Catalysts
·
2018
·Vol. 8
·期 8
·296
·
IF 3.465
Shuqi Fang,Kang Bi,Qiao Zhang,Lingpeng Chen,Yongming Sun,Hongyu Huang,Longlong Ma,Chenguang Wang
Layered double hydroxide (LDH) is a layered solid containing positively charged layers with negatively charged anions as an interchangeable interlayer. In this research, Mg(Al)O supports were synthesized with three different Mg:Al molar ratios, and bimetallic PtSn catalysts were loaded onto the supports via the anion exchange method. The properties of ethane dehydrogenation of the PtSn/Mg(Al)O catalysts were investigated. The results show that the structure and properties of the PtSn/Mg(Al)O catalysts were influenced by the Mg:Al molar ratio of the hydrotalcites, which consequently influenced the ethane dehydrogenation performance. When the Mg:Al ratio was 5:1, the ethane dehydrogenation performance was optimal, relative to the Mg:Al ratios of 2:1 and 10:1.Keywords:hydrotalcite;Mg:Al molar ratio;anion exchange method;ethane dehydrogenation
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CARBON
·
2018
·
IF 7.082
Baisong Guo,Biao Chen,Xinming Zhang,Xi Cen,Xinhua Wang,Min Song,Song Ni,Jianhong Yi,Tao Shen,Yong Du
In this work, the effects of aluminum carbide (Al 4 C 3 ) on the mechanical properties and thermal behaviors of Al based composites reinforced by SiC and carbon nanotubes (CNTs) were investigated. The formation of Al 4 C 3 was precisely controlled in the temperature range from 530 °C to 630 °C (80%–95% of the Al melting point) during the post heat treatment. Microscopy observations revealed that Al 4 C 3 rods are originated from CNTs instead of SiC particles. Quantity and size of Al 4 C 3 are highly dependent on the heat treatment temperature. It was found that the mechanical properties of the Al based composites were significantly affected by the size of Al 4 C 3 . Moreover, the formation of Al 4 C 3 helps to decrease the coefficient of thermal expansion (CTE) of the composites due to the consumption of Al and the enhanced interfacial bonding . This study provides a potential approach for ameliorating the mechanical and thermal performances of CNTs reinforced metal matrix composites .
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Energy Technology
·
2018
·Vol. 7
·期 3
·1800747
·
IF 3.175
Pengjing Chen,Longang Tao,Jian Zhu,Guofeng Zhao,Ye Liu,Yong Lu
Indium oxide is as a promising catalyst for the hydrogenation of CO 2 to methanol. Previous studies mainly focused on the cubic-phase In 2 O 3 (C-In 2 O 3 ), but the hexagonal-phase In 2 O 3 (H-In 2 O 3 ) with a corundum structure has been rarely studied because of the difficulty in its synthesis. Herein, the morphology-controllable H-In 2 O 3 in situ structured onto a thin-felt Al 2 O 3 /Al-fiber is prepared by a facile mixed solvothermal method. The amount of H-In 2 O 3 is strongly dependent on the urea/In molar ratio during the mixed solvothermal synthesis. The optimal catalyst obtained at a urea/In ratio of 4.5 possesses the highest amounts of oxygen vacancy and strong basic site. Such catalyst achieves a turnover frequency of 47.8 h −1 (the number of CO 2 converted into methanol per oxygen vacancy site per hour) and is stable for at least 200 h, being capable of converting 4.4% CO 2 into methanol at a selectivity of 67.6% at 325 °C (or higher selectivity at the expense of conversion below 325 °C) with a methanol space time yield of 0.20 g MeOH g cat −1 h −1 . In contrast, the microfibrous-structured C-In 2 O 3 (prepared by the incipient wetness impregnation method) delivers a very low methanol selectivity of only 36.8% under identical reaction conditions. In situ Fourier transform infrared spectroscopy experiments reveal that the H-In 2 O 3 /Al 2 O 3 /Al-fiber catalyzes CO 2 -to-methanol conversion through formate intermediates.
