Frontiers of Environmental Science & Engineering
·
2017
·Vol. 12
·期 1
·1-7
·
IF 1.716
Shi Jin,Zhang Zihao,Chen Mingxia,Zhang Zhixiang,Shangguan Wenfeng,Gu Shunchao,Shin-ichi Hirano
Fe-BEA catalysts are active for the NH3-SCR of NO. For industrial application, a binder should be added to the Fe-BEA catalysts to make them tightly adhere to the monoliths. The addition of alumina and zirconia as binders to the Fe-BEA led to a different effect on NO conversion. The catalytic activity of the mixed samples was evaluated by the temperature programmed procedure in a flow-reactor system, and the mechanism was analyzed via SEM, BET, XRD and XPS. It was found that larger iron particles were formed by the migration of parent iron particles in the Fe-BEA catalyst with alumina. This led to the increase of Fe 3+ magnitude and iron cluster, enhancing the abilities of NO oxidation and storage. Accordingly, the SCR activity increased slightly in low temperature but decreased sharply in high temperature. For the Fe-BEA with zirconia sample, NO oxidation and storage abilities decreased due to the less iron clusters. The increase of Fe 3+ magnitude resulted in higher catalytic oxidation ability, which gave rise to little change in the SCR activity compared with the Fe-BEA.
研究领域:
催化
·
环境科学
✓ 已验证
DOI
高影响因子
Silicon
·
2024
·
IF 2.8
Huang Yunzhi,Li He,Colombo Paolo
3D printed silica ceramics have the advantages of low thermal expansion coefficient, high thermal stability, easy removal, etc., and are widely used in ceramic core manufacturing. However, in the sintering stage, silica often cracks due to shrinkage and phase transformation, which seriously affects the mechanical properties of the material. The impregnation of alumina sol can promote the formation of cristobalite phase in ceramics, and the mechanical properties of ceramics can be improved with appropriate amount of cristobalite. In this study, 3D printed silica ceramics were impregnated with alumina sol, and the effects of pH value and the concentration of alumina in the sol on the properties of the samples were investigated. When pH was 2.5, the mechanical properties of alumina sol impregnated samples reached a flexural strength of 24.98 ± 0.93 MPa, with a bulk density of 1.70 ± 0.01 g/cm 3 , and an open porosity of 25.82 ± 0.33%. When the ratio of alumina sol to silica sol was 3:1, the mechanical properties of alumina sol impregnated ceramics reached the maximum, with a flexural strength of 33.85 ± 1.69 MPa, a bulk density of 1.73 ± 0.01 g/cm 3 , and an open porosity of 24.02 ± 0.72%.
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
JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Chunlan Li,Wensheng Liu,Yunzhu Ma
In-depth insight into the structure of oligomers in sols plays an important role in determining the structure and properties of the final materials, such as aluminium borosilicate fibers, flakes, microspheres and composites. In this study, the influence of H 3 O + on the structure formation of oligomers in sols prepared from basic aluminium acetate (BAA) was studied by Fourier-transform infrared spectroscopy (FT-IR), 27 Al NMR spectroscopy and density functional theory (DFT) calculation. The results indicated that BAA consisting of tetrahedral Al species existed in dimeric form (BAA2-2). The polymerization of BAA2-2 was more thermodynamically favourable than its hydrolysis both in neutral and acidic solutions. The oligomers formed in neutral aqueous solution were beneficial to prepare different polymers with dendritic or three-dimensional structures. The oligomers formed in acidic solution (H + /BAA = 0.5) were mostly linear tetramers composed of three octahedral and one tetrahedral Al species, which were beneficial to the spinnability of sols during the preparation of ceramic fibers. The addition of H + changed the electronic properties of Al(III) and significantly promoted the coordination ability of water and Al 3+ , leading to an increase in the octahedral Al species and a great change in the structure of the sol. The DFT results were consistent with the experimental results, which provided a necessary theoretical guidance to improve the properties of aluminium sols and meet the needs of the final materials.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE CHINESE CHEMICAL SOCIETY
·
2020
·Vol. 67
·期 6
·1009-1015
·
IF 1.554
Qian Peng,Decun Kong,Li Shi,Xin Wang,Xuan Meng,Naiwang Liu
