MATERIALS CHEMISTRY AND PHYSICS
·
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.
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高影响因子
FOOD CHEMISTRY
·
2021
·
IF 7.514
Shuyun Bi,Di Shao,Yue Yuan,Rui Zhao,Xu Li
A novel surface-enhanced Raman spectroscopy (SERS) method for the determination of nitrofurazone was developed using AuNPs/ γ -Al 2 O 3 nanoparticles protected by β -cyclodextrin ( β -CD) as substrate prepared in our lab. The optimum experimental conditions were obtained from single factor procedure and response surface modeling. A linear relationship ( I SERS = 508.96 c + 31987.87, c : nmol L −1 , R 2 = 0.996) between SERS intensity and the concentration of nitrofurazone in the range of 3.3 – 667.0 nmol L −1 was established, the limit of detection (LOD) was found at nmol L −1 level (0.37 nmol L −1 by 3 S 0 / S ). The selectivity for the method was studied by the influences of foreign substances on the determination. The recoveries and RSD (n = 5) for the six meat samples were 95.1 % – 104.5% and 2.4 % – 4.8% respectively, which suggesting that the new SERS method was successfully to detecting nitrofurazone.
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PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Bin Han,Shigen Zhu,Weiwei Dong,Yunfeng Bai,Hao Ding,Yilan Luo,Ping Di
(85-x)WC–15 wt%Al 2 O 3 –xTiC (x = 0, 1.5, 2.5, 5, 10, and 20 wt%) composites were prepared by vacuum hot-press sintering. The influence of TiC addition on the corrosion behaviour of WC–Al 2 O 3 composites in 0.1 M NaOH solution was revealed. The results suggest that all the samples containing added TiC had the TiC phase and (W, Ti) C solid-solution phase, while the base composite had neither phase. With increasing added TiC content, the average grain size of WC decreased, and the relative density first increased and then decreased. Furthermore, the results suggest that the addition of TiC could noticeably increase the free corrosion potential and impedance and reduce the corrosion current density. However, the composite containing 20 wt% added TiC showed the opposite trend. Therefore, it can be concluded that the corrosion performance of the composites in an alkaline medium can be improved by adding an appropriate amount of TiC. The change in corrosion properties was caused by changes in the solid-solution phase, relative density, and TiO 2 oxide film .
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JOM
·
2021
·Vol. 73
·期 11
·3451-3459
·
IF 2.474
Chen Ben,Li Zhi-Bo,Zhang Guo-Hua,Chou Kuo-Chih
To improve the performance of Mo-based cermets, Mo-(Ni)-Al 2 O 3 cermets were prepared with raw materials of nano-sized Al 2 O 3 powder. The effects of Al 2 O 3 and Ni additions on the densification behavior, microstructure, bending strength, and hardness of the Mo-(Ni)-Al 2 O 3 cermets were experimentally analyzed. The results showed the content of Al 2 O 3 had a great influence on the degree of densification of Mo-Al 2 O 3 cermets at the sintering temperature of 1600°C. In addition, the Al 2 O 3 particles were distributed evenly in the matrix of Mo-based cermets, which refined the grains of Mo and increased the hardness of cermets. Because of the weak interfacial bonding strength between Al 2 O 3 ceramic phase and Mo metal phase, the bending strength decreased continuously with increasing Al 2 O 3 content. However, Ni addition improved the wetting and adhesion of Al 2 O 3 and Mo. With the addition of Ni, the relative density increased, and thus hardness and bending strength were improved.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Chunxiang Wan,Yuzhen Pan,Zhen Chen,Jinglu Hu,Zhe Zhang,Yawen Sun,Wei Ma
The application of Zinc oxide has drawn great attention in bacterial inhibition and contaminant degradation field in recent years. The internal structure and the morphology of the material was characterized by XRD , XPS , SEM , TEM. The dopant of 1 wt% graphene oxide（GO） and 30 wt% Al 2 O 3 shows excellent piezocatalytic and antibacterial ability. Application potential of the material is investigated by the degradation of RhB and the inhibition of Bacillus. It is found that the RhB solution can be degraded 92.5% by ZA-GO in 15 min, while ZnO can degrade 64.2%. It shows superior catalytic behavior in successive experiments of degradation of RhB without obvious decrease in efficiency. The quenching experiment combined with ESR spectrum demonstrate that both •O 2 - and •OH radicals were generated, while •OH did the most damage. Bacterial inhibition tests have also proven that the generation of reactive oxygen species cause the bacteria inactivated. In this work, a novel composite ZnO-Al 2 O 3 /GO has been successfully prepared based on mechanical synthesis method. Graphene oxide has higher mechanical strength and higher specific surface area. Zn ions doping carbon materials not only increases its stability, but also promotes its conductivity. The doping of Al atoms effectively reduce the work function of ZnO. Graphene oxide together with alumina coordinate the band gap of piezoelectric materials ZnO and the catalytic reaction efficiency was dramatically enhanced. What’s more, this work provides a facile approach eliminated the use of solvents and organic reagents, ensuring greater environmental safety. The novel zinc oxide matrix composites are depicted as a promising candidate to be used as intelligent antibacterial agent and alleviate environmental pollution.
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ENERGY CONVERSION AND MANAGEMENT
·
2019
·
IF 7.181
Yujiao Zhang,Shengli Niu,Chunmei Lu,Zhiqiang Gong,Xun Hu
This research focused on the novel, low-cost and green NaAlO 2 /γ-Al 2 O 3 heterogeneous nanocatalyst, which exhibited the excellent performance in catalyzing transesterification of palm oil with methanol for the biodiesel production. The physicochemical properties of the catalysts were characterized by different methods of the X-ray diffraction (XRD), N 2 adsorption–desorption, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), Hammett indicators, field emission scanning electron microscopy-energy dispersive spectrometer (FESEM-EDS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). The transesterification parameters, such as the methanol to oil molar ratio, catalyst content and reaction temperature, were optimized using the central composite design (CCD) based the response surface methodology (RSM), where the maximum biodiesel yield of 97.65% was achieved at the methanol to oil molar ratio of 20.79:1, catalyst content of 10.89 wt% and reaction temperature of 64.72 °C. The biodiesel yield was dropped to 52.16% for the third reused cycle due to the leaching of the active sites into the liquid phase. However, the spent catalyst could be effectively regenerated with a small number of active sites and the regenerated catalyst maintained the biodiesel yield of 93.29% for the sixth reused cycle. The properties of the produced biodiesel were in accordance with the ASTM D 6751 standard. Also, the biodiesel production process was environmental friendly based on the green chemistry metrics.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Guolin Cao,Zhuomin Jin,Jie Zhu,Yunjiao Li,Bin Xu,Yike Xiong,Jiachao Yang
Poor cycling and rate performance are considered one of the greatest obstacles to the large-scale commercialisation of Ni-rich layered cathode material , especially at high cut-off voltages. In this study, we successfully prepared amorphous Al 2 O 3 -coated LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) cathode material by the straightforward carboxymethyl cellulose (CMC)-assisted wet chemical method . As the cathode material for lithium-ion batteries, the amorphous Al 2 O 3 -coated NCM523 maintains capacity retention of 86.30% in the range of 3.0–4.6 V after 100 cycles at 1C and 86.57% at 8C after 50 cycles, which is higher than that of pristine NCM523 under the same conditions (76.40% and 63.20%, respectively). The uniform Al 2 O 3 coating layer greatly inhibits transition metal dissolution on the surface of NCM523 cathode materials at high cut-off voltage. In addition, the structural damage of the NCM523 cathode is effectively retarded due to the consumption of HF by Al 2 O 3 . This work will provide inspiration for the design of new methods for the commercialisation of Ni-rich layered cathode material.
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Catalysts
·
2019
·Vol. 9
·期 10
·849
·
IF 3.444
Zeyu Xue,Zhaoping Zhong,Bo Zhang,Chao Xu
To investigate the catalytic pyrolysis performance of complex metal oxide catalysts for biomass, γ-Al2O3was prepared through the precipitation method, and then ZrO2and γ-Al2O3were blended in the proportion of 2:8 using the co-precipitation method. Next, CeO2was loaded on the surface of the catalyst for further modification. The three catalysts, A, ZA and CZA, were obtained. The specific surface and acidity of the catalysts were characterized by nitrogen adsorption–desorption and NH3-Temperature Programmed Desorption (NH3-TPD) respectively. The catalytic pyrolysis performance of catalysts for bamboo residues was investigated by Pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Chromatograms were analyzed for identification of the pyrolysis products and the relative amounts of each component were calculated. Experimental results indicated that catalyst A had a good catalytic activity for the fast pyrolysis of bamboo residues. The addition of ZrO2and CeO2could continuously enhance the acidity of the catalyst and further promote the pyrolysis of macromolecular compounds and deoxidation of oxygen-containing compounds. Finally, catalyst CZA, obtained by compound modification, could not only dramatically reduce the relative content of phenol, acid and aldehyde and other oxygen-containing compounds, but also achieved the maximum hydrocarbon yield of 23.38%. The catalytic performance of catalyst CZA improved significantly compared with catalyst A.Keywords:biomass;pyrolysis;catalytic cracking;Py-GC/MS;complex metal oxides
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ChemistrySelect
·
2019
·Vol. 4
·期 43
·12479-12490
·
IF 1.716
Guoming Zhao,Enyuan Gao,Qiaoqiao Wan,Qing Liu,Junjie Liang,Yingyun Qiao,Guangzhen Zhao,Yuanyu Tian
Graphical The efficient aerobic oxidative esterification reaction of 1,3-propanediol and methanol to form methyl 3-hydroxypropionate in the presence of 1.5 wt. % Au/Al 2 O 3 catalysts prepared using the deposition-precipitation or colloid-deposition method were investigated. Preparation methods and calcination temperature of catalyst played important role in improving the catalytic activity in this work. 1.5 wt. % Au/Al 2 O 3 catalysts were prepared using the deposition-precipitation or colloid-deposition method and calcined at different temperatures for the selective oxidative esterification reaction of 1,3-propanediol and methanol to form methyl 3-hydroxypropionate (3-HPM). The catalysts were characterized by nitrogen adsorption, transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy, X-ray photoelectron spectra (XPS), CO 2 temperature-programmed desorption (CO 2 -TPD) and NH 3 temperature-programmed desorption (NH 3 -TPD). The effect of the calcination temperature of the catalyst prepared by the deposition-precipitation method on the catalytic performance for the selective oxidative esterification of 1,3-propanediol was studied. The results showed that the conversion of 1,3-propanediol and the selectivity of 3-HPM increased at first and then decreased with the increase of the calcination temperature of catalyst. The highest conversion of 1,3-propanediol and selectivity of 3-HPM at the optimal calcination temperature of 350 °C were 92.0% and 88.5%, respectively. Considering the effects of preparation method and calcination temperature, it could be concluded that the metallic Au nanoparticles with appropriate particle size in coordination with the suitable amount of weak and middle acid and base sites, were favorable to the oxidative esterification of 1,3-propanediol and methanol to 3-HPM. Moreover, we found that the 1.5 wt. % Au/Al 2 O 3 catalyst could be effectively recovered without obvious decline of the catalytic properties.
