ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Qiyan Ji,Li Zhang,Xiuling Jiao,Dairong Chen
Alumina aerogels are desirable for lightweight and highly efficient thermal insulation. However, they are typically constrained by brittleness and structural collapse at high temperatures. The manufacture of alumina aerogels with ultralow thermal conductivity and excellent thermal stability at high temperatures beyond 1300 °C is still challenging. Herein, alumina aerogels with superior ultrahigh-temperature-resistant and thermal insulation were successfully prepared by assembling the α-Al2O3 nanosheets with silica sols as the high-temperature binders. Benefiting from the generation of the mullite-covered alumina biphasic structure, the α-Al2O3 nanosheet-based aerogels (ANSAs) exhibit excellent thermal and chemical stabilities even after calcination at as high as 1600 °C. The ANSAs had a low thermal conductivity (0.029 W·m–1·K–1 at room temperature), structural stability with a measured compressive strength of 0.6 MPa, and good thermal shock resistance. Furthermore, the 2D α-alumina@mullite core–shell sheets were also prepared as assembly units to construct aerogels (AMSAs). This core–shell structure can improve temperature resistance through inter-lattice suppression under continuous energy input at high temperatures. The AMSAs have a linear shrinkage of only 2.7% after calcination at 1600 °C for 30 min, further improving the temperature resistance, making them an ideal super-insulating material for applications at extremely high temperatures.
研究领域:
材料科学
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热力学工程
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产品关联
DOI
PubMed
高影响因子
CRYSTENGCOMM
·
2022
·Vol. 24
·期 10
·1859-1865
·
IF 3.756
Shouzhen Li,Fan Wu,Xuan Zhang,Guangting Han,Yang Si,Jianyong Yu,Bin Ding
Developing ceramic materials for thermal insulation is vital for various applications. However, ceramics have been considered intrinsically rigid and brittle due to the limited crystallographic slips and structural collapse during service. Their lack of flexibility has hampered many high-end applications of ceramic materials. We developed flexible Al2O3/ZrO2 nanofibrous membranes via sol–gel electrospinning and calcination. Al2O3/ZrO2 nanofibrous membranes had flexibility from −196 °C to 1300 °C and low thermal conductivity (∼0.03166 W m−1 K−1 at room temperature). They also supported 1350-times their weight without suffering structual damage. Hence, Al2O3/ZrO2 nanofibrous membranes could be used for thermal insulation in aerospace and industrial fields, and even in harsh environments.
研究领域:
材料科学
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热工程
·
纳米技术
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 67
·54757-54761
·
IF 3.84
Songjie Fan,Shan Wu,Jianhua Liu,Dan Liu
The synthesis conditions of MIL-120 membranes supported by a-Al2O3 hollow ceramic fibers (HCFs) were studied systemically. The continuous and compact MIL-120 membranes were successfully synthesised by secondary growth with in situ seeding step. The MIL-120 membrane shows the separation factors of H2–CO2, H2–CH4 and H2–N2 are 9.4, 7.9, and 7.3 respectively at 293 K and 1 bar with H2 permeance of 3.5 × 10−7 mol m−2 s−1 Pa−1 as well as high thermal stability.
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
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Junji Chen,Mengqin Yao,Qizhuang Zou,Peng Chen,Fei Liu,Tianxiang Zhao
An effective strategy synthesis of Rh/meso-Al 2 O 3 catalysts was demonstrated by mechanochemistry for hydrolytic dehydrogenation of ammonia borane (AB). These catalysts are characterized systematically by N 2 adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results show that the turnover frequency (TOF) and activation energy ( E a ) are 246.8 mol H2 ·mol Rh −1 ·min −1 and 47.9 kJ mol −1 for hydrolytic dehydrogenation of at 298 K catalyzed by Rh/Al 2 O 3 -CTAB-400, obviously higher than those previously reported catalysts. Furthermore, catalyst Rh/Al 2 O 3 -CTAB-400 can be recycled by simple centrifugal separation and the catalytic activity is still well maintained after five cycles. In addition, a plausible mechanism for hydrolytic dehydrogenation of AB has also been proposed. This mechanochemical synthesis method exhibits great application prospects for the preparation of heterogeneous catalysts .
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Wenju Tao,Jiaxin Yang,Liyu Chen,Yifan Zhang,Shaohua Wu,Jiaming Li,Zhaoshun Liu,Jingui He,Zhaowen Wang
Green and efficient recovery of solid waste from aluminum electrolysis is of great significance. In this study, the sediment generated by aluminum electrolysis at the bottom of the waste tank was used as an alternative F resource. A new process of low-temperature acidification roasting with Al 2 O 3 as the catalyst was performed to effectively recover F. The results of the single-factor experiment showed that a long reaction time and high acid-material ratio were conducive to improving the extraction rate of F. Under the conditions of 275 °C and 5 doses of sulfuric acid, the optimum F extraction rate was realized by roasting for 4 h with 1 dose of Al 2 O 3 as the catalyst. The results of the XRD, SEM and chemical analyses showed that NaAl(SO 4 ) 2 was the main component produced in the calcination reaction using Al 2 O 3 as the catalyst, rather than NaHSO 4 (produced in the calcination process without a catalyst). This ensured complete combination of H and F, which greatly improved the extraction rate of F (from 80.76 to 99.76%). The proposed mechanism can provide not only an optimization scheme for the roasting of waste sediment at the furnace bottom, but also a more effective recovery treatment for the acidification roasting of other solid wastes with low Al 2 O 3 content.
