JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Jianfeng Li,Wenli Suo,Yuena Huang,Minglin Chen,Haowen Ma,Chuang Liu,Huan Zhang,Kun Liang,Zhengping Dong
The selective hydrogenation of alkynes to alkenes is widely applied in the chemical industry; nevertheless, achieving highly selective hydrogenation with high catalytic activity is considerably challenging. Herein, ultrafine PdCu bimetallic nanoparticles encapsulated by high-surface-area mesoporous α-Al 2 O 3 were prepared by high-temperature calcination–reduction using a porous organic framework (POF) as the template. As-obtained PdCu@α-Al 2 O 3 exhibited a high selectivity of 95% for the semi-hydrogenation of phenylacetylene as a probe reaction under mild reaction conditions. The separation of continuous Pd atoms and modification of the Pd electronic state by Cu atoms suppressed β-hydride formation and alkene adsorption, contributing to high selectivity for the catalytic hydrogenation of alkynes. The catalytic activity was maintained after 7 cycles due to the strong interaction between the PdCu bimetallic nanoparticles and α-Al 2 O 3 as well as the encapsulation effect of mesoporous α-Al 2 O 3 . Thus, the current work provides a facile strategy for fabricating high-surface-area mesoporous α-Al 2 O 3 -supported catalysts for industrial catalysis applications.
研究领域:
化学工程
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材料科学
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催化反应
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DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Haiping Zhou,Gang Wang,Liping Wang,Zhenhua Zhang,Huiliang Hou,Qifan Zhong,Jin Xiao
Industrial alumina was used as raw material in the high-temperature calcination process, and AlF 3 was introduced to promote mass transfer in the gas phase. The calcination environment, such as sealing, calcination temperature, and holding time, was analyzed to enhance the effect of AlF 3 to promote the crystal growth of alumina. Here, round-like flake α-Al 2 O 3 with an average particle size (D50) of about 18–38 μm were obtained at low dosages (0.1–0.4 wt%) of AlF 3 . The morphology and particle size of α-Al 2 O 3 were further adjusted by introducing different types of micron-scaled nuclei as template inducers. Round-like flake and spherical-like large single crystals α-Al 2 O 3 with an average particle size greater than 35 μm were obtained, respectively, with 65 wt% of 15 μm flake and 10 μm bulk α-Al 2 O 3 nuclei added. In addition, the regulation mechanism of AlF 3 and nuclei on alumina crystal growth was also discussed. Finally, a theoretical basis and technical support for preparing high-performance, low-cost, and high thermal conductivity alumina fillers was provided.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 6
·1333
·
IF 3.057
Xiangjin Guo,Zhaoliang Xing,Shiyi Zhao,Yingchao Cui,Guochang Li,Yanhui Wei,Qingquan Lei,Chuncheng Hao
This paper describes the effects of α-Al2O3nanosheets on the direct current voltage breakdown strength and space charge accumulation in crosslinked polyethylene/α-Al2O3nanocomposites. The α-Al2O3nanosheets with a uniform size and high aspect ratio were synthesized, surface-modified, and characterized. The α-Al2O3nanosheets were uniformly distributed into a crosslinked polyethylene matrix by mechanical blending and hot-press crosslinking. Direct current breakdown testing, electrical conductivity tests, and measurements of space charge indicated that the addition of α-Al2O3nanosheets introduced a large number of deep traps, blocked the charge injection, and decreased the charge carrier mobility, thereby significantly reducing the conductivity (from 3.25 × 10−13S/m to 1.04 × 10−13S/m), improving the direct current breakdown strength (from 220 to 320 kV/mm) and suppressing the space charge accumulation in the crosslinked polyethylene matrix. Besides, the results of direct current breakdown testing and electrical conductivity tests also showed that the surface modification of α-Al2O3nanosheets effectively improved the direct current breakdown strength and reduced the conductivity of crosslinked polyethylene/α-Al2O3nanocomposites.Keywords:XLPE/α-Al2O3nanocomposites;electrical properties;breakdown strength;electrical conductivity;space charge;pulsed electro-acoustic method
研究领域:
材料科学
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电气工程
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产品关联
DOI
PubMed
高影响因子
ChemCatChem
·
2017
·Vol. 9
·期 16
·3144-3152
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IF 4.803
Yong Yuan,Shouying Huang,Hongyu Wang,Yifan Wang,Jian Wang,Jing Lv,Zhenhua Li,Xinbin Ma
