simultaneous effect of NaCl(s) and H2O(g) at 650 °C were investigated. The results indicated that the SiO2-Al2O3glass composite coating presented good corrosion behavior and provided protection for the alloy; the superior corrosion resistance is mainly attributed to the favorable effect of the SiO2-Al2O3glass composite coating on inhibiting self-sustainable oxychlorination. The detrimental effect of Ti on self-sustainable oxychlorination mechanism in marine environment are discussed.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Yue Li,Huan Ren,Daolai Sun,Xinqiang Zhao,Satoshi Sato
Liquid-phase catalytic hydrodeoxygenation of 1,2-decanediol (1,2-DDO) to form 1-decanol was performed over various non-noble metal-loaded acidic catalysts, and Cu loaded on amorphous SiO 2 -Al 2 O 3 exhibited a high catalytic activity for the formation of 1-decanol. A high 1-decanol selectivity of 84.7% with a complete 1,2-DDO conversion was obtained within only 15 min over the Cu/SiO 2 -Al 2 O 3 at 250 °C under 10 MPa H 2 pressure. The temperature at 250 °C and the H 2 pressure higher than 3 MPa were conducive to the efficient production of 1-decanol from 1,2-DDO. In contrast to the previously reported noble metal catalysts, Cu/SiO 2 -Al 2 O 3 required a relatively high reaction temperature, while an extremely high 1-decanol productivity of 78 mmol g cat −1 h −1 could be achieved. Meanwhile, the hydrodeoxygenation of 1,2-decanediol over Cu/SiO 2 -Al 2 O 3 proceeded via a reaction mechanism in which decanal was formed as the intermediate. In addition, the Cu/SiO 2 -Al 2 O 3 catalyst was reusable at least five times without serious deactivation.
研究领域:
催化化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2024
·
IF 3.4
Yang Zhang,Qizhuang Zou,Ruiqi Fang,Hua Tan,Hongbing Ji,Yingwei Li
Yolk-shell nanoreactors feature numbers of advantages in promoting catalytic performance. This work demonstrates the fabrication of yolk-shell Fe 3 O 4 @SiO 2 /Al 2 O 3 - T ( T = 500–900 °C) from metal-organic framework. Characterizations indicate the Fe 3 O 4 yolk and SiO 2 /Al 2 O 3 shell of the obtained nanoreactors. Fe 3 O 4 @SiO 2 /Al 2 O 3 –800 showed excellent performance in furfural acetalization to 2-(dimethoxymethyl)furan, achieving a 97% yield at 60 °C, atmospheric pressure within 5 h. Control experiments reveal the high reactivity of Fe 3 O 4 yolks for furfural acetalization, and acidic Al species are favorable for reactivity promotion. Besides, porous SiO 2 /Al 2 O 3 shells facilitate mass transfer and increase the accessibility of active sites, also contribute to the high performance and stability.
研究领域:
化学工程
·
纳米材料科学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2017
·
IF 2.124
Ren Gao,Huanping Wang,Qingong Zhu,Qinghua Yang,Xingguo Sun,Bingpeng Li,Shiqing Xu,Xianghua Zhang
The glasses of 93.9% ( x SiO 2 - y Al 2 O 3 - z MgO)-5% CaO-1% B 2 O 3 -0.1% Fe 2 O 3 were prepared, and the relationship between mechanical properties and structural stability were characterized by means of Raman spectroscopy and optical band gap values. The glass forming region is found to be x = 50–70%, y = 10–25% and z = 15–32%. As x = 65%, y = 10% and z = 25% (SAM-4), the investigated glass possesses the optimum volume density, oxygen packing density, optical band gap, banding strength , compression strength and compression modulus, which are 2.517 g/cm 3 , 77.047 mol/l, 3.56 eV, 77.04 MPa, 202.74 MPa and 106.70 GPa, respectively. Meanwhile, starting from the representative point of SAM-4 to radiate around, the volume density, oxygen density, Raman intensity and mechanical properties of the glasses are all decreasing constantly, and the optical band gap of the glasses is increasing on the contrary. Moreover, the optical band gap value and Raman spectroscopy of SAM-4 all prove that the number of oxygen bonds in the bridge reach the maximum and the highest structural stability is achieved, which further shows that it is an important reason why its mechanical properties is significantly improved.