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BIOSENSORS & BIOELECTRONICS
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2012
·
IF 5.602
Kun Shang,Jianying Zhu,Xiaomeng Meng,Ziqiang Cheng,Shiyun Ai
A novel electrochemical immunosensor for ultrasensitive detection of subgroup J of avian leukosis virus (ALVs-J) was designed by using graphene sheets (GS)-layered double hydroxides (LDHs) composites modified electrode with multifunctional Fe 3 O 4 core/Ni–Al LDHs shell (LDHs@Fe 3 O 4 ) nanospheres as labels. At first, the GS-LDHs were used for the immunosensor platform for improving the electronic transmission rate as well as increasing the surface area to capture a large amount of primary antibodies (Ab 1 ). After that, ferrocene (Fc), secondary antibodies (Ab 2 ) and horseradish peroxidase (HRP) multifunctional LDHs@Fe 3 O 4 nanospheres were used as labels with high load amount and good biological activity. Subsequently, in presence of H 2 O 2 , amplified signals were obtained by an electrochemical sandwich immunoassay protocol. To embody the signal amplification property of the protocol, the analytical properties of various immunosensor platform and labels were compared in detail. Under optimal conditions, the reduction peak currents of the electrochemical immunosensor were proportional to the ALVs-J concentration over the range from 10 2.32 to 10 5.50 TCID 50 /mL with a low detection limit (180 TCID 50 /mL, S/N=3). The resulting immunosensor also displayed a good selectivity, reproducibility and stability.
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Catalysts
·
2015
·Vol. 5
·期 4
·1636-1648
·
IF 2
Rui Wang,Xiaolin Xie,Yanxiu Liu,Zhigang Liu,Guofang Xie,Ning Ji,Lizhi Ma,Mingquan Tang
The kiwifruit industry is booming worldwide. As a result, a great deal of kiwifruit waste residue (KWR) containing monosaccharides is produced and discarded. This material shows great potential for the production of platform chemicals. In this study, a series of Nb/Al oxide catalysts were synthesized via a facile and low-cost coprecipitation method, and their structures were characterized using: thermal gravimetric analysis (TGA), XRD, FESEM, TEM, X-ray photoelectron spectroscopy (XPS), NH3-TPD, N2adsorption-desorption, and FTIR-Pyridine adsorption. Experimental results of sugar-to-levulinic acid (LA) conversion revealed that the 20%Nb/Al oxide catalyst provided the highest catalytic performance and durability in terms of LA yield from fructose (74.2%) at 463 K after 10 min and from glucose (47.5%) at 473 K after 15 min. Notably, the 20% Nb/Al oxide catalyst with a 10% dosage is capable of converting kiwifruit waste residue to LA at 473 K after 10 min. In conclusion, the enhanced catalytic performance was obtained due to the high acidity, and large surface areaof Nb/Al oxide catalyst.Keywords:levulinic acid;kiwifruit waste residue (KWR);heterogeneous catalysis;Nb/Al oxide catalyst
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MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
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2016
·
IF 2.647
Chuandong Wu,Kaka Ma,Jialu Wu,Pan Fang,Guoqiang Luo,Fei Chen,Qiang Shen,Lianmeng Zhang,Julie M. Schoenung,Enrique J. Lavernia
We report on an investigation of the influence of reinforcement particle size on the microstructure and mechanical behavior of Al metal matrix composites . In our work, Al 7075/B 4 C composites containing three types of B 4 C particle sizes (56.9 µm, 4.2 µm and 2.0 µm) were synthesized and studied. For a constant value of volume fraction of B 4 C, the composite with coarse reinforcement particles exhibited a relatively homogeneous and discrete distribution of the B 4 C particles while the composites with fine reinforcement exhibited agglomeration of the B 4 C particles. The composite with the smallest B 4 C particles possessed the highest yield strength and fracture strength. Quantitative analysis of the strengthening mechanisms revealed that smaller B 4 C particles lead to larger values in strain gradient strengthening as well as CTE mismatch strengthening, which are significantly correlated to the geometrically necessary dislocations caused by the presence of B 4 C. In addition, the different spatial distributions of the B 4 C particles contributed to different fracture mechanisms in the composites.
