JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Suwen Li,Gang Wang,Keqiang Zhang,Xueqin Zhang,Lu Zhang,Wenqing Wang,Rujie He
In this paper, Al 2 O 3 functional gradient structures (FGS) were prepared by digital light processing-based 3D printing , and Al 2 O 3 /Al interpenetrated FGS was subsequently obtained by melt infiltrating. The microstructure of Al 2 O 3 FGS and Al 2 O 3 /Al interpenetrated FGS was studied. And the mechanical properties of Al 2 O 3 FGS and Al 2 O 3 /Al interpenetrated FGS under quasi-static compression loading were investigated in detail. Compressive strength , Young’s modulus, and energy absorption of Al 2 O 3 FGS and Al 2 O 3 /Al interpenetrated FGS were experimental tested, compared, and discussed. The failure behavior of Al 2 O 3 FGS and Al 2 O 3 /Al interpenetrated FGS was analyzed by experiments and FEA . This study provides a novel approach for the fabrication of ceramic FGS and ceramic/metal interpenetrated FGS with high mechanical performance.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2023
·
IF 8.7
Lei Liang,Xianxian Sun,Yuanhao Ning,Shasha Wang,Weilong Yin,Yibin Li
The process of toughening brittle ceramics is challenging but important for broadening their range of applications. Extensive studies on toughening brittle alumina (Al 2 O 3 ) ceramics at room temperature have been conducted; however, significantly increasing their toughness at high temperatures remains a challenge. Here, we propose the use of two-dimensional Ti 3 C 2 T x MXene ceramics with high thermal stability to effectively toughen Al 2 O 3 ceramics at high temperatures via a nacre-like structure strategy. The fracture toughness (K Jc ) of the as-prepared MXene/Al 2 O 3 nanocomposite at 1000 °C is 6.02 MPa m 1/2 , 2.4 times that of pure Al 2 O 3 (2.51 MPa m 1/2 ). Moreover, it maintains relatively high strength at 1000 °C (∼193 MPa). The toughening mechanisms - crack deflection, bifurcation and bridging effects - are obtained via in situ observation of crack propagation and finite element simulation. Our novel strategy provides a universal solution to improve the toughness of brittle ceramics at high temperatures and in some special environments.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Lei Wang,Haiyan Liu,Yu Fan,Pei Yuan,Deqi Huang,S. Ted Oyama,Tinghai Wang,Xiaojun Bao
In alumina-based catalysts the properties of the alumina support directly influence the structure (size, morphology, orientation, etc.) of the resulting active phase and ultimately determine the performance of the final catalysts. This paper presents a facile and efficient method for γ-Al 2 O 3 to simultaneously expose {111} facets with strong acidity and {110} facets with moderate basicity. It is shown that the metal oxides NiO x and MoO x can be selectively deposited and subsequently sulfided on the respective facets to form a NiS 2 -MoS 2 /Al 2 O 3 catalyst with substantially enhanced activity for thio-etherification reaction. By cooperative action of the active sites on the newly exposed facets, the catalyst is shown to have superior activity over a conventional NiMoS/Al 2 O 3 catalyst in the thio-etherification reaction between ethanethiol and isoamylene (2-methyl-2-butene) to yield ethylamyl thioethers. Our findings show that tuning the physicochemical properties via crystal facet engineering and inducing cooperative catalysis via preferential deposition of active metals open a novel avenue for the rational design and synthesis of high performance catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
RARE METALS
·
2018
·Vol. 38
·期 1
·1-13
·
IF 1.5
Liu Qi,Wang Wen-Qiang,Yang Yue,Liu Xue-Gang,Xu Sheng-Ming
Aluminum recovery is a key issue for the overall recycling of valuable metals from spent catalysts. This paper focuses on the recovery and regeneration of alumina with high additional value from the spent hydrodesulfurization catalyst CoMo/Al 2 O 3 . The results indicate that 98.13% alumina is successfully leached from the treated spent catalysts by an alkaline leaching process under the conditions of 5 mol·L −1 sodium hydroxide, a liquid/solid ratio of 20 ml·g −1 , a temperature of 160 °C and a reaction time of 4 h. In the leaching residue, no difficult leaching compound is found and cobalt and nickel are enriched, both of which are conducive to the subsequent metal recovery step. The reaction order of aluminum leaching is 0.99. This reaction fits well with the interfacial chemical reaction model, and its apparent activation energy is calculated as 45.50 kJ·mol −1 . Subsequently, γ-Al 2 O 3 with a high specific surface area of 278.3 m 2 ·g −1 , a mean size of 2.2 μm and an average pore size of 3.10 nm is then regenerated from the lixivium, indicating its suitability for use as a catalyst carrier. The recovery and regeneration of alumina from spent catalysts can not only significantly contribute to the total recycling of such hazardous spent catalysts but also provide a new approach for the preparation of γ-Al 2 O 3 with a high specific surface area using spent catalysts as the aluminum sources.