A new environment-friendly bentonite intercalation composite was successfully obtained from alumina sol intercalation. This process used industrial grade pseudo boehmite as the aluminum source and provided with the advantage of zero emission of acidic wastewater. The bentonite intercalation composite was investigated by XRF, ICP, XRD, FT-IR, BET, and pyridine-FTIR. Results indicated that the basal spacing was enlarged from 14.72 to 15.60 Å; the specific surface area increased by 128%; and the total acid content increased from 65.32 to 245.76 μmol/g. The catalytic activity of this composite was tested by alkylation of aromatics with olefins. The results show that the weak Lewis acid generated by extra-framework aluminum and specific surface area play a decisive role, while weak Brønsted acid site is not the active site for this alkylation reaction.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2016
·Vol. 24
·期 3
·679-683
·
IF 1.385
Li Xueai,He He,Ren Lili
The monolithic hydrophobic mesoporous alumina aerogels were successfully synthesized by acid–base sol–gel polymerization of aluminium chloride hexahydrate (AlCl 3 ·6H 2 O) in deionized water/alcohol solution (v/v = 3:7). To minimize shrinkage during drying, alumina hydrogels were aged in tetraethylorthosilicate (TEOS)/acetonitrile solution, and modified using trimethylchlorosilane (TMCS)/acetonitrile solution. Properties of the final product were examined by contact angle measurement, FTIR, FESEM, TEM and BET analyses. Surface modification was confirmed by FTIR spectroscopy. It was found that hydrophobic property of the alumina aerogels was affected by the contents of TMCS. When the molar ratio of TMCS to AlCl 3 ·6H 2 O is 0.35, hydrophobic alumina aerogels shows lower bulk density (0.453 g/cm 3 ) and higher surface area (495 m 2 /g) than those of unmodified alumina aerogels (0.933 g/cm 3 , 413 m 2 /g).
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Hang Qin,Liangcheng Tong,Qisi Dai,Xinyi Zhou,Zhiwei Liu,Wenming Guo,Pengzhao Gao,Hanning Xiao
α-Al 2 O 3 exhibits excellent physical and chemical stabilities and thus has a wide range of applications in various fields, however the potential application are often called off because of the grains coarsening and vermiculite structures originated from the high-temperature calcination process. In this paper, the calcination temperature has been significantly reduced by selecting the chelating anhydrous aluminium sols as the precursor. It was found that when the chelating agent was malic acid and the addition amount was 0.06 mol, the chelated structure had the highest content of [AlO 6 ] octahedra, which was more favourable for the low-temperature synthesis of α-Al 2 O 3 . Kinetic analysis showed that the activation energy for the conversion of γ-Al 2 O 3 to α-Al 2 O 3 in this work was 398.09 kJ mol −1 , which has been reduced by nearly 100 kJ mol −1 and thus the complete conversion of γ-Al 2 O 3 to α-Al 2 O 3 was achieved by holding at 900 °C for 2 h. The obtained spherical α-Al 2 O 3 nanoparticles, with a particle size of about 67.2 nm and a uniform morphology. After further extending the holding time to 30 h, the complete conversion of α-Al 2 O 3 was achieved at 825 °C, while the initial nucleation temperature was lower than 760 °C.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2020
·
IF 3.724
Xunwen Su,Liqun Zhu,Weiping Li,Haining Chen,Rui Cao,Huicong Liu
Al 2 O 3 -contained zinc coatings with enhanced protective and mechanical performances were prepared on NdFeB magnets by in situ electro-deposition methods from the zinc plating baths containing alumina sol. The positively charged alumina sol particles migrate to the NdFeB cathode and then gel along with zinc on the cathode surface, which changes the electro-deposition process of zinc. As a result, the surface morphology and phase structure of the zinc coating is significantly changed. The incorporation of alumina particles achieves a denser zinc coating with a smaller grain size and the hardness is well improved. By increasing alumina sol concentration in the plating bath, the micro-hardness and wear resistance of the zinc coatings gradually increased. What's more, the alumina sol addition also improved the corrosion resistance of zinc coatings. When 20 wt. % alumina sol is added, the corrosion potential of the zinc coating is positively shifted for 168 mV and the corrosion current was more than one order magnitude lower than the blank one. Therefore, this approach shows great promise to obtain alumina-contained zinc coatings with enhanced anti-corrosion properties and mechanical properties.