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CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Bo Yang,Jianping Deng,Liyan Wei,Yanni Han,Gang Yu,Shubo Deng,Caizhen Zhu,Huabo Duan,Qiongfang Zhuo
2,2′,4,4′-Tetrabromodiphenyl ether (BDE47) is known as a recalcitrant bromated organic pollutant with the significant persistence, toxicity, and bioaccumulation. In this study, a synergistic effect of ball-milled Al particles with vitamin B 12 on the degradation of BDE47 was found according to the coordinated catalytic reduction process. The micro-scale Al particles prepared by ball milling and vitamin B 12 as common pharmaceutical composed a new combination reagent for hydrodebromination with low-cost and high reactivity. The degradation conditions were optimized by the addition of 2.0 g/L BM Al particles and 0.3 mM VB 12 using the solvent of methanol/H 2 O (v:v = 40:60) at pH 4.0. More than 97% of 25 mg/L BDE47 was debrominated into lower-brominated diphenyl ethers in a sequential pattern and finally into diphenyl ethers within a 120-min reaction. UV/Visible spectra showed that vitamin B 12 (Co(III)) was reduced to vitamin B 12s (Co(II)) by the ball-milled Al particles, which possesses super nucleophilic property to associate the carbon atom on C Br bond and then facilitates the hydrodebromination process of brominated diphenyl ethers. The experimental results can provide basic understanding to identify a reaction process of vitamin B 12 /vitamin B 12s for the enhanced reductive debromination of polybrominated diphenyl ethers by ball-milled Al particles, which would be possibly applied to treat soil washing solvent in the field of soil remediation.
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WEAR
·
2015
·
IF 1.913
Z.C. Lu,M.Q. Zeng,Y. Gao,J.Q. Xing,M. Zhu
In this work, an attempt was made to further promote the wear and friction behavior of dual-scale structured Al–12 wt% Sn bearing alloys by coupling with a nano-Si@Sn composite. A so-called tri-modal Al–Sn–Si (denoted as CG-30 Si-containing alloy), which exhibited increased bulk hardness and improved distribution and refinement of the Sn phase, was produced by combining mechanical alloying and conventional powder sintering. The wear performance of the Si-containing and Si-free alloys was differentiated by performing both block-on-ring and ball-on-disk testing. Moreover, the addition of nano-Si@Sn composites to the dual-scale Al–Sn matrix resulted in significant reductions of the friction coefficient and wear volume. These improvements in wear behavior stemmed from the polishing effect of fine Si particles on the counterface , and Sn-rich clusters that acted as lubricants on the worn surface; together, the polishing effect and lubrication led to the formation of a smooth tribolayer, and hence, a decrease in the tendency for abrasive wear . Abrasive wear was also reduced by an increase in the alloy hardness with the addition of Si. As such, Sn-phase modification via Si addition constitutes a promising method for preparing self-lubricating Al-based alloys.
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Journal of Materials Chemistry B
·
2013
·Vol. 1
·期 17
·2268-2274
·
IF 0
Lijian Chen,Bing Sun,Xindong Wang,Fengmin Qiao,Shiyun Ai
In this report, a novel approach for exfoliation of Co–Al layered double hydroxides (LDHs) in aqueous solution of L-asparagine was proposed. L-Asparagine is a water-soluble amino acid whose carbonyl groups would have a strong interaction with the LDH host layers and the amino groups might weaken the interlayer interactions. This simple method did not need reflux at high temperature, overcame the drawback of using organic solvents, and even resulted in a stably stored colloidal suspension of 2D nanosheets. Besides, the peroxidase-like activity of the exfoliated Co–Al LDH (Co–Al ELDH) was enhanced compared with unexfoliated LDH. Co–Al ELDH could rapidly catalyze oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue color reaction. On this basis, simple, rapid and selective colorimetric methods for H2O2 and glucose detection were developed. The presented means was used for glucose detection in fruit juices and fine results were obtained.
