CATALYSIS TODAY
·
2014
·
IF 3.309
Cong Zhang,Jing Xing,Liang Song,Hongchuan Xin,Sen Lin,Lishu Xing,Xuebing Li
Aqueous phase catalytic upgrading of phenolic monomers to hydrocarbons have been explored using Pd/C combined with HZSM-5 zeolite catalysts in the presence of H 2 . 2-Methoxyl-4-allylphenol (eugenol), which consists of methyl ether bond, hydroxyl group, aromatic ring and propyl olefin bond, was chosen as a classic lignin model compound. This research focuses on the relationship between the acidity of zeolites and the deoxygenation activities basis on the hydrodeoxygenation (HDO) of eugenol. The results indicated that the decrease of Si/Al ratio resulted in the increase of the acidity of the zeolites, which significantly influenced their catalytic performance for product distributions. Over the HZSM-5 (Si/Al = 12.5) catalyst, the 2-methoxyl-4-propylphenol conversion of 86.5% and the hydrocarbon selectivity of 73.4% were obtained with the HDO of eugenol under 513 K and 5 MPa hydrogen pressure. Owing to the lower selectivity of hydrocarbon with HZSM-5 (Si/Al = 50) as acidic catalyst, the pore treatment was used to enlarge the outer surface of zeolite. After modified by alkali-treatment, much more acid active sites were provided for feasible accessibility of oxygenated reactants. The selectivity of hydrocarbons was improved by the alkaline treatment of HZSM-5 zeolite with 0.3 mol L −1 sodium hydroxide solution.
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Analytical Methods
·
2015
·Vol. 8
·期 1
·214-221
·
IF 1.821
Ai Gao,Dan Zhang,Xue-Bo Yin
To obtain comprehensive information and to compensate the limits of individual modalities in molecular imaging, the research on dual-modal imaging probes (DMIPs) attracts much interest. Here, we report a reliable and facile procedure to prepare near infrared fluorescence (NIRF)-magnetic resonance (MR) DMIPs using Cy5-labeled, Gd–Al co-doped mesoporous silica nanoparticles (MSNs). Amine-modified, Gd–Al co-doped MSNs were first synthesized through one-step co-condensation. A Cy5-NHS ester was then coupled to the amino groups to produce the DMIPs, which were denoted as Gd–Al@MSNs-Cy5. High intensity NIRF and a relaxation rate (17.7 mM−1 s−1) were observed. Featuring the lower background and the deeper penetration depth, the cutting-edge NIRF imaging was achieved. Moreover, the larger surface area of MSNs could be modified with more NIRF probes, Cy5, for improved NIRF. Following the Solomon–Bloembergen–Morgan theory, enhanced MR performance was illustrated by the relaxation rate because MSNs have a porous structure that enables access of water into the interior, and co-doping with Al in the MSNs promotes the doped amount of Gd. The exchange rate of water is much more accelerated through doping Gd and Al since a disordered pore arrangement is found in Gd–Al co-doped MSNs. The DMIPs in saline were injected into mice through the tail vein for imaging and basic pharmacokinetics studies. They were excreted by the stomach and intestine in 3 h, a circulation time long enough for imaging. Thus, Gd–Al@MSNs-Cy5 are attractive for clinical NIRF-MR dual-modal imaging by integrating the biocompatibility of MSNs, the NIRF of Cy5, and the high MR response of Gd.
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RSC Advances
·
2014
·Vol. 4
·期 64
·34008-34013
·
IF 3.708
Dan Xu,Weili Li,Lidong Wang,Wei Wang,Wei-Dong Fei
BaTiO3 and 1.5 mol% AlN/BaTiO3 (AlN/BT) piezoceramics were prepared via a conventional solid-state reaction method. The effects of sintering temperature on the phase structure, preferential orientation degree of Al3+–N3− pairs and electrical properties of the ceramics were investigated and analyzed. The AlN/BT ceramic sintered at 1325 °C obtains the optimum piezoelectric properties of d33 = 305 pC N−1, kp = 0.33 and Qm = 140 due to the preferential distribution of Al3+–N3− pairs and suitable sintering temperature. The high temperature stability testing reveals that these AlN-doped BT ceramics are useable at temperatures as high as approximately 115 °C. These properties indicate that this system is a potential high piezoelectric lead-free candidate material to be further studied.
