TRIBOLOGY INTERNATIONAL
·
2022
·
IF 5.62
Shuna Chen,Yunfeng Su,Qiuan Sun,Hengzhong Fan,Junjie Song,Litian Hu,Yongsheng Zhang
A fibrous monolithic ceramic was constructed with Al 2 O 3 fiber cells surrounded by Cr 2 O 3 phase-two kinds of brittle ceramics, to achieve an excellent combination of high strength and toughness, which is usually mutually exclusive in engineering materials . The material was demonstrated to fail in a non-brittle fracture manner and showed a typical rising R-curve behavior with the maximum crack growth toughness of 9.05 MPa m 1/2 . Meanwhile, the composite ceramic exhibited excellent tribological performance at high temperatures, with the lowest friction coefficient of 0.29 and wear rate of 1.07 × 10 −5 mm 3 /Nm at 600 °C. It was also demonstrated that the thermal stability of Cr 2 O 3 has a great influence on the wear mechanism when the temperature was above 800 °C.
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高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Lu Lv,Min Zhao,Yanan Liu,Yufei He,Dianqing Li
Alumina (Al 2 O 3 ) is widely used in the chemical industry as the catalyst and support due to its high specific surface area, abundant pore size distribution and chemical stability. However, the occurrence of hydration in water environment, result in outstanding decrease in specific surface area and collapse of pore structure. In this work, dodecyl phosphoric acid (PA) is used to modify the surface of Al 2 O 3 to obtain a series of hydrophobic material (Al 2 O 3 -PA). Based on XPS and NMR analysis, PA is chemically bonded on Al 2 O 3 to form P O Al bond. Furthermore, BET and WCA results display that Al 2 O 3 -1PA exhibits excellent the hydrophobicity and hydrothermal stability while maintains the pore structure. Take it as the substrate to support the Pd nanoparticles , the as-prepared Pd/Al 2 O 3 -PA shows the superior catalytic performance in the hydrogenation of phenol and anthraquinone relative to Pd/Al 2 O 3 , indicating the accessibility of Pd sites after PA modification. Especially, the significantly enhanced stability is also obtained in four cycles for aqueous phenol hydrogenation. This can be ascribed that the PA modification inhibits the aggregation of Pd nanoparticles and the products adhesion in the reaction process. The extension of PA coatings to monolithic catalysts could expand their current capabilities in industrial applications and warrants ongoing investigation.
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高影响因子
ENVIRONMENTAL ENGINEERING SCIENCE
·
2022
·Vol. 39
·期 1
·56-63
·
IF 2.172
Jie Zhang,Ben Dong,Jing Liu,Wuxu Yang,Sijie Ge,Shilong He
In this article, Mn doping on Ce-based γ-Al2O3 (i.e., Mn-Ce-γ-Al2O3) was synthesized and then employed as catalysts to study the removal of phenol from aqueous solutions through catalytic ozonation process. The results showed that the phenol removal was remarkably increased to 97.50% if Mn-Ce-γ-Al2O3 was adopted as the catalyst. In addition, the kinetic rate of the reaction was increased, approximately, about 1.49 times when using Ce-γ-Al2O3 catalyst with Mn doping. Moreover, X-ray diffraction, transmission electron microscopy, Brunner-Emmet-Teller measurements, and X-ray photoelectron spectroscopy techniques were used to comprehensively characterize the physicochemical properties of the synthesized Mn-Ce-γ-Al2O3 catalyst, including the phases, morphologies, textural properties, and dispersity of the surface active species. More uniform channel mesoporous structures were obtained after Mn doping on Ce-γ-Al2O3, which could enhance the gas-liquid mass transfer rate, surface hydroxyl groups, Ce3+/Ce4+ ratio, and the formation of Mn-Ce solid solution. In this study, the effects of Mn doping on Ce-based γ-Al2O3 on phenol degradation were investigated and the removal mechanisms were suggested for a better understanding of the improved removal efficiency.
