CHINESE JOURNAL OF CHEMICAL PHYSICS
·
2016
·Vol. 29
·期 5
·617-622
·
IF 0.496
Tang Wen-wu,Zhang Xing-hua,Zhang Qi,Wang Tie-jun,Ma Long-long
Ni-based catalysts supported on different supports ( α -Al 2 O 3 , γ -Al 2 O 3 , SiO 2 , TiO 2 , and ZrO 2 ) were prepared by impregnation. Effects of supports on catalytic performance were tested using hydrodeoxygenation reaction (HDO) of anisole as model reaction. Ni/ α -Al 2 O 3 was found to be the highest active catalyst for HDO of anisole. Under the optimal conditions, the anisole conversion is 93.25% and the hydrocarbon yield is 90.47%. Catalyst characterization using H 2 -TPD method demonstrates that Ni/ α -Al 2 O 3 catalyst possesses more amount of active metal Ni than those of other investigated catalysts, which can enhance the catalytic activity for hydrogenation. Furthermore, it is found that the Ni/ α -Al 2 O 3 catalyst has excellent repeatability, and the carbon deposited on the surface of catalyst is negligible.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Hang Qin,Wenming Guo,Xin Huang,Pengzhao Gao,Hanning Xiao
α-Al 2 O 3 nanoparticles with a particle size of ~10 nm were synthesized from aluminum alkoxide precursor chelated by oxalic acid at 500 °C and added to boehmite sol as phase transition seeds (PTS) in low temperature preparation of α-Al 2 O 3 ultrafiltration (UF) membrane. With the PTS doping of 2.5 wt%, a single phase α-Al 2 O 3 membrane with small pore size of 7.2 nm was prepared at 950 °C. After long-term static and dynamic corrosion tests, the as-prepared α-Al 2 O 3 UF membrane was found to no significant degradation in performance, displaying a stable MWCO and water permeability of 15 kDa and 85 L/(m 2 h bar) respectively. In the decolorization of vinegar fermentation wastewater, the COD removal was 63% whereas the color removal could reach 98%. Furthermore, the contaminated membrane could be reused many times after cleaning, confirming the excellent durability and practicality of α-Al 2 O 3 UF membrane in wastewater treatment .
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Chaozhong Wu,Lingjiao Zhan,Haotian Liu,Juan Wang,Wensheng Liu,Shuwei Yao,Yunzhu Ma
Understanding the mechanism of the oriented growth in multi-component alumina-based fibers and inhibiting its progression is crucial for enhancing their thermal stability. In this study, a novel diphasic fiber composed of lamellar α-Al 2 O 3 and mosaic-like mullite grains was prepared. We discussed the oriented growth behavior of lamellar α-Al 2 O 3 grains and the diffusion phenomenon of the Al element in SiO 2 substrate under the combined addition of iron sol and La 2 O 3 , proposing a new mechanism for oriented growth in diphasic fibers. The diffusion of the Si element to the tips of alumina grains contributed to a significant increase in the mobility of non-basal planes, resulting in (0001) surface growth of α-Al 2 O 3 grains. Furthermore, the La segregation at grain boundaries significantly impeded the oriented growth of α-Al 2 O 3 grains, which was critical for improving the thermal stability of multiphase alumina-based fibers.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2021
·
IF 4.094
Xiao Guo,Haibo Wang,Rui Tian,Haojiang Yin,Yunfeng Qiu,Feng Wang
Hydrophobic α-Al 2 O 3 ceramic membrane (HCM) offers excellent mechanical properties , corrosion resistance , and high-temperature resistance. Application of HCM in the membrane distillation (MD) process could expand the application scope of MD equipment and greatly lengthen the replacement cycle of the membrane. Here a prediction model of the contact angle of HCM was constructed by physical-chemical combined modification method, orthogonal method, and stepwise linear regression method to optimize the preparation process of HCM. The surface morphology , contact angle, and surface functional groups of HCM were characterized. In this work, we polished the surface of the α-Al 2 O 3 ceramic membrane with 400 mesh sandpaper to copy the optimal morphology and found that the effect of grafting time on the contact angle of HCM could be abandoned. The optimal levels of drying temperature, drying time, and grafting solution concentration were 250 °C, 65.5 min, and 0.019 mol/L, respectively. The contact angle of HCM was 145.3° corresponding to the optimal preparation process. The significance of the prediction model of the contact angle of HCM was better than 0.05, and all of the prediction errors were less than 5%. This work has an important guiding value for exploiting the optimum hydrophobic property of HCM.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
SOLID STATE SCIENCES
·
2024
·
IF 3.4
Meng-Jie Cui,Imran Muhammad,Jian Feng,Tie-Zhen Ren
The crystal and particle size distribution of α-alumina (α-Al 2 O 3 ) nanoparticles is increasingly important for their potential application. However, it is difficult to produce α-Al 2 O 3 nanoparticles due to the high activation energy barrier making it difficult to obtain a pure α-Al₂O₃. In this paper, α-Al 2 O 3 nanoparticles with an average size of 60 nm in width and about 100–300 nm in length were prepared using isopropanol through thermal treatment at 1200 °C, accompanied by a minor fraction of the θ phase. Addressing the challenge of achieving pure phase α-Al 2 O 3 , Density Functional Theory (DFT) calculation was conducted to explore the energy landscape similarity between the θ and α crystal phases. The results provided valuable insights into obstacles associated with obtaining pure α-Al 2 O 3 , enlightening the relationship between surface electronegativity and crystal phases. Furthermore, X-ray Photoelectron Spectroscopy and electrochemical tests were employed to demonstrate that the α phase could enhance the surface electronegativity of Al 2 O 3 . This comprehensive study not only encompasses the synthesis of Al 2 O 3 nanoparticles but also elucidates the distinctions between α and θ phases. These results offer valuable insights into methods optimizing for the synthesis of pure phase α-Al₂O₃.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2023
·
IF 3.8
Jianhui Su,Yan Liu,Xiujing Peng,Guoxin Sun,Xuchuan Jiang
Due to the high activation energy barrier and the sporadic nature of nucleation, the temperature required for the transition from cubic dense γ-Al 2 O 3 to tripartite α-Al 2 O 3 is as high as 1100–1200 °C. In this work, a two-step strategy was employed to reduce the phase transformation temperature, and prepare α-Al 2 O 3 particles with good dispersion. As the first step, 10 nm sheet γ-Al 2 O 3 was obtained by ammonium aluminum carbonate (AACH) decomposition, which was more favorable to the crystal transformation in the next ball-milling processing. In the second step, γ-Al 2 O 3 powder with partial α-Al 2 O 3 produced in situ by ball-milling γ-Al 2 O 3 was calcined, and α-Al 2 O 3 nanoparticles were obtained at just 850 °C. The content of the α-Al 2 O 3 is determined by the Rietveld Refine method. The relationship between ball-milling time and α-Al 2 O 3 content was clarified, and the effect of α-Al 2 O 3 content on the transformation temperature and morphology of γ-Al 2 O 3 was discussed. The results showed that the α-Al 2 O 3 content rises with the increase of ball milling time, and spherical α-Al 2 O 3 nanoparticles can be obtained when the α-Al 2 O 3 content is 5 %. The addition of α-Al 2 O 3 seeds reduces the phase transition temperature but agglomeration exists. Our proposed two-step low-temperature calcination strategy is an important method for the preparation of alumina nanoparticles
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
ACS Omega
·
2025
·
IF 4.3
Xueni Sun,Qiang Fu,Lidong Li,Chunxiang Huang,Jun Wang,Hui Shao
Experiments and molecular simulations were combined to investigate the adsorption mechanism of dimethyl carbonate (DMC) and methanol (MeOH) azeotrope onto α-Al2O3 while the differences and similarities between pure and azeotropic components were discussed. Static experimental results have shown that α-Al2O3 exhibited capacities in an unexpected order as azeotropic MeOH > pure DMC > pure MeOH > azeotropic DMC. MeOH-DMC and pure MeOH both fitted the PFO model with proximal kinetic constants, while the pure DMC exhibited a different behavior with a diffusion-controlled stage followed by chemisorption. The interfacial configuration as well as the mechanism at the molecular level was studied by molecular dynamics and density functional theory. Molecular simulation results indicate that a multilayer adsorption conformation is formed on the α-Al2O3 (0 0 1) surface for MeOH-DMC with most Al sites being occupied by MeOH followed by DMC constructing a bilayerlike structure with the preadsorbed MeOH molecules. Moreover, the adsorption of DMC can further reduce the dissociation of preadsorbed MeOH. This factor seems to promote the adsorption of more MeOH molecules on the α-Al2O3 (0 0 1) surface, leading to DMC aggregation outside the MeOH layer.
研究领域:
化学工程
·
材料科学
·
计算化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Composites Science
·
2025
·Vol. 9
·期 3
·136
·
IF 3.7
Gang Huang,Chengzhe Gao,Jin Leng,Yang Wu,Liying Chen,Ran Jing,Pengshu Xie,Hua Deng,Qiwu Shi
As the communication band gradually approaches the terahertz (THz) range, there is an urgent need to explore materials with ideal dielectric properties for THz communication devices. Nevertheless, most polymers present a low dielectric constant (Dk), and the regulation of their dielectric properties in the THz range has rarely been reported. In this work, the isotactic polypropylene (iPP)/α-Al2O3whisker composites were synthesized and their THz dielectric parameters were optimized. TheDkvalues increased from 2.23 to 3.13 with filler (α-Al2O3whisker) concentration, ranging from 0 to 20 vol%, but were almost independent of the test frequency. The loss tangent (Df) values presented an increasing tendency along with both filler concentrations and test frequency. All composites exhibitedDfvalues of less than 4.0 × 10−3. Particularly, the dielectric properties of composites can be further regulated by adjusting the orientation direction of the whisker fillers. The orientation of the whisker fillers was adjusted via the injection molding method. Along the direction of the whisker orientation distribution, the composites exhibit higherDkvalues and lowerDfvalues. This work presented a schematic to design polymer composites with higherDkbut controlledDfin the THz range and is significant for the development of advanced materials-based THz devices.