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RSC Advances
·
2019
·Vol. 9
·期 19
·10702-10714
·
IF 3.049
Cunlong Li,Yuqing Zhang,Ming Yong,Wei Liu,Jiaqi Wang
In order to effectively clean oily seawater with anionic polyacrylamide (APAM), UiO-66 coated γ-Al2O3 (UA) composites were firstly synthesized using γ-Al2O3 as a template to induce the growth of high hydrophilic UiO-66 on its surface to form a uniform UA self-assembled membrane. The UA composites and self-assembled membrane were characterized and analyzed. Also, the membrane performance was investigated. The results show that the hydrophilicity of particles is enhanced with the water contact angle decreasing from 39.8° (γ-Al2O3 particles) to 26.2° (UA composites) by introducing the UiO-66 coating. Moreover, the UA self-assembled membrane performs attractive water yield and separation performance. The oil concentration in the permeate treated by the first class of UA self-assembled membrane declines apparently from 91.22 to 18.90 mg L−1, while the water yield is as high as 657.89 L m−2 h−1. The reclaimed separation experiments show that the membrane materials could be recycled by calcination at 200 °C and hydraulic cleaning, which gives the material potential application in cleaning oily seawater.
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PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 35
·13891-13898
·
IF 3.069
Fenfen Lu,Daohua Sun,Xia Jiang
In this dissertation, silver–palladium (AgPd) bimetallic nanoparticles were synthesized by a green biosynthesis method using Cacumen platycladi leaf extract, which provided both reductive and protective agents. Then the supported AgPd/γ-Al2O3 catalysts were obtained by the sol-immobilization method, and the as-biosynthesized AgPd/γ-Al2O3 catalysts with different particle sizes and compositions were used for 1,3-butadiene hydrogenation. Optimization of the catalyst preparation and selective hydrogenation parameters was performed. Using the catalyst, a 1,3-butadiene conversion of 98.2% and a butene selectivity of 88.1% were achieved. The durability experiment of AgPd/γ-Al2O3 catalysts was carried out for 50 h, and the activity decreased slightly and the selectivity almost remains the same during the 50 h, indicating their remarkable stability. The results of TEM and TG analysis showed that the size of the AgPd nanoparticles was nearly the same before and after the durability experiment, and the existence of residual biomolecules on the catalyst surface helped to prevent agglomeration and modification of the surface properties of the catalyst, which would promote desorption of the product, and then avoid intensifying the level of further hydrogenation.
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CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Lini Zhu,Sifan Zeng,Zhen Teng,Heng Luo,Xiaochun Han,Chen Chen,Wanlin Feng,Yongqiang Tan,Haibin Zhang
Macroscopic parallel aligned non-woven carbon fibers were incorporated into Al 2 O 3 composites in this study to evaluate the contribution of multiple reflections to the total electric magnetic interference (EMI) shielding. Results indicate that parallel aligned non-woven carbon fiber layers contribute significantly to the total EMI shielding effectiveness (SE T ) of Al 2 O 3 composites by largely enhancing the EMI absorption, and seven parallel aligned thin non-woven carbon fiber layers finally make the almost microwave-transparent Al 2 O 3 an excellent EMI shielding material with an EMI SE T as high as 29–32 dB in the X-band frequency range. The volume fraction of carbon fibers in Al 2 O 3 composites with seven carbon fiber layers is calculated to be only 0.5%, and therefore the EMI SE enhancement efficiency by parallel aligned large non-woven carbon fiber layers is much higher than other highly conducting nano fillers. It validates the significance of multiple reflections in achieving high EMI shielding properties in ceramic composites and provides an instructive approach to design efficient EMI shielding ceramic composites.
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