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ANALYTICAL CHEMISTRY
·
2013
·
IF 5.695
Cheng-Xiong Yang,Hu-Bo Ren,Xiu-Ping Yan
Fluorescent metal–organic frameworks (MOFs) have received great attention in sensing application. Here, we report the exploration of fluorescent MIL-53(Al) for highly selective and sensitive detection of Fe3+ in aqueous solution. The cation exchange between Fe3+ and the framework metal ion Al3+ in MIL-53(Al) led to the quenching of the fluorescence of MIL-53(Al) due to the transformation of strong-fluorescent MIL-53(Al) to weak-fluorescent MIL-53(Fe), allowing highly selective and sensitive detection of Fe3+ in aqueous solution with a linear range of 3–200 μM and a detection limit of 0.9 μM. No interferences from 0.8 M Na+; 0.35 M K+; 11 mM Cu2+; 10 mM Ni2+; 6 mM Ca2+, Pb2+, and Al3+; 5.5 mM Mn2+; 5 mM Co2+ and Cr3+; 4 mM Hg2+, Cd2+, Zn2+, and Mg2+; 3 mM Fe2+; 0.8 M Cl–; 60 mM NO2– and NO3–; 10 mM HPO42–, H2PO4–, SO32–, SO42–, and HCOO–; 8 mM CO32–, HCO3–, and C2O42–; and 5 mM CH3COO– were found for the detection of 150 μM Fe3+. The possible mechanism for the quenching effect of Fe3+ on the fluorescence of MIL-53(Al) was elucidated by inductively coupled plasma-mass spectrometry, X-ray diffraction spectrometry, and Fourier transform infrared spectrometry. The specific cation exchange behavior between Fe3+ and the framework Al3+ along with the excellent stability of MIL-53(Al) allows highly selective and sensitive detection of Fe3+ in aqueous solution. The developed method was applied to the determination of Fe3+ in human urine samples with the quantitative spike recoveries from 98.2% to 106.2%.
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PubMed
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 21
·5103-5113
·
IF 9.125
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Lu-Fang Ma,Yanliang Yang
The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca–Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
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Catalysis Science & Technology
·
2016
·Vol. 6
·期 14
·5656-5667
·
IF 5.287
Fufeng Cai,Guomin Xiao
In this work, a series of Cu–Co–Al catalysts with different Ce loadings were applied to the hydrogenolysis of glycerol to 1,2-propanediol in a fixed-bed flow reactor. The physicochemical properties of the synthesized catalysts were analyzed using BET, N2O chemisorption, SEM, TEM, XRD, H2-TPR, NH3-TPD and XPS techniques. Systematic characterization demonstrated that the incorporation of Ce into the Cu–Co–Al catalyst could effectively restrain the aggregation of active metal species as well as the growth of metallic particles during calcination and reduction, which resulted in the formation of highly dispersed active metals. Large amounts and superior strength of acid sites were present in the Ce-promoted Cu–Co–Al catalysts, as confirmed by NH3-TPD analysis. The reducible nature of the Cu–Co–Al catalyst greatly increased after the addition of Ce. The higher concentration of acid sites, excellent reducibility and highly dispersed active metals were responsible for the superior catalytic activity of the 8Ce/Cu–Co–Al catalyst and it attained 91.6% glycerol conversion and 92.4% 1,2-propanediol selectivity. In addition, the effects of different process parameters such as the solvent, reaction temperature, operating pressure, catalyst loading, glycerol concentration and liquid flow rate on glycerol hydrogenolysis together with the catalyst stability were studied in detail, showing that the Ce-promoted Cu–Co–Al catalyst had high efficiency and stability for glycerol hydrogenolysis.
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MATERIALS CHEMISTRY AND PHYSICS
·
2017
·
IF 2.084
Yanjun Yin,Xueming Li,Yuanjie Shu,Xiaogang Guo,Hebin Bao,Wulin Li,Yuhua Zhu,Yu Li,Xinyue Huang
A novel porous Al/CuO nanothermite was successfully synthetized by utilizing the controllable electrophoretic deposition (EPD) method. The morphology and phase composition of the CuO and Al/CuO films were investigated in detail by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). When the pH of the solution was 2.0, the surface area of the Al/CuO film was able to reach 495.6 m 2 /g, which was much higher than that of films grown at pH 1.0, 3.0 or 4.0. Meanwhile, the combustion performance and energy outputs were coincident with the results mentioned above. At pH 2.0, bright flames were observed after ignition, