RARE METALS
·
2024
·Vol. 44
·期 1
·503-514
·
IF 9.6
Wu Peng,Wang Jun,Li Jian-Yu,Feng Jing,He Wen-Ting,Guo Hong-Bo
In this work, a novel microwave absorbing material (MAM) made of a pseudo-binary of Sr 2 TiMoO 6 –Al 2 O 3 (STM) is proposed first. The MAMs labeled as STM X ( X = 60, 70, 80 and 100, respectively), in which X is the initial weight percent of Sr 2 TiMoO 6 , were synthesized using the solid-state reaction method. Compared with STM100, some equilibrium phases, including SrTiO 3 , Mo, Sr 8 (Al 12 O 24 )(MoO 4 ) 2 and a few undefined ones, are presented in the composites as evidenced by X-ray diffraction results and scanning electron microscopy due to the chemical reaction between Sr 2 TiMoO 6 and Al 2 O 3 component. Besides conductance loss, heterogeneous interfaces between various equilibrium phases introduce interfacial polarization, which causes an enhancement of dissipation for the incident electromagnetic wave. Among the synthesized samples, STM80 presents the best microwave absorbing properties. It has a minimum reflection loss (RL min ) of − 26 dB and an effective absorbing bandwidth up to 2.7 GHz when the thickness is only 1 mm. This indicates that STM80 is a new type of microwave absorbing material with strong absorption and ultrathin thickness.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Yingying Lai,Lizhang Lv,Heqing Fu
In this work, Al 2 O 3 @PPy@rGO composites were successfully synthesized by a “coating-coating” route. The structure of Al 2 O 3 @PPy@rGO composites was characterized by XRD , Raman and SEM. The coaxial wire method was used to measure the electromagnetic properties of Al 2 O 3 @PPy@rGO composites, which was carried on the vector network analyzer (VNA, 3672A/B/C-S) over the 2–18 GHz frequency range. Compared with Al 2 O 3 (about 50 nm), the particle size of Al 2 O 3 @PPy composites (about 70 nm) enhanced, which verified the alumina was coated by PPy . In addition, the Al 2 O 3 @PPy composites are tightly attached by the rGO with a diameter of about 30 nm Al 2 O 3 @PPy@rGO composites have excellent thermal stability, and they remain 53 wt% when the temperature is up to 800 °C. When the thickness of Al 2 O 3 @PPy@rGO composites is 3.0 mm, they reach the maximum reflection loss of −39.7 dB at 13.2 GHz with 15 wt% Al 2 O 3 @PPy@rGO-wax. And the broad effective microwave absorption bandwidth of Al 2 O 3 @PPy@rGO composites is 5.5 GHz in 10.5–16.0 GHz. In addition, the electromagnetic wave absorption mechanism of Al 2 O 3 @PPy@rGO composites was analyzed.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Nano
·
2022
·
IF 13.364
H. Wang,Y. Liu,H. Wang,J. Song,D. Ma,Z. Dai
Efficient utilization of hydrocarbon fuels holds great significance for the current vehicle low-emission requirements and future carbon-neutral society. However, the scenario that limits the effective fuel use and combustion is the present undesirable hydrocarbon-cracking catalysts of low activity, serious coking, and easy degradation. To tackle these issues, we rationally designed and synthesized an active, anti-coking, and recyclable all-in-one zeolite@Ru–Al 2 O 3 catalyst on FeCrAl support by steam-assisted crystallization and atomic layer deposition . Ru nanoclusters dispersedly on ZSM-5 can boost the catalytic efficiency for hydrocarbon cracking and anti-coking, while the protective Al 2 O 3 thin layers further ensure the reusable economy. As for n-dodecane (C 12 H 26 ) cracking reaction, the ZSM-5@Ru–Al 2 O 3 showed a high unit activity up to 0.1253%·ml·mg −1 ·min −1 , low-carbon deposition rate, and the enhanced first-cycle carbon removal rate of 78.3% for recyclable use. Density functional theory (DFT) calculations have further confirmed that high catalytic efficiency and low-carbon deposition benefit from the timely adsorption of C 12 H 26 and timely transfer of reactant products at the composite interface. This work opens interesting possibilities for the rational design and fabrication of high-efficient, anti-coking, and recyclable hydrocarbon cracking catalysts through multifunctional structural regulations.
研究领域:
催化化学
·
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of CO2 Utilization
·
2024
·
IF 7.2
Luqman Abdullahi Sani,Haolong Bai,Zifu Xu,Liangliang Fu,Yining Sun,Xiaorui Huang,He Gao,Xuejing Liu,Dingrong Bai,Zhanguo Zhang,Fabing Su,Jiao Liu,Guangwen Xu
Ni/Al 2 O 3 catalysts (noted as Ni/Al-350, Ni/Al-500, and Ni/Al-700, respectively) were synthesized by a facile solution combustion method but at different combustion temperatures (350 °C, 500 °C, and 700 °C, respectively). For comparison, Ni/Al 2 O 3 (noted as Ni/Al-100) was also prepared by the impregnation method and applied in the methanation reaction. The Ni/Al 2 O 3 synthesized at the combustion temperature of 350 °C showed better performance than the others at higher combustion temperatures, and the activity for CO 2 methanation followed an order of Ni/Al-350 > Ni/Al-500 > Ni/Al-700 > Ni/Al-100. The increase in the combustion temperature decreased active sites for the H 2 and CO 2 adsorption, which could be associated with the reduced Ni dispersion and basic sites, thus lowering its activity and increasing its carbon deposition rate.
研究领域:
催化化学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 13
·2959
·
IF 4.2
Hejingying Niu,Jinhua Ma,Lina Gan,Kezhi Li
In this study, a PtSn/Al2O3catalyst with bimetallic uniform distribution in the sphere was synthesized. The PDH performance and characterization analyses, such as with FTIR, XPS, and NH3-TPD, were investigated. The effects of acid on the PDH performance were analyzed. Citric acid (CA) acted as a competing adsorbent in the preparation process of the PtSn/Al2O3catalyst to synthesize the uniform catalyst. Water washing and alkali-treated samples were also studied. SEM line scanning revealed that increased the apparent concentration of Pt metal from 0.23 to 0.30 with citric acid. In contrast to the fresh PtSn/Al2O3catalyst, the addition of citric acid increased the PDH selectivity from 74% to 93%. After alkali or water washing treatments, the catalyst’s selectivity further increased to 96%. Strong acid sites promoted the breaking of C–C bonds during the PDH reaction, resulting in more methane and ethylene byproducts, and decreased catalyst selectivity for fresh PtSn/Al2O3. From the PDH reaction thermodynamic analysis, a relatively sub-atmospheric pressure environment with a lower propane pressure could be the reasonable choice.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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.
研究领域:
环境科学
·
电化学
·
废水处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2019
·Vol. 34
·期 5
·1003-1007
·
IF 0.605
Wu Yicheng,He Yannan,Yu Zhiqiang
The effect of interfacial modification on flexural strength of epoxy composites filled with modified ZrB 2 -Al 2 O 3 composite fillers was investigated in order to explore the stress distribution of modified composites under external load. The mechanical performance of epoxy composites filled with 0 vol%, 1 vol%, 3 vol% and 5 vol% unmodified and modified ZrB 2 -Al 2 O 3 fillers was characterized by three point bending (TPB) tests. The fracture surfaces of epoxy composites were observed by scanning electronic microscope (SEM). The results showed that the epoxy composite reinforced by 1 vol% modified fillers exhibited the optimal mechanical performance. According to the Von Mises stress contours simulated by finite element models (FEM) and the SEM images, it was shown that the modified ZrB 2 -Al 2 O 3 multiphase fillers could homogenize the stress in the epoxy composites due to the transition effect resulted from the interfacial modification layers on the surfaces of multiphase fillers. It contributed to the improvement of mechanical performance of epoxy composites further.
研究领域:
材料科学
·
力学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Shifeng Huang,Feng Gao,Qinggang Li,Xin Cheng
Samples with various ratios of AlN/Al 2 O 3 were fabricated via vacuum hot-pressing at 1700 °C under an applied pressure of 30 MPa for 90 min using Y 2 O 3 as a sintering aid. The densification process, microstructural development, and formation of AlON phase from Al 2 O 3 and AlN were investigated. Al 2 O 3 additive can improve the physical and mechanical properties , and purification of the grain boundaries. AlON are almost formed completely when the content of Al 2 O 3 is 80 vol%. The effects of composition, microstructure, and exposure time at 1400 °C on the oxidation behavior of AlN samples with different amounts of Al 2 O 3 were investigated. The sample with 80 vol% alumina has the best oxidation resistance .
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
CATALYSIS COMMUNICATIONS
·
2019
·
IF 3.674
Cuncun Zuo,Yun Tian,Yanxia Zheng,Lei Wang,Zhongjun Fu,Tiantian Jiao,Ming Wang,Haofei Huang,Yuchao Li
Series of gold and ceria supported γ-Al 2 O 3 catalysts were developed for the oxidative esterification of methacrolein with methanol. All the catalysts were prepared through one step deposition-precipitation method, and K 2 CO 3 and urea were used as precipitant, respectively. Au, CeO 2 and γ-Al 2 O 3 could self-assemble unique particle morphology during co-precipitation process and form semi-core shell or core shell structure after calcination . The relationship between catalytic reactivity and structural characteristics were analyzed by SEM, TEM, EDS, BET, XRD, XPS, etc. Among Au-CeO 2 /γ-Al 2 O 3 (K 2 CO 3 ), Au-Ce/γ-Al 2 O 3 (Urea) and Au/γ-Al 2 O 3 (Urea) catalysts with different active components and precipitant, the last two exhibited higher catalytic activity. Moreover, the Ce-doped catalysts shown higher stability than just Au supported on pure alumina. The active stability of the optimum Au-Ce/γ-Al 2 O 3 catalyst was evaluated with seven-time cyclic reactions exhibiting high stability and activity with the yield of MMA above 90%.