Graphical Engineered catalysts : A monodisperse nano-Fe 3 O 4 on α-Al 2 O 3 catalyst synthesized by a novel two-step method of thermal decomposition and impregnation shows enhanced activity and stability for the Fischer–Tropsch synthesis to lower olefins. The effects of promoters (K and S) and size are investigated as well. The Fischer–Tropsch synthesis to lower olefins (FTO) is a desirable nonpetroleum-based route to produce basic chemicals. A novel two-step method was applied to synthesize iron-based supported catalysts, which is to prepare nano-Fe 3 O 4 first by thermal decomposition method and sequentially load them on α-Al 2 O 3 by impregnation. TEM and XRD results manifested that the controllable, uniform Fe 3 O 4 nanoparticles are monodispersed on the surface of α-Al 2 O 3 . H 2 -TPR demonstrated that the reduction of Fe species was facilitated because of the weak interaction between Fe species and the support. These superior properties contribute to an enhanced catalytic activity and stability compared with the catalyst prepared by directly impregnating ammonium iron citrate on α-Al 2 O 3 . Then, the effect of promoters was investigated at the same Fe loading and nanoparticle size. The appropriate addition of K could enhance the catalytic activity and suppress the secondary hydrogenation. On the contrary, S has a negative impact on CO conversion and strongly decreases C 5+ selectivity. Particularly, the combination of K and S could obtain more pronounced CO conversion and higher lower olefins selectivity (≈40 %). Furthermore, size effects were explored by precisely tailoring the iron oxide particle size with the Fe loading kept constant. It was found that 12.0 nm nano-Fe 3 O 4 on α-Al 2 O 3 with or without K plus S promoters showed the best catalytic activity among the catalysts with different particle size.
研究领域:
催化化学
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材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Zhichang Bao,Lei Yang,Zhenmin Cheng,Zhiming Zhou
A non-noble NiZn3/α-Al2O3 catalyst was prepared by a urea co-precipitation method, which showed good stability and high selectivity to styrene (ST) (92% selectivity at above 99% conversion of phenylacetylene (PA)). The high selectivity was mainly attributed to the electronic effect of the Ni–Zn alloy. The selective hydrogenation of the C8 aromatic fraction on NiZn3/α-Al2O3 was well described by a Langmuir–Hinshelwood-type kinetic model. The estimated activation energies for the hydrogenation reactions of PA → ST, ST → ethylbenzene (EB), and PA → EB were 70.31, 81.65, and 74.88 kJ/mol, respectively. A reactor model allowing for an intraparticle diffusion-reaction and external mass transfer was further developed to describe the selective hydrogenation of the C8 aromatic fraction on larger NiZn3/α-Al2O3 particles in a fixed-bed reactor. The observed changes in product composition with the reaction conditions were well predicted by the model, and the results demonstrated that phenylacetylene can be completely removed without loss of styrene under certain conditions.
研究领域:
化学工程
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催化化学
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2022
·
IF 9.221
Qianchun Zhang,Yuxian Zhao,Xuan Shang,Shan Tang,Li Jiang,Yun Wu,Qin Zhou,Shiqin Li
Methallyl alcohol (MA), which is a common volatile organic compound, in vapor form can cause respiratory irritation, headache, nausea, and vomiting. Therefore, the development of a highly selective, excellently sensitive, and efficient sensor for rapidly identifying trace MA is essential. In this study, a La 2 O 3 /α-Al 2 O 3 composite with excellent cataluminescence (CTL) activity in the presence of MA was successfully synthesized. The CTL sensor based on as-prepared La 2 O 3 /α-Al 2 O 3 exhibited high selectivity for MA vapor as well as response and recovery times of 1 and 6 s, respectively. Under the optimal conditions for MA detection, the La 2 O 3 /α-Al 2 O 3 sensor exhibited a linear range of 0.0025–0.50 mg/L (correlation coefficient, R 2 = 0.998) and a low limit of detection of 0.61 μg/L at a signal-to-noise ( S/N ) = 3. The La 2 O 3 /α-Al 2 O 3 sensor was also used to determine the MA content in spiked samples and volatile gases generated from a medicine cabinet. Excellent recoveries in the range of 82.5–107% were obtained, with a corresponding relative standard deviation ( n = 5) in the range of 2.1–4.7%. Furthermore, the CTL sensing mechanism was investigated through density functional theory and high-performance liquid chromatography-ultraviolet analyses.