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International Journal of Applied Ceramic Technology
·
2023
·Vol. 21
·期 1
·427-437
·
IF 2.1
Yulong Wang,Zhoufu Wang,Xitang Wang,Hao Liu,Yan Ma,Pengcheng Jiang,Yunjie Dong,Jiwei Niu
Short carbon fiber is a promising candidate for reinforcing carbon-containing refractories at the macro scale due to its excellent high-temperature stability and mechanical properties. In this work, the microstructure evolution of short carbon fiber and the effect of its addition on the properties of Al 2 O 3 –C refractories are investigated. The results show that adding short carbon fiber could affect the distribution of in situ ceramic phases, combined with the cross-scale reinforcement effect, leading to high strength—the CMOR of short carbon fiber containing refractories could be 23.0% higher than the free ones, while the HMOR could be 22.0% higher. Furthermore, the results suggest that the short carbon fiber containing refractories treated at 1400°C possesses high resistance to the initiation of crack propagation, which could be attributed to the high bonding strength brought by carbon fiber. Noteworthy, adding short carbon fiber could improve thermal shock resistance. The short carbon fiber containing refractories treated at 1300°C could possess a higher residual strength ratio than free ones. For instance, the specimen containing 0.1 wt% short carbon fiber shows the highest residual strength ratio (87.7%).
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高影响因子
Materials Today Communications
·
2023
·
IF 3.8
Lindai Sun,Zexing Liu,Hui Huang,Yang Xia,Yongping Gan,Xinping He,Wenkui Zhang,Jun Zhang
Radiative cooling utilizes high solar reflectivity and high infrared emissivity to achieve temperature cooling down, which has attracted extensive research interest as a zero-energy consumption manner. However, the design of photonic structures and metamaterials for radiative cooling do not exploit commercialization prospects due to high production costs and structural complexity. Here we propose an economical and scalable electrospinning method for fabricating high-performance sun-shading and radiative cooling composite flexible film. The composite film is a non-woven fabric of nanofibers with polymethyl methacrylate (PMMA) and aluminum oxide (Al 2 O 3 ) nanoparticles . The diameter of the nanofibers distributes in the range of 300–1200 nm and Al 2 O 3 nanoparticles are wrapped in the nanofibers. The nanofibers strongly scatter sunlight to enable high solar reflectivity and back-reflection layer is no more necessary. Molecular vibrations of PMMA and phonon polarization resonance of Al 2 O 3 nanoparticles synergistically result in high infrared emissivity. At a thickness of 0.30 mm and with an Al 2 O 3 content of 8%, this material exhibits exceptional solar reflectance levels of approximately 95% between wavelengths of 1.1–2.5 µm. Additionally, it demonstrates an extremely low rate of solar absorption of approximately 5.5% between wavelengths of 0.3–1.1 µm, distinguishing itself as a highly effective solar selective surface even without the inclusion of a back-reflective layer. Furthermore, the material exhibits ultrahigh infrared emissivity levels of approximately 0.98 within atmospheric windows ranging from 8 to 13 µm. These remarkable characteristics position this material as a highly promising candidate for use in solar thermal energy conversion systems. As a result, the device shows a cooling performance that reaches a temperature decrease of up to 4.3 °C under 1000 W/m 2 peak solar intensity and a decrease of 5.9 °C during nighttime. The composite film has enormous potential for use in vehicle shading and personal thermal management. Moreover, its mechanical properties allow for the flexibility needed to meet the demands of everyday use. Our work provides a straightforward and scalable method to manufacture products with exceptional sun shading and radiative cooling capabilities.