研究领域:
材料科学
·
玻璃科学
·
光谱学
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2025
·
IF 9.1
Yongyuan Deng,Yichao Ye,Tao Yin,Zhipeng Tian,Chao Wang,Ying Chen,Zhi Yang,Junling Tu,Riyang Shu
Hydrodeoxygenation (HDO) is a common refinery process to convert oxygen-containing lignin pyrolysis oil into high-quality hydrocarbon liquid fuels. In this work, we prepared a core-shell Ru@SiO 2 -Al 2 O 3 catalyst and employed it in the HDO of phenolic compounds and lignin pyrolysis oil. The unique core-shell structure of the catalyst reduces the size of Ru metal particles, which significantly improves the hydrogenation catalytic activity. The high surface area, large pore size, and large pore volume of the SiO 2 shell provide a favorable environment for the substrate transfer during the reactions, meanwhile the doped Al 2 O 3 introduces a substantial number of acid sites for the catalysis of deoxygenation. The synergistic effect between the metal sites and acid sites greatly promotes the HDO reaction efficiency. Under mild conditions of 220 °C and 1 MPa H 2 , Ru@SiO 2 -Al 2 O 3 catalyst achieved a guaiacol conversion of 99.9% and a cyclohexane selectivity of 99.9%. This catalyst also demonstrates an outstanding stability, with catalytic activity little loss after 6 recycles. Furthermore, an efficient HDO performance was obtained in the upgrade of other phenolic compounds and lignin pyrolysis oil. At the temperature of 240 °C, the content of hydrocarbons in lignin pyrolysis oil increased from 15.4% to 92.7%. These results indicate that Ru@SiO 2 -Al 2 O 3 holds significant potential for the efficient HDO refinery, providing a promising avenue for the future biofuel development.
研究领域:
化学工程
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2018
·Vol. 125
·期 1
·199-211
·
IF 1.515
Hao Fang,Yang Yongzhe,Xiong Wei,Liu Pingle,You Kuiyi,Luo He’an
Mesoporous SiO 2 –Al 2 O 3 supported Cr 2 O 3 catalysts were prepared by the sol–gel and impregnation methods. These catalysts were characterized and applied in cyclohexane nitrosation reaction. The effects of the preparation conditions and the catalyst deactivation were studied. The results show that 20% Cr 2 O 3 /SiO 2 –Al 2 O 3 catalyst calcined at 400 °C exhibits not only the larger surface area, smaller particle size, but also the larger amount of Cr 2+ and Brønsted acid sites. These catalysts show good catalytic performances in the cyclohexane nitrosation to ε-caprolactam and could be recycled for several times in this reaction system for the first time. The catalyst of Cr 2 O 3 /SiO 2 –Al 2 O 3 calcined at 400 °C gives 10.8% conversion with 79.9% selectivity to ε-caprolactam.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Feifan Chen,Bo Zhang,Weihao Cai,Nengquan Fan,Yongkang Lu,Luxia Yin,ZeKai Zhang,Wensheng Ning
Ag/SiO2–Al2O3 aerogel composites with different molar ratio of Si to Al were prepared by the sol–gel synthesis followed by drying under atmospheric pressure and then characterized by XRD, FT-IR, BET, SEM, XRF, TG-DTG, and Py-FTIR, respectively. The effect of doping Al on their physicochemical properties and adsorption desulfurization performance was investigated in comparison with Ag/SiO2. The incorporation of Al in Ag/SiO2 resulted in a gradual decrease in the specific surface area, an increase in the actual content of Ag, and an appearance of Brönsted acid centers. The actual content of Ag in Ag/SiO2–Al2O3-n increased first and then decreased with the increase in Al content. Doping Al in Ag/SiO2 led to an improvement in the adsorption capacity and the adsorptive selectivity for thiophene at the presence of toluene and cyclohexene, as well as the solvent washing regeneration performance, attributed to the adsorption of thiophenics on Ag/SiO2–Al2O3-n by π-complexation of Ag(I) and the acid–base interaction of Lewis and Brönsted centers with thiophenics simultaneously, and the increase in the actual content of Ag in the adsorbents. Ag/SiO2–Al2O3-100 had the largest adsorption capacity for thiophene and benzothiophene, 12.2 mg of S/gads (0.57 mmol of S/mmol of (Ag + Al)) and 17.7 mg of S/gads (0.53 mmol of S/mmol of (Ag + Al)), respectively.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Zihua Lei,Wenjun Yu,Le Fu