研究领域:
环境科学
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材料科学
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分析化学
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产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
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2020
·
IF 3.408
Yu Chen,Jin Guo,Minyi Lu,Bo Liang
A novel Ni–Fe nanosheets catalyst supported on α-Al 2 O 3 foam ceramic was synthesized by a hydrothermal method and used to obtain multi-walled carbon nanotubes (MWNTs) via the propane partial oxidation . Catalytic performance tests were carried out at 600 °C and atmospheric pressure using a fixed-bed reactor. The synthesized catalysts and carbon materials were analyzed using various characterization methods. According to the field emission scanning electron microscope (FESEM) results, the catalyst morphology was a 3D grid structure consisting of nanosheets 800 nm length and 80 nm width. Additionally, the quantity and quality of the carbon nanotubes were greatly influenced by different oxygen-to-propane molar ratios, defined as the equivalence ratio ϕ (ϕ = 1.5, 1.78, 2). Transmission electron microscope (TEM) images showed that carbon nanotubes over all catalysts were MWNTs. In addition, the thermogravimetric analysis and Raman data showed that a high yield of MWNTs was obtained at ϕ = 1.78, but the accumulated MWNTs at ϕ = 1.5 exhibited a higher degree of graphitization (I D /I G = 0.89) compared with the other two equivalence ratios.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2016
·
IF 2.933
Shuai Zhang,Na Sha,Zhe Zhao
Stereolithography of UV-curable ceramic suspensions can benefit from the preparation of stable, low viscosity and high solid loading ceramic suspensions without yield stress. Appropriately adding dispersants could optimize the rheological behavior to meet the requirements of stereolithography. In this work, short-chain dicarboxylic acids were utilized to modify the alumina particles and achieve well dispersed ceramic suspensions. The maximum adsorption capacities of dicarboxylic acids were determined by the method of High Performance Liquid Chromatography and the mechanism of surface modification and dispersion was also discussed. Dicarboxylic acids’ influence on the rheology behavior was systematically studied. When doses of dicarboxylic acids reach their maximum adsorption capacities, the alumina suspensions would achieve their lowest viscosities and yield stresses. 45 vol% alumina suspension with a viscosity ˂2 Pa s at shear rate 30 s −1 was successfully formulated. A sintering density of 96.5% can be achieved for the sebacic acid-modified alumina UV-curable suspension.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Dazhao Liu,Ting Fang,Kaixuan Gui,Miao Wang,Wengang Zhang,Dongyang Zhang
In this study, α-Al 2 O 3 platelets with controlled size and uniform thickness were successfully synthesized at 900 °C using a molten salt synthesis method. The effects of calcination temperature, holding time, molten salt and additive concentration on the morphology, particle size, and phase composition of α-Al 2 O 3 were systematically investigated. The results revealed that calcination temperature significantly influenced the particle size and platelet morphology, with higher temperatures leading to larger particles and more irregular structures. Prolonged calcination time increased both the diameter and thickness of the platelets. The content of molten salts and Na 3 PO 4 was critical in regulating platelet uniformity and growth. An appropriate amount of TiCl 4 facilitated the formation of a flake-like structure. This work provides valuable insights into the tailored synthesis of α-Al 2 O 3 platelets, offering a cost-effective method for producing advanced materials with potential applications in various fields.