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高影响因子
Coatings
·
2023
·Vol. 13
·期 7
·1266
·
IF 3.4
Qian Kou,Weiliang Jin,Chuntao Ge,Jie Pang,Jun Zhang,Geir Martin Haarberg,Saijun Xiao,Ping Wang
In this paper, electrodeposition of a molybdenum coating was conducted in Na3AlF6-NaF-Al2O3-MoO3molten salts at 930 °C to investigate the availability of preparation of thick molybdenum coatings. The effects of current density and electrodeposition time on the morphology of the produced molybdenum coating were studied. With the increase of current density (10~70 mA·cm−2), the coating thickness was increased from 10 μm to 30 μm, with all the current efficiency above 97%. Under a current density of 30 mA/cm2, with the rise of electrodeposition time (10~60 min), three stages of the deposit growth were observed, including the formation of a large number of fine crystals, transformation into fibrous morphology and well-developed faceted grains. The formation of a large number of fine crystals at the initial stage of the electrodeposition could facilitate electroplating molybdenum coatings with good quality at higher current density and longer duration. Thus electrodeposition at a current density of 100 mA·cm−2for 3 h has been performed, resulting in the preparation of relatively flat, dense, and coherent molybdenum coatings with a thickness of 140 μm on a nickel substrate, with a current efficiency above 85%. It is anticipated that the electrodeposition of molybdenum coatings in the present molten system is suitable for electroplating thick molybdenum coatings.Keywords:cryolite-based molten salt;electrodeposition;molybdenum coating;nickel substrate
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Catalysis Science & Technology
·
2023
·Vol. 14
·期 2
·334-342
·
IF 5
Zhou Yang,Ru Wang,Hongji Liu,Zhou Chen,Xiaoli Hu,Limin Sun,Weikun Lai,Yunyun Dong,Weiping Fang,Xiaodong Yi
Selective hydrogenation is a significantly important catalytic process in many industrial processes, where Pd-based catalysts are the most commonly used. Herein, the surface properties of γ-Al2O3 were modified by the layered flower-like architectures of alkaline MgO using a simple hydrothermal method. Then, a series of Pd/Al2O3–MgO catalysts were prepared by an incipient wetness impregnation method for the selective hydrogenation of isoprene. The results showed that the Pd/Al2O3–0.12MgO catalyst exhibited superior catalytic performance with a high activity (93%) and high selectivity (99%) for the semi-hydrogenation products. Systematic studies have demonstrated that the support effect plays an important role in dispersing and stabilizing palladium particles. The reasons for the improved catalytic performance were attributed to the high dispersion of Pd nanoparticles, the changed electronic structure of Pd, and the strong interaction between Pd nanoparticles and supports. This work opens a simple route to regulate the electronic properties of active metal sites via support modification for selective hydrogenation reactions.
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高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Yanzhao Gao,Xianglei Meng,Shiqi Huang,Hui Wu,Liantao Jiang,Yu Zhou,Yuting Song,Yanyan Diao
Gamma alumina is widely utilized for preparing the supported noble metal catalysts for the hydrogenation reaction. It is an effective strategy to improve the catalytic performance of catalysts via modifying gamma alumina with alkaline earth metal to regulate its surface acidity and electronic properties. Herein, Pd catalysts supported by Al 2 O 3 and Mg-modified Al 2 O 3 are synthesized via the wet impregnation method, and the effects of MgO doping on the structure, composition, and surface acidity of Pd/γ-Al 2 O 3 catalysts are investigated via X-ray diffraction patterns (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (TPD). The results show that Pd/MgO-Al 2 O 3 –2 (γ-Al 2 O 3 modified with 2 wt% Mg) has more metallic state palladium and weak acid sites and exhibits the best catalytic performance for the hydrogenation of perfluoro-4-methyl-2-pentene (D1). Density functional theory (DFT) calculations on Pd/Al 2 O 3 and Pd/MgO-Al 2 O 3 –2 catalysts are also performed to further explore the mechanism of D1 hydrogenation. The studies for Gibbs free energy of the potential reaction steps and intermediates reveal a complex process to generate the target product C 6 F 12 H 2 , and the rate-determining-step is the addition of the first hydrogen on the second carbon of perfluoro-4-methyl-2-pentene molecule.
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Chuang-Tian Zhan,Jin-Yuan Wu,Kun-Heng Huang,Yun Li,Li-Xiang Wu,Sheng-Jin He,Yang-Qing Liu,Ze-Xi Zhang,Wei-Ming Guo,Jia-Xiang Xue,Hua-Tay Lin
The pressureless-sintered silicon carbide ceramic with and without surface texturing was joined with CaO-Al 2 O 3 -MgO-TiO 2 -SiO 2 glass filler. The experimental results showed that without texturing applied to SiC substrates, the shear strength of SiC joints was 40.8 ± 6.3 MPa, with failure occurring at the interlayer. Unfilled regions in the interlayer limited the shear strength of the joints. When texturing was applied to SiC substrates, SiO 2 layer was formed on the surface of substrates due to high-temperature oxidation, which subsequently promoted the wettability of filler on substrates. The textured grooves on SiC substrates could be filled with glass material during joining process. The shear strength of textured SiC joints was 69.3 ± 9.9 MPa with a mixed-mode failure when the direction of shear load was perpendicular to the texturing direction. The better wettability, larger joining area, and interlocking structure between the glass filler and substrates enhanced the shear strength of textured joints.