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PubMed
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 409
·期 22
·5239-5247
·
IF 3.431
Xie Lijun,Liu Shuqin,Han Zhubing,Jiang Ruifen,Zhu Fang,Xu Weiqin,Su Chengyong,Ouyang Gangfeng
The fiber coating is the key part of the solid-phase microextraction (SPME) technique, and it determines the sensitivity, selectivity, and repeatability of the analytical method. In this work, amine (NH 2 )-functionalized material of Institute Lavoisier (MIL)-53(Al) nanoparticles were successfully synthesized, characterized, and applied as the SPME fiber coating for efficient sample pretreatment owing to their unique structures and excellent adsorption properties. Under optimized conditions, the NH 2 -MIL-53(Al)-coated fiber showed good precision, low limits of detection (LODs) [0.025–0.83 ng L -1 for synthetic musks (SMs) and 0.051–0.97 ng L -1 for organochlorine pesticides (OCPs)], and good linearity. Experimental results showed that the NH 2 -MIL-53(Al) SPME coating was solvent resistant and thermostable. In addition, the extraction efficiencies of the NH 2 -MIL-53(Al) coating for SMs and OCPs were higher than those of commercially available SPME fiber coatings such as polydimethylsiloxane, polydimethylsiloxane–divinylbenzene, and polyacrylate. The reasons may be that the analytes are adsorbed on NH 2 -MIL-53(Al) primarily through π – π interactions, electron donor–electron acceptor interactions, and hydrogen bonds between the analytes and organic linkers of the material. Direct immersion (DI) SPME–gas chromatography–mass spectrometry methods based on NH 2 -MIL-53(Al) were successfully applied for the analysis of tap and river water samples. The recoveries were 80.3–115% for SMs and 77.4–117% for OCPs. These results indicate that the NH 2 -MIL-53(Al) coating may be a promising alternative to SPME coatings for the enrichment of SMs and OCPs.
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Journal of Cleaner Production
·
2024
·
IF 9.7
Xin Li,Xifan Li,Guijing Chen,Di Zhang,Lun Tian,Jun Chen,Changhui Liu,Bo Li,Alberto Tiraferri,Baicang Liu
To minimize manganese loss during acid leaching and to enhance the lithium adsorption capacity from shale gas wastewater of H 1.33 Mn 1.67 O 4 , this adsorbent material was doped with metallic elements in this study. Doping was achieved using solid-phase synthesis, resulting first in a Li 1.33 R X Mn 1.67−X O 4 (R = Fe, Ni, Al) precursor powder through high-temperature calcination. Then, lithium was leached out under acidic environment to obtain the desired H 1.33 R X Mn 1.67−X O 4 (HMO-R) adsorbents. The equilibrium adsorption capacities of HMO-R powders were measured as 20.7 mg/g, 20.7 mg/g, and 29.0 mg/g, for Fe, Ni, and Al dopants, respectively, surpassing that of the former H 1.33 Mn 1.67 O 4 (13.7 mg/L). Moreover, an average reduction of manganese loss by 30% for HMO-R was observed during lithium recovery/extraction cycles by acid leaching compared to undoped Li 1.33 Mn 1.67 O 4 . Overall, the doped adsorbent exhibited a stable crystal structure and high adsorption capacity, enhanced stability, performance, and efficiency in cycling experiments with respect to the undoped material.
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JOURNAL OF CATALYSIS
·
2025
·
IF 6.5
Ping He,Huawei Geng,Lin Li,Qisong Yi,Lu Lin,Zhifeng Liu,Yuanshuai Liu,Valentin Valtchev
Solid acidic Al-MCM-41 materials are characterized by a high specific surface area and well-ordered hexagonally shaped mesopores. However, their relatively weak acidity compared to microporous zeolites significantly limits their practical applications in industrial catalytic reactions, particularly in upgrading biomass-derived organic feedstock that involves reactions with bulky molecules. Herein, we report a novel synthesis route for preparing acidity-enhanced Al-MCM-41 through the phase transformation of MWW-type zeolite precursors. The phase transformation approach markedly facilitates the incorporation of aluminum species into the MCM-41 framework, leading to strong Brønsted acidity of the resultant Al-MCM-41-T samples, as evidenced by comprehensive characterizations including 29 Si and 27 Al MAS NMR, NH 3 -TPD, and Py-IR. Owing to the enhanced acidity and its large pore structures, the as-prepared Al-MCM-41-T-15 sample (with Si/Al = 15) exhibited superior activity and selectivity toward C-alkylated products in both liquid-phase phenol-cyclohexanol and 4-cyclohexylphenol (4-CHP)-cyclohexene alkylation reactions compared the commercial Al-MCM-41-C with a similar Si/Al ratio. These findings afford an effective approach for preparing acidity-enhanced mesoporous solid acids, which hold significant potential for catalyzing lignin-derived bio-oils.
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