研究领域:
化学工程
·
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Junjie Lu,Dong Wang,Keqiang Zhang,Suwen Li,Bin Zhang,Xueqin Zhang,Lu Zhang,Wenqing Wang,Ying Li,Rujie He
To obtain both plasticity and toughness of the material at the same time, various manufacturing techniques of ceramic-metal composites and structures have been studied. In this work, a bio-inspired Al 2 O 3 ceramic scaffold with Gyroid structure was designed and prepared by stereolithographic (SL) additive manufacturing , then the Al 2 O 3 /Al ceramic-metal hybrid structure was prepared by infiltrating molten Al into the Al 2 O 3 ceramic structure. The performances of the Al 2 O 3 ceramic scaffold and the Al 2 O 3 /Al ceramic-metal hybrid structure were compared and analyzed by a quasi-static compression experiment. The quasi-static compressive strength of the pristine Al 2 O 3 scaffold was 14.36 MPa, while that of the Al 2 O 3 /Al ceramic-metal hybrid structure was up to 89.06 MPa. Moreover, the plasticity of the Al 2 O 3 /Al ceramic-metal hybrid structure was much higher than that of the Al 2 O 3 scaffold. During compression, the Al 2 O 3 /Al ceramic-metal hybrid structure had excellent energy absorption, reaching up to 2569.16 KJ/m³, 15 times that of the Al 2 O 3 scaffold. Therefore, this method can obtain materials with excellent ductility and toughness.
研究领域:
材料科学
·
制造工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2018
·
IF 2.606
Zhuang Lu,Limeng Liu,Zhaoping Hou,Biao Zhang,Guihong Geng,Yujin Wang,Feng Ye
TaC-Al 2 O 3 composites were prepared by hot pressing. Influence of Al 2 O 3 content ranging from 10 to 40 vol. % on densification, phase composition, microstructure, mechanical properties and oxidation behavior of the TaC-Al 2 O 3 composites was investigated. With 30 and 40 vol. % Al 2 O 3 addition a closed porosity was achieved. The Al 2 O 3 particles were uniformly distributed among TaC grains retarding grain growth and resulting in refined microstructures with grains below 2 μm in size. The most densified composite with 40 vol. % Al 2 O 3 addition exhibited good mechanical properties with a Vickers’ hardness of 17.8 GPa, a flexural strength of 485 MPa and a fracture toughness of 5.4 MPa·m 1/2 . After holding at 700°C for 3 h in air, the dense 30 and 40 vol. % Al 2 O 3 compositions showed hardly noticeable and mainly surface oxidation, whereas less densified TaC-Al 2 O 3 composites with 10 and 20 vol. % Al 2 O 3 content and with open porosity were disintegrated to powders.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2023
·Vol. 69
·期 7
·e18070
·
IF 3.7
Jianan Zhang,Min Zhao,Zhi-wen Yin,Zhi-yi Hu,Yanan Liu,Yufei He,Dianqing Li
Modification of rare earth elements (Ln) often contributes to the improved performance in many applications compared with the monometallic catalysts, but the current research is only limited in the individual light rare earth elements. In this work, a series of Ln elements involving Gd, Sm, Nd, Pr, and La was added into monometallic Ni/Al 2 O 3 system to focus how the microstructure of active Ni centers depended on the presence and contents of Ln, and thus improved the catalytic behavior in the steam reforming of methane. Enhanced catalytic behavior could be observed over Ln-modified Ni catalysts, among which Ni-Gd/Al 2 O 3 was predicted to be more high-efficient no matter supported on power or spherical Al 2 O 3 catalysts. A combined investigation of XPS with STEM and TPR was carried out over the candidates to reveal the structure-performance relationship. Furthermore, this was further applied to noble metal systems, realizing the benign universality of the modification strategy.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 36
·16750-16759
·
IF 3.591
Yining Zheng,Cundi Wei,Qi An,Jinsheng Yu,Shaonan Xu,Lina Li
The aluminum alloy is used as the aluminum source, together with melamine and cyanuric acid, in a water reaction system to obtain the precursor of Al2O3/g-C3N4 through self-assembly in one step, and then calcined to obtain the Al2O3/g-C3N4 composite photocatalytic material. γ-Al2O3 has a defect site that can accept g-C3N4 electrons and can bind well with g-C3N4. The addition of γ-Al2O3 changed the morphology of g-C3N4 into a damaged tubular structure with many irregular pores. Also, the specific surface area increased to about 1.2 times that of g-C3N4, and the light absorption edge was extended to 500 nm. In addition, the position of the valence band of g-C3N4 was also changed. Compared with g-C3N4, Al2O3/g-C3N4 has better photocatalytic performance, and the degradation rate of dye rhodamine B (RhB) is about 1.70 times that of g-C3N4.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
MODERN PHYSICS LETTERS B
·
2020
·
IF 1.224
Hetian Xia,Yu Zhao,Weili Li,Ruixuan Song,Yulei Zhang,Weidong Fei