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高影响因子
Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Hanjing Zhu,Meng Zhou,Ke Jing,Baohong Tian,Yi Zhang,Xu Li,Yunzhang Li,Xianhua Zheng,Heng Li,Zipeng Ma,Yong Liu,Alex A. Volinsky,Jin Zou
The 0.5Y 2 O 3 /Al 2 O 3 -Cu/30Mo3SiC and 0.3GO-0.5Y 2 O 3 /Al 2 O 3 -Cu/30Mo3SiC composites were fabricated by fast hot press sintering. Hot compression tests of the composites were carried out using the Gleeble-1500 simulator at 0.001–10 s −1 strain rates and 650–950 °C deformation temperatures. The effects of doped reduced graphene oxide (rGO) on the hot deformation behavior and microstructure of 0.5Y 2 O 3 /Al 2 O 3 -Cu/30Mo3SiC composites were investigated. Trace of molybdenum carbide (MoC) layers/nanoparticles formed in-situ at the rGO-Cu/Mo interface, which is beneficial to the interfacial bonding of the composite. The enhanced flow stress and activation energy of hot deformation is attributed to the addition of the rGO. The activation energy of the composites was improved by 11% with the addition of rGO. The dislocation density and texture orientation ratio decrease at higher deformation temperatures.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 28
·期 32
·43815-43830
·
IF 4.223
Liu Yaxin,Ma Yongwen,Wan Jinquan,Wang Yan,Sun Jian,Xue Yangyang
In this work, Co-Ce-Zr/γ-Al 2 O3 3 particle electrodes were prepared for the efficient degradation of ciprofloxacin (CIP). Co-Ce-Zr/γ-Al 2 O 3 particle electrodes were analyzed with a scanning electron microscope (SEM), X-Ray Diffraction (XRD), X-Ray Fluorescence Spectrometer (XRF), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). According to the results, significant amounts of Co 3 O 4 , CeO 2 , and ZrO 2 were formed on the Co-Ce-Zr/γ-Al 2 O 3 particle electrodes. It was shown that when the conditions of the reaction system were at pH=6, conductivity of 4 ms/cm, current of 0.2 A, initial pollutant concentration of 100 mg/L, and material dosage of 15 g, CIP could be completely degraded within 40 min, and the energy consumed in the reaction was 41.3 kWh/kg CIP. The rate of total organic carbon (TOC) removal by Co-Ce-Zr/γ-Al 2 O 3 particle electrodes was recorded to be approximately 52.6%. Using a response surface methodology, we explored the optimal operating conditions. At the same time, we also explored the influence of inorganic anions in water and actual water medium on the rate of CIP removal. In addition, the ESR data proved that the main active substance in the reaction system was ·OH. The degradation intermediates were investigated, and the possible mechanism was proposed. Thus, this research provided a new solution for the treatment of antibiotic-containing wastewater.
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PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Pengfei Wang,Qing Xia,Yuncheng Zhou,Xueqian Ji,Hailan Feng,Yuxing Xu,Jun Yang,Qiangqiang Tan
The nickel-rich cathode materials (LiNi 0.8 Co 0.15 Al 0.05 O 2 , NCAs) in Lithium ion batteries often suffer from oxygen loss problems under partially overcharged conditions (>4.3 V), leading to capacity fading and safety problem. Herein, we utilize a facile ball-milling method to coat the NCAs with a shell of cerium aluminum composite oxide (CeO 2 -Al 2 O 3 ), which is commonly used as oxygen storage material. Proved by in situ X-ray diffraction results, the coating CeO 2 -Al 2 O 3 layer is capable to suppress the lattice volume change and irreversible phase transition of NCAs. The CeO 2 -Al 2 O 3 coating layer can adsorb released oxygen under overcharged conditions and replenish lattice oxygen of NCAs under oxygen-leaned conditions. The protective layer can also prevent dissolution of the transition metals caused by HF attack in electrolytes. As a result, the as prepared electrode presents high specific capacity of 186.4 mA h g −1 and excellent cycle stability with capacity retention of 94.1% after 300 cycles at a rate of 0.5 C under overcharged conditions (3.0–4.5 V). Coating CeO 2 -Al 2 O 3 is an efficient strategy to solve capacity fading problem and safety problem caused by partially overcharge, and such strategy shows significant promise for practical applications.
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