研究领域:
材料科学
·
无机合成
·
陶瓷工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Zhaowen Ren,Wancheng Zhou,Yuchang Qing,Hui Xie,Shichang Duan,Haijun Pan,Xiaoke Lu,Xia Chai,Di Ran,Yingze Zheng
The Al and H 3 BO 3 mixed powder was introduced into the PCS/Xylene precursor solution as in-situ synthesis α-Al 2 O 3 filler by precursor infiltration and pyrolysis (PIP) method. The in-situ synthesis filler can effectively decrease the open porosity of SiC f /SiC composites and give rise to multiple scattering of microwave and dipolar polarization. Therefore, the mechanical and microwave absorption properties of SiC f /SiC composites can be simultaneously enhanced. The effects of in-situ synthesis filler on the morphologies, flexure strength and reflection loss values of SiC f /SiC composites were investigated. With 2 wt% in-situ synthesis filler, the flexure strength of SiC f /SiC composite was 305 MPa and the maximum reflection loss ( RL m ) can reach − 54.68 dB with the effective absorption band (EAB) of 3.51 GHz in the X band. With 5 wt% in-situ synthesis filler, the flexure strength of SiC f /SiC composite was 207 MPa and the RL m was − 30.91 dB. Due to the inefficient infiltration process, the RL m of SiC f /SiC composites with 10 wt% in-situ synthesis filler was only − 27.36 dB. Nevertheless, the flexure strength of that composite was 259 MPa, owing to the dense matrix. Additionally, the flexure strength of SiC f /SiC composite without filler was 148 MPa and the RL m was − 26.40 dB.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Zhenhao Yang,Guihua Liu,Tiangui Qi,Qiusheng Zhou,Zhihong Peng,Leiting Shen,Yilin Wang,Xiaobin Li
The quality of alumina ceramics generally depends on alumina powder. High-density alumina ceramics were prepared from industrial coarse gibbsite. Near-spheric α-Al 2 O 3 with particles smaller than 500 nm was produced via the synergy of B and F from NH 4 BF 4 . The near-spheric α-Al 2 O 3 calcined at low temperature generated alumina ceramics with high density and low porosity. Meanwhile, the wet pretreatment yielded smaller particles with structural distortion and high microstrain and aluminum hydroxide, notably increasing the relative density of alumina ceramics. 99.18 % relative density, 0.017 % porosity, and 27.54 GPa Vickers hardness of alumina ceramics were achieved at 1650 °C for 2 h without additives and pressed sintering. In addition, the early stage of sintering of alumina green body followed particle boundary diffusion with reduced activation energy in the sintering process. The close packing of the spheric α-Al 2 O 3 , high microstrain of α-Al 2 O 3 , structural defects with considerable AlO 4 units calcined at low temperature, structural distortion in the alumina, and activated alumina on the α-Al 2 O 3 surface collectively promoted the densification of alumina ceramics, achieving remarkable hardness, high density, and tiny porosity.
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Zhiru Xu,Ligang Xu,Yali Wang,Qunyan Li,Suping Cui,Zuoren Nie,Qi Wei
The separation of methyl tertiary butyl ether (MTBE) from aqueous solution by pervaporation-based membrane technology has attracted much attention recently. The present work proposed a novel strategy to enhance the MTBE/water separation performance of porous α-Al 2 O 3 membranes. ZnO seeds were planted on the surface of α-Al 2 O 3 membranes by the deposition and decomposition of zinc acetate, followed by growing ZnO nanorod arrays (ZNA) on the seeded α-Al 2 O 3 membranes by hydrothermal reaction in the mixed hydrated zinc nitrate (HZN) and hexamethylenetetramine (HMTA) solution. Finally, the membranes were hydrophobized by grafting fluoroalkylsilane (FAS) onto their surface. The results show that the MTBE/water separation factor has been dramatically promoted from 7.7 for the α-Al 2 O 3 membranes to 55.7 for the ZNA-covered α-Al 2 O 3 membranes. The promotion may be attributed to the nearly vertically aligned ZnO nanorod arrays, which provide much surface area to load more fluorocarbon groups that are amiable to MTBE molecules and supply a superhydrophobic surface. The MTBE in the permeate mixture has been concentrated to as high as 72.9 wt%, in striking contrast to 4.6 wt% in the feed solution. The obtained membranes are highly stable upon long-term operation.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 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）