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
POLYMER COMPOSITES
·
2023
·Vol. 44
·期 6
·3221-3231
·
IF 5.2
Zijian Lu,Wei Wu,Dietmar Drummer,Yi Wang,Chao Liu,Shuo Li,Xintong Zhao
It is of great significance to study new thermal conductivity filler in practical thermal management application. In this study, a multi-scale assembled thermal conductivity composite Al 2 O 3 -ZnO NWs/GO/EP was developed. The test results showed that the composite has good thermal conductivity and mechanical properties with low filler content. When the GO content is 1.5 wt% and the Al 2 O 3 -ZnO NWs content is 25 wt%, the thermal conductivity of the composites reaches 2.15 W/mK, which is improved by about 1032% compared with the pure epoxy resin, and the tensile strength of the composites is maintained at a high level. The problems of high filling capacity and poor mechanical properties of alumina filler were effectively solved. It provides a new idea for preparing the filled thermal conductivity composites with low filling capacity and high thermal conductivity.
研究领域:
材料科学
·
热管理应用
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Han-Bing Gao,Le-Le Qiu,Fa-Peng Wu,Jian Xiao,Yun-Peng Zhao,Jing Liang,Yong-Hui Bai,Fang-Jing Liu,Jing-Pei Cao
Catalytic hydrogenolysis of C O bonds in lignin provides a promising route to produce high value-added biofuels and chemicals. However, designing highly active and stable catalysts for this process is still a challenge. Herein, a series of Ni/Al 2 O 3 catalysts were synthesized by calcination and reduction of layered double hydroxide precursors, and their activities were evaluated in the catalytic conversion of lignin-derived compounds. Diphenyl ether was completely converted with a 100% monomeric selectivity (cyclohexane and cyclohexanol) over the optimized Ni/Al 2 O 3 -500 under the optimal conditions of 200 ℃, 0.5 MPa H 2 and 1.5 h, indicating the excellent catalytic activity in the cleavage of C O bonds of the catalyst. The excellent catalytic performances of Ni/Al 2 O 3 -500 were originated from its relatively large specific surface area, well-developed porosity, small crystallite size, high Ni 0 concentration and strong interaction between the active metal and support. The reusability experiments show that Ni/Al 2 O 3 -500 possesses a relatively high stability for six reuses. Moreover, various lignin model compounds can be completely converted to corresponding monomeric products over Ni/Al 2 O 3 -500, indicating the applicability of this ingenious catalyst. The application of the hydrotalcite-derived Ni-based catalysts with high activity and stability provides a promising approach for the efficient hydrogenolysis of lignin derivatives.
研究领域:
催化化学
·
生物质转化
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2023
·Vol. 29
·期 18
·e202203152
·
IF 4.3
Yan Long,Jie He,Hang Zhang,Yingkang Chen,Kang Liu,Junwei Fu,Hongmei Li,Li Zhu,Zhang Lin,Andrei Stefancu,Emiliano Cortes,Mingshan Zhu,Min Liu
Graphical Ag/Al 2 O 3 catalytic controllable synthesis of N-monomethylated amines by using CO 2 /H 2 as C 1 source has been demonstrated in a first example. The reactivity of methylated amines was reduced by the heterolytic dissociation of H 2 over the catalyst, and hence conversion of various amines to corresponding monomethylated amines was enabled with excellent selectivity. The selective synthesis of monomethylated amines with CO 2 is particularly challenging because the formation of tertiary amines is thermodynamically more favorable. Herein, a new strategy for the controllable synthesis of N-monomethylated amines from primary amines and CO 2 /H 2 is explored. First-principle calculations reveal that the dissociation of H 2 via an heterolytic route reduces the reactivity of methylated amines and thus inhibit successive methylation. In situ DRIFTS proves the process of formation and decomposition of ammonium salt by secondary amine reversible binding with H + on the Ag/Al 2 O 3 catalyst, thereby reducing its reactivity. Meanwhile, the energy barrier for the rate-determining step of monomethylation was much lower than that of overmethylation (0.34 eV vs. 0.58 eV) means amines monomethylation in preference to successive methylation. Under optimal reaction conditions, a variety of amines were converted to the corresponding monomethylated amines in good to excellent yields, and more than 90 % yield of product was obtained.
研究领域:
催化化学
·
绿色化学
·
材料科学
✓ 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）