研究领域:
材料科学
·
电子工程
✓ 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
INORGANIC CHEMISTRY COMMUNICATIONS
·
2021
·
IF 2.495
Zhiyuan Wang,Hairu Xiang,Jiawen Zou,Zenghui Mai,Zhenzhen Cao,Mingliang Li,Bingbing Fan,Gang Shao,Hailong Wang,Hongliang Xu,Rui Zhang,Hongxia Lu
Spherical α-Al 2 O 3 particles with the size of 1–2 μm were obtained by microwave hydrothermal(M-H) method and subsequent microwave calcination. In the synthesis, Al 2 (SO 4 ) 3 ·18H 2 O was used as the aluminum sources, and CH 4 N 2 O was used as the precipitant. The effects of M-H temperature, heating preservation time and pressure in the reactor on the morphology, phase composition, particle size and surface area of the particles were studied. The results show that amorphous precursors with high sphericity and good dispersion can be rapidly (30 min) produced by M-H method at low temperature (100 °C). Increasing the temperature or extending the holding time will destroy the spherical morphology of the precursor, while transforming its phase from amorphous to γ-AlOOH. Pressure in the reactor does not change the phase composition of the precursor, but affects its dispersion and homogeneity. The precursor retains its spherical morphology after microwave calcination at 1100 °C for 90 min. The resulting powders were hot pressed and sintered at 1650 °C for 30 min to obtain a high-performance ceramic plate with a thermal conductivity of 27.1 W/(m·K) and a Vickers hardness of 21.4 GPa.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Enrou Mei,Xiaodong Liu,Ya Chen,Yanxia Yu,Zhaoping Chen,Keqin Yang,Xiaojuan Liang,Weidong Xiang
Recently, perovskite has received extensive attention due to their excellent photoelectric properties, while the instability of perovskite quantum dots (PQDs) has always troubled us. Herein, we proposed a simple coating mechanism to protect PQDs. Using oleic acid (OA) for etching α-Al 2 O 3 wafer to make the surface appear pore structure, and the PQDs was coated within the modified α-Al 2 O 3 wafer, thereby improving the stability of PQDs. The CsPbX 3 @α-Al 2 O 3 composite material can achieve the emission of blue-green–red (436 nm to 636 nm) through adjustable luminescence wavelength. The photoluminescence (PL) intensity of CsPbBr 3 @α-Al 2 O 3 composite material exposure to the air after 28 days can maintain over 50%. It is worth noticing that the photoluminescent quantum yield (PLQY) of CsPbBrI 2 @α-Al 2 O 3 composite material can reach 58%, the colour purity of CsPbBr 3 @α-Al 2 O 3 and CsPbBrI 2 @α-Al 2 O 3 achieve 97.1% and 99.8%, respectively. It was due to the high colour purity of the composite materials can the selected CIE colour coordinate monochromatic light encompassed 114% of NTSC colour gamut. Moreover, the warm white light-emitting diode (WLED) yielded bright natural white light and showed the luminous efficiency (LE) of 86.58 lm/W, colour rendering index (CRI) of 86.9, correlated colour temperature (CCT) of 4602 K. The LE and CRI reaches a relatively balanced value, which showed that this composite material has a certain development prospect in the WLED field.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Lingjiao Zhan,Chaozhong Wu,Fuqin Zhang,Juan Wang,Haotian Liu,Yutong Chen,Shuwei Yao,Yunzhu Ma,Wensheng Liu
The coordinated regulation for α-Al 2 O 3 and mullite structures in the alumina-mullite duplex fiber poses a challenging yet crucial task in achieving a fiber with exceptional high-temperature properties. In this study, Fe element was added into the alumina-mullite fibers in the form of iron sol and ferric nitrate solution, respectively, with the aim of obtaining a fiber consisting of fine mullite grains embedded with nano α-Al 2 O 3 grains. The results revealed that the addition of Fe element significantly enhances the crystallization process of mullite in alumina-mullite fibers. Specifically, adding iron sol resulted in the reduce of α-Al 2 O 3 formation temperature to 1300 °C, while introducing Ferric nitrate solution promoted the formation of mullite phase. Simultaneous introduction of 1.3 wt% iron sol and 1.3 wt% Ferric nitrate solution contributed to achieve alumina-mullite fiber with tensile strength of 2.06 GPa. In addition, the influence mechanism of Fe source on the phase transformation and microstructures of alumina-mullite fiber were discussed.
研究领域:
材料科学
·
陶瓷学
✓ 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）