Herein, we report the fabrication of UV-active NaNbO 3 /Al 2 O 3 (30 wt.%) ferroelectric heterojunction photocatalyst with enhanced photoelectrochemical activity to Methylene Blue (MB). Pure NaNbO 3 nanorods (NRs) were synthesized by a facile hydrothermal process and NaNbO 3 /Al 2 O 3 composite was prepared by an ultrasonic vibration method. The heterostructures showed a remarkable increase in photocurrent density and the MB degradation ratio reached 88% in the initial 15 min and eventually reached 98.6% in 75 min. The high photocatalytic efficiency is attributed to the ferroelectric polarization of NaNbO 3 with the forming of heterojunction electric fields assisted by Al 2 O 3 . These properties demonstrate that NaNbO 3 /Al 2 O 3 ferroelectric heterojunction photocatalyst shows promising photoactivity and provides an effective method to improve the photocatalytic properties of other ferroelectrics.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 7
·期 2
·466-480
·
IF 5.287
Sijia Liu,Xin Liang,Jie Zhang,Biaohua Chen
Two different kinds of γ-Al2O3 precursors: stick-like ammonium aluminum carbonate hydroxide and willow leaf-like boehmite could be selectively synthesized via a facile hydrothermal method by just adjusting reaction temperature. After heat treatment, γ-Al2O3 with two different morphologies (stick-like and willow leaf-like) were synthesized and used as supports for CoMo hydrodesulfurization catalysts. Fourier transform infrared spectroscopy of pyridine adsorption and NH3-temperature-programmed desorption showed that stick-like γ-Al2O3 (ACH) and willow leaf-like γ-Al2O3 (AOH) exhibited a lower Lewis acidity than commercial γ-Al2O3. X-ray diffraction indicated that CoMo oxidic catalysts supported on ACH and AOH contained more β-CoMoO4 phase. X-ray photoelectron spectroscopy and high resolution transmission electron microscopy revealed that after presulfurization, more CoMoS active sites and multilayered (Co)MoS2 slabs formed on ACH and AOH supports, thereby creating catalysts with a higher hydrodesulfurization activity in the hydrodesulfurization of thiophene and 4,6-dimethyldibenzothiophene.
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
ENERGY & FUELS
·
2022
·
IF 4.654
Xiuhong Zhang,Dong Wang,Xiao Chen,Longwei Meng,Changhai Liang
The hydrogenation of polycyclic aromatic hydrocarbons (PAHs) over highly efficient and stable catalysts to fine chemicals and intermediates for producing chemical materials is an effective approach to realize the high value-added utilization of coal tar and slurry oil. Herein, two kinds of Al2O3-supported Pt and Rh catalysts are synthesized by strong electrostatic adsorption (SEA) and used to catalyze the hydrogenation of anthracene. Compared with the traditional catalysts synthesized by wet impregnation, the Pt/Al2O3-SEA and Rh/Al2O3-SEA catalysts have smaller active metal particle sizes and higher dispersion, which can expose more active centers, showing higher catalytic activity. Interestingly, anthracene may be preferentially adsorbed on the surface of the Pt/Al2O3 catalyst in a parallel manner but on the surface of the Rh/Al2O3 catalyst in a lateral manner, which leads to the different hydrogenation routes. 9,10-Dihydroanthracene is an initial product for the hydrogenation of anthracene, which is rearranged into tetrahydroanthracene and subsequently hydrogenated to symmetrical octahydroanthracene (sym-OHA) over the Pt/Al2O3 catalyst. The high selectivity to sym-OHA (93%) with the conversion of anthracene near 100% can be achieved in the hydrogenation of anthracene at 240 °C and 7 MPa for 10 h. Additionally, due to the strong anchoring effect, the Pt/Al2O3-SEA catalyst shows high stability for six cycles. This work supplies a new tactic to develop high-performance catalysts for selective hydrogenation of PAHs to important monomers for synthesizing chemical materials.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Xiao-Hui Yang,Guo-Hua Zhang
Oxidation behaviors of Al 2 O 3 reinforced MoAlB ceramics prepared by spark plasma sintering were investigated at 800–1200 °C. The results revealed that appropriate addition of Al 2 O 3 facilitated the improvement of oxidation resistance and mechanical properties of MoAlB ceramics. Among them, the composite ceramics with 5 vol% Al 2 O 3 addition possessed reinforced antioxidant properties with the oxide layer thickness being only 1.81 µm for 800 °C and 2.08 µm for 1000 °C after oxidation for 64 h, respectively. MoAlB ceramics added with 10 vol% Al 2 O 3 demonstrated the optimal mechanical properties. However, excessive addition of Al 2 O 3 adversely affected both the antioxidant and mechanical properties.
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
危险品化学品经营许可证（带存储）