研究领域:
材料科学
·
电化学
·
表面工程
✓ 已验证
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 7
·2704
·
IF 3.748
Tao Luo,Yunzhu Ma,Shuwei Yao,Juan Wang,Wensheng Liu
Due to the lack of relevant in situ characterization techniques, the investigation of aluminum sol–gel progress is lacking. In this study, combined with molecular dynamics simulation and conventional experimental methods, the microstructures, rheological properties, and gelation process of the carboxylic aluminum sol system were studied. The experimental results showed that, with the increase in solid content, the microstructure of the colloid developed from a loose and porous framework to a homogeneous and compact structure. The viscosity of aluminum sol decreased significantly with the increase in temperature, and a temperature above 318 k was more conducive to improving the fluidity. The simulation results show that the increase in free volume and the connectivity of pores in colloidal framework structure were the key factors to improve fluidity. In addition, free water molecules had a higher migration rate, which could assist the rotation and rearrangement of macromolecular chains and also played an essential role in improving fluidity. The Molecular dynamics simulation (MD) results were consistent with experimental results and broaden the scope of experimental research, providing necessary theoretical guidance for enhancing the spinning properties of aluminum sol.Keywords:aluminum sol;gelation;alumina precursor fiber;molecular dynamic;rheology
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Xunwen Su,Liqun Zhu,Weiping Li,Haining Chen,Rui Cao,Huicong Liu
Alumina sol was prepared with ascorbic acid (also known as Vitamin C, Vc) as peptizer instead of the traditional used HCl. The prepared sol was then used for the anti-corrosion protection of NdFeB magnets. After substitution, the protective ability of the alumina sol film on NdFeB magnets improved significantly. Systematic comparison of the two alumina sol film were taken. Result showed that the Vc peptized alumina sol (AS-Vc) film showed a more uniform and complete surface which can help repair the defects on NdFeB surface without causing other damages. The electrochemical test showed the corrosion current density of NdFeB with AS-Vc film further reduced to 7.682 × 10 −8 A cm -2 , which is almost one-third of that in AS-Cl film. Along with the salt-water immersion test result, the data showed the corrosion is obviously suppressed after substitution. What’s more, the differences of the film formation mechanism between the two alumina films were investigated. By comparison, NdFeB in AS-Vc showed an about 200 mV more positive open circuit potential than it in HCl peptized alumina sol (AS-Cl), which means less redox reaction during the film formation process. Above all, the Vc peptized alumina sol provides higher corrosion resistance ability for NdFeB, which is wery suitable for the simple protection of NdFeB materials.
研究领域:
材料科学
·
腐蚀与防护
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 16
·2296
·
IF 4.7
Shuai Gao,Zeqi Cao,Kai Liu,Shuning Liu,Wanjun Pang,Hongyi Jiang
To reduce production costs and enhance the high-temperature resistance of SiO2aerogels, an aluminum-doped silica aerogel (ASA) was successfully prepared using the sol-gel method and atmospheric drying method. The composite silica sources included TEOS and inexpensive acidic silica sol, while the aluminum source was aluminum sol. The study investigated the influence of the molar ratio of acidic silica sol to TEOS, Al/Si, and calcination temperature on the composition, structure, and high-temperature resistance of the ASA. The results indicate that a sample with an acidic silica sol to TEOS molar ratio of 0.8 achieved a specific surface area of 683.204 m2·g−1. The Al/Si molar ratio significantly impacted the high-temperature resistance of the ASA, with the sample having a molar ratio of 0.02 Al/Si displaying the highest specific surface area of 705.956 m2·g−1at 600 °C. Moreover, this surface area remained at 273.099 m2·g−1after calcination at 1000 °C, notably higher than the sample without aluminum sol (16.082 m2·g−1). Mechanism analysis indicated that the addition of aluminum sol to the SiO2aerogel inhibited phase transitions, and both acidic silica sol and aluminum sol particles enhanced the aerogel structure, contributing to a marked improvement in high-temperature resistance.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Zhiqiang Dai,Jie Liu,Qizhi Hou,Chengwu Yang,Xueqing Zhang,Manunya Okhawilai,Prasit Pattananuwat,Xinyu Zhang,Jiaqian Qin
The construction of artificial solid electrolyte interfaces on zinc anodes is recognized as an effective strategy to mitigate zinc dendrite formation and side reactions; however, existing methods are often complex and time-consuming. In this study, we successfully fabricated a highly stable Sn–Al sol protective layer on the surface of the zinc anode using a simple spray-coating technique. This protective layer significantly enhances the electrochemical performance of zinc symmetric cells, achieving stable cycling for over 2500 h at 1 mA cm–2. In Zn//Cu half-cells, the Sn–Al sol coating improves charge–discharge efficiency and cycling stability, with over 500 and 950 cycles at 1 and 5 mA cm–2, respectively. The average charge–discharge efficiency during stable cycling reaches 95.7%, in contrast to 85.0% for bare Zn, indicating improved utilization of Zn2+. Additionally, the Sn–Al sol coating offers enhanced corrosion resistance and effectively promotes uniform Zn2+ growth along the (101) crystal plane, reducing dendrite formation. Overall, this simple spray-coating approach presents significant potential for high-stability modifications of zinc anodes, offering a novel strategy for the industrial application of zinc-ion batteries.
研究领域:
材料科学
·
电化学
·
储能技术
✓ 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）