ACS Applied Materials & Interfaces
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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
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2019
·Vol. 48
·期 47
·17499-17506
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IF 4.052
Sihang Cheng,Yanchun Liu,Yingnan Zhao,Xinyu Zhao,Zhongling Lang,Huaqiao Tan,Tianyu Qiu,Yonghui Wang
Aromatic amino compounds are important and universally used chemical intermediates in a wide range of industrial fields. Thus, their production with high efficiency and selectivity under ambient conditions is expected and demanded in modern industry. Herein, a series of superfine CoNi alloy nanoparticles embedded in Al2O3 nanosheet (CoxNi1−x/Al2O3, where x represents the content of Co in the precursor) catalysts was fabricated from CoNiAl-LDH and used to catalyze the tandem dehydrogenation of ammonia borane (AB) and hydrogenation of nitroaromatics to the corresponding amines. Systematic experiments indicate that the composition, size, morphology and catalytic performance of the CoxNi1−x/Al2O3 catalysts can be easily controlled by changing the content of Ni in the CoNiAl-LDH precursor. Particularly, Co0.67Ni0.33/Al2O3 exhibited the best tandem catalytic performance among the six samples. This as-prepared catalyst not only showed a moderate turn-over-frequency value (TOF: 34.5 molH2 molCo0.67Ni0.33−1 min−1 at 298 K without base or additives) and relatively low activation energy (32.4 kJ mol−1) for the dehydrogenation of AB, but also superior catalytic activity (conversion yield reaching up to 100%) and selectivity (>99%) for the tandem reductive transformation of in excess of sixteen types of nitroaromatics to aromatic amines. Density functional theory (DFT) calculations suggest that the construction of the CoNi alloy optimized the electronic structure with respect to the pure component, promoting its activity for AB hydrolysis and nitroaromatics hydrogenation. Finally, the catalyst could be easily recycled using a magnet due to the magnetic properties of the Co0.67Ni0.33 alloy.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER COMPOSITES
·
2024
·
IF 4.8
Rong Liu,Jie Chen,Zhanghao Gong,Lihao Sun,Shengtao Dai,Wei Zhao,Mingshuo Ma,Zhigang Liu
In order to enhance the mechanical performance of carbon fiber/epoxy resin composites (CF/EPs), a series of γ-Al 2 O 3 nanosheet/graphene (AG) composites were prepared by hydrothermal method, and successfully introduced into the carbon fiber (CF) surface via self-assembly process, which significantly improved the interfacial bonding force between CF and EP. Mechanical test results showed that the AG modified CF/EPs exhibited superior properties in interfacial shear strength (IFSS), interlaminar shear strength (ILSS), tensile strengths, and flexural strengths compared with the untreated CF/EPs, which were enhanced by 142.9%, 59.6%, 152.5%, and 40.5%, respectively. This is mainly because AG largely increases the CF surface roughness and penetrates into the matrix to enhance the mechanical interlocking effect, crack deflection effect, and Van der Waals forces between CF and polymer matrix. Briefly, the AG synthesized in this study will provide an experimental validation for the development of high-performance carbon fiber reinforced polymer composites (CFRPs) and exhibit potential application prospects in automotive and other fields. Highlights Graphene effectively inhibits the agglomeration of γ-Al 2 O 3 nanosheet. γ-Al 2 O 3 nanosheet/graphene increases the interfacial properties of CF/EPs. γ-Al 2 O 3 nanosheet/graphene largely enhances the mechanical performance of CF/EPs. The as-prepared AGCF/EPs have potential application in automotive and other fields.