Transparent or translucent ceramics typically exhibit inferior mechanical performance, which restricts their wider application. Here, we aim to develop ZrO 2 –SiO 2 –Al 2 O 3 ternary ceramic nanocomposites (TCNCs) that integrate those two often incompatible properties via microstructure engineering. A fixed ratio of 30 mol% SiO 2 was introduced into the ZrO 2 –Al 2 O 3 system, while the ratios between ZrO 2 and Al 2 O 3 were varied. Additionally, different forms of Al 2 O 3 (crystallization or amorphous) were used, resulting in four types of TCNCs. Among the samples studied, the TCNC containing 60 mol% ZrO 2 and 10 mol% amorphous Al 2 O 3 achieved high translucency and remarkable mechanical properties. The TCNC comprised ZrO 2 nanoparticles embedded in SiO 2 glass matrix and Al 2 O 3 glass domains. The superior properties of the TCNC can be attributed to its nanocrystalline-amorphous dual-phase microstructure. For TCNCs utilizing α-Al 2 O 3 submicron particles as the aluminum source, despite their adequate mechanical properties, the agglomeration and lack of densification of these particles resulted in significant light scattering, rending the TCNCs opaque. This study demonstrates that engineering a nanocrystalline-amorphous dual-phase microstructure is an effective strategy to achieve a synergistic combination of robust mechanical properties and high translucence.
研究领域:
材料科学
·
陶瓷研究
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Yongde Ma,Rengan Liang,Wenquan Wu,Jiayin Zhang,Yanning Cao,Kuan Huang,Lilong Jiang
Developing catalysts with not only hydrogenation activity but also cracking activity is very important for the advancement of suspended-bed hydrocracking technology. Within this respect, MoS 2 /SiO 2 -Al 2 O 3 bifunctional catalyst is a kind of typical catalysts with both hydrogenation and cracking activity. Herein, a series of Zr-doped SiO 2 -Al 2 O 3 mixed oxides were synthesized by a sol-gel coupled with hydrothermal method. The synthesized mixed oxides were characterized for chemical structures and acidic properties. It is found that doping SiO 2 -Al 2 O 3 with Zr atoms significantly increases the numbers of acidic sites. The Zr-doped SiO 2 -Al 2 O 3 mixed oxides were then combined with dispersed MoS 2 , which was in-situ produced from oil-soluble Mo precursors, to fabricate a novel kind of bifunctional catalysts for suspended-bed hydrocracking of heavy oils. Owing to the significantly increased numbers of acidic sites in Zr-doped SiO 2 -Al 2 O 3 mixed oxides, corresponding bifunctional catalysts demonstrate much enhanced activity for suspended-bed hydrocracking of heavy oils in relative to MoS 2 /SiO 2 -Al 2 O 3 bifunctional catalysts.
研究领域:
催化
·
化学工程
·
石油炼制
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2020
·
IF 4.551
Jipeng Meng,Chuang Li,Xiao Chen,Chengye Song,Changhai Liang
Synthesis of highly-crystallized ZSM-48 zeolite with low SiO 2 /Al 2 O 3 ratio was successfully performed via seed-assisted route. The influence of various factors on the seed-assisted synthesis was investigated systematically, including the seeds dosages, different seeds species, adding order of seeds, hydrothermal temperature and time, silica and aluminum sources, and gel compositions. The crystallinity, morphology, textural and acidic properties of ZSM-48 were characterized by various techniques, such as XRD , SEM, FTIR, Py-IR, N 2 physisorption , 29 Si and 27 Al MAS NMR. Aluminum sources posed a critical influence on the crystallinity with NaAlO 2 more beneficial to obtain well-crystallized ZSM-48, whereas the crystallinity seemed slightly susceptible to silica sources. SEM results revealed that the crystal size was significantly reduced from ca. 20 μm to around 2 μm after introduced the seeds. Kinetic analysis suggested that the added seeds can significantly reduce the apparent activation energy of nucleation and crystallization, encourage the formation of crystal nuclei and promote crystallization. The Pt-supported seed-assisted samples exhibited considerably higher density of acid sites than that loaded on seed-free sample. The hydroisomerization of n -hexadecane was investigated over various Pt-supported catalysts, and the Pt-supported seed-assisted samples exhibited the highest i-C 16 yield of ca. 75 wt% at conversion over 87 wt%.
研究领域:
催化
·
材料科学
·
化学工程
✓ 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）