研究领域:
环境科学
·
冶金工程
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 3.7
Yutong Pan,Pengju Gao,Shixiong Tang,Xiaoyu Han,Ziwen Hao,Jiyi Chen,Zhenmei Zhang,Heng Zhang,Xiaohui Zi,Maoshuai Li,Shiwei Wang,Yue Wang,Xinbin Ma
This work synthesized a series of Ni/CeO 2 /Al 2 O 3 catalysts with varying CeO 2 doping amounts to enhance low-temperature CO 2 methanation. The introduction of CeO 2 weakens the interaction between Ni and Al 2 O 3 , leading to the formation of Ni-CeO 2 active sites. This results in a high dispersion of Ni and CeO 2 , improved catalyst reducibility, increased number of active sites, and enhanced the CO 2 methanation. This work further investigated the impact of WHSV and catalyst stacking configuration to enhance the reaction. When the catalyst is stacked into three segments with a temperature gradient of 330 °C, 300 °C, and 250 °C under WHSV=9000 ml·h –1 ·(g cat) –1 , the CO 2 conversion significantly increases to 95%, which is remarkably close to the thermodynamic equilibrium (96%).
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
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
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DOI
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Hongqin Ma,Yanan Guan,Wenyao Chen,Zhijun Sui,Gang Qian,De Chen,Xinggui Zhou,Xuezhi Duan
In this work, the support effects on vapor-phase aldol condensation of methyl acetate (MeOAc) with formaldehyde (HCHO) over cesium catalysts are understood by the employment of Al 2 O 3 with different morphologies and crystal phases. The structural and electronic properties of these supported Cs catalysts are characterized by multiple techniques, such as XRD, HAADF-STEM, EDS-mapping, XPS, NH 3 -TPD and CO 2 -TPD. The Cs species are found to be highly dispersed on the Al 2 O 3 surfaces, and their compositions vary with the identity of Al 2 O 3 . A combined catalyst characterization and testing results indicates a balance between acidic and basic sites, i.e., an acid-base synergy, for the production of MA: the excess acidic sites lead to the lower MA selectivity due to the promoted further condensation, while the excess basic sites with the lower MeOAc conversion due to the insufficient activated HCHO species. These insights could be valuable for the design and optimization of catalysts for this reaction.
研究领域:
催化化学
·
材料科学
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产品关联
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
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产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Bowen Wu,Yixi Chen,Mingtai Liu,Yi Tang,Gengfeng Zheng,Linping Qian
The surface properties of CoMg/Al 2 O 3 were evaluated in the aerobic oxidation of p -cresol. The surface interaction is enhanced greatly after Co and Mg impregnation with the mole ratio of Co/Mg from 2 : 1 and 2 : 3. The strongest interaction for the nonpolarity and benzene ring was found on CoMg/Al 2 O 3 with Co/Mg of 2 : 3. But for the interaction with p -π group bonding with negative anion, the highest value appears on the catalyst with the Co/Mg of 2 : 2. In aerobic oxidation of p -cresol, the conversion is significantly increased with Co addition and reaches around 60 % after 24 h' reaction at 338 K. The highest selectivity of p -hydroxybenzaldehyde of 99 % is achieved on Al 2 O 3 with the co-impregnation mole ratio of Co/Mg of 2 : 2. It is suggested that medium adsorption of the reactants and strong stabilization of the intermediates facilitate the aerobic oxidation of p -cresol to p -hydroxybenzaldehyde.
研究领域:
催化化学
·
材料科学
·
有机化学
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产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2025
·Vol. 155
·期 4
·1-8
·
IF 2.4
Zhang Qian,Li Yuanzheng,Pan Zhengyi,Wang Guang-Hui
Catalytic transfer hydrogenation (CTH) of α , β -unsaturated aldehydes to α , β -unsaturated alcohols over metal oxide catalysts is of potential for industrial application. Herein, we have developed a Ni/f - Al 2 O 3 catalyst comprising atomically dispersed Ni δ + (2 < δ < 3) species on porous leaf-like Al 2 O 3 , over which a > 97% yield of furfuryl alcohol (FOL) from CTH of furfural (FFR) is obtained with a turnover frequency (TOF) of 216 h − 1 . Most importantly, the catalyst can be recycled at least 6 times without obvious loss of activity. Its superior catalytic performance can be attributed to the abundant and stable Ni δ + -type acid-base pairs on the surface of Ni/f - Al 2 O 3 .
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
Membranes
·
2024
·Vol. 14
·期 5
·117
·
IF 3.3
Yuqi Song,Kai Miao,Jinxin Liu,Yutang Kang,Dong Zou,Zhaoxiang Zhong
Membrane distillation (MD) is considered a promising technology for desalination. In the MD process, membrane pores are easily contaminated and wetted, which will degrade the permeate flux and salt rejection of the membrane. In this work, SiC ceramic membranes were used as the supports, and an Al2O3micro-nano structure was constructed on its surface. The surface energy of Al2O3@SiC micro-nano composite membranes was reduced by organosilane grafting modification. The effective deposition of Al2O3nanoflowers on the membrane surface increased membrane roughness and enhanced the anti-fouling and anti-wetting properties of the membranes. Simultaneously, the presence of nanoflowers also regulated the pore structures and thus decreased the membrane pore size. In addition, the effects of Al2(SO4)3concentration and sintering temperature on the surface morphology and performance of the membranes were investigated in detail. It was demonstrated that the water contact angle of the resulting membrane was 152.4°, which was higher than that of the pristine membrane (138.8°). In the treatment of saline water containing 35 g/L of NaCl, the permeate flux was about 11.1 kg⋅m−2⋅h−1and the salt rejection was above 99.9%. Note that the pristine ceramic membrane cannot be employed for MD due to its larger membrane pore size. This work provides a new method for preparing superhydrophobic ceramic membranes for MD.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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