研究领域:
材料科学
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复合材料工程
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产品关联
DOI
高影响因子
ACTA PHYSICO-CHIMICA SINICA
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2017
·Vol. 33
·期 7
·1453-1461
·
IF 0.767
LIU Jing-Wei,YANG Na-Ting,ZHU Yan
We report an efficient catalyst composed of ternary components prepared by inlaying Pd/Co3O4 nanoparticles in alkaline Al2O3 nanosheets for catalytic oxidation of methane. Pd/Co3O4 inlaid in alkaline Al2O3
exhibited a higher ability to break the C-H bond of methane than Pd/Co3O4 supported on SiO2, ZrO2, CeO2, and acidic or neutral Al2O3. Our results show more oxygen vacancies and higher amounts of surface adsorbed oxygen
on the surface of Pd/Co3O4/alkaline Al2O3 than on other catalysts, which is responsible for methane activation and conversion. Further, the Pd/Co3O4/alkaline Al2O3 catalyst can almost restore to its initial
value in the absence of water when 5% (volume fraction) vapor water was cut off, although a decrease in activity occurred when water vapor was introduced to the reaction system. Even under a condition similar to the exhaust of a lean-burn natural gas engine, the catalytic performance of the
Pd/Co3O4/alkaline Al2O3 catalyst is excellent, that is, methane could be completely converted when the sample temperature in the reaction atmosphere was ramped to 400°C.
研究领域:
化学
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环境科学
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材料科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
·
IF 22.1
Ding Liu,Zhenkun Su,Bo Han,Kaisheng Xia,Chenggang Zhou,Qiang Gao
Cobalt–aluminum oxide clusters-embedded γ-Al 2 O 3 nanosheets (CAO@AO) were facilely fabricated and developed for peroxymonosulfate (PMS) activation. Interestingly, the Al–OH-rich amphiphilic surface of CAO@AO endowed the catalyst with unique interfacial pH-buffering property, which stabilized the reaction media at nearly neural level and thus prevented the cobalt sites from leaching. Moreover, the presence of Al–OH groups around the Co−Al oxide clusters facilitated the activation of PMS and the redox cycle of Co 2+ /Co 3+ , which resulted in a boosted catalytic activity. Consequently, the CAO@AO exhibited zero leaching of cobalt and high efficacy for PMS activation, enabling complete and ultrafast removal of metronidazole with a significantly higher turnover frequency (TOF, 1.83 min −1 ) than that of Co 3 O 4 (0.004 min −1 ). It was also demonstrated that introducing suitable foreign metal into CAO@AO could further enhance the catalytic activity (e.g., TOF of Mn(40%)-CAO@AO: 5.80 min −1 ). Furthermore, Mn(40%)-CAO@AO-decorated granular support was synthesized that dominated a continuous-flow degradation in column reaction system.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Small Methods
·
2025
·
IF 9.1
Yaping Wang,Tingshi Zhang,Xinlian Huang,Yurong Zeng,Siyuan Wei,Zanyong Zhuang,Chongbing Zhu,Yan Yu
Herein, a versatile amorphous-to-crystalline transformation (ACT) strategy is described, to furnish various metals (Cu, Co, Ni, Cs, and Y) based atomically dispersed catalysts (ADCs) on thin holey 2D Al 2 O 3 . This approach, which involves adjusting reactant stoichiometry, enables the continuous modulation of particle size of ADCs at an atomical level, giving the ultrafine products as single atom, cluster, or nanoparticle catalysts. This synthesis method allows a straightforward analysis and comparison of the reactivity of the ADCs catalysts based on the dispersion of the active metal. In the case of Cu, the cluster catalyst 0.2-Cu/Al 2 O 3 outperforms the single atom catalyst 0.1-Cu/Al 2 O 3 and the nanoparticle catalyst 0.3-Cu/Al 2 O 3 in the oxidation of refractory organic molecules, thanks to its superior electron transport and surface adsorption properties. These findings are well supported by the Density functional theory (DFT) calculations. Additionally, this method facilitates the preparation of atomic clusters with a very small size of 0.5–1 nm, composed of just a few atoms, as exemplified by Ni-based ADCs. The developed synthesis enriches the library of ADCs and demonstrates the potential of amorphous-to-crystalline transformation in creating advanced ultrasmall functional materials.
研究领域:
材料科学
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催化化学
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理论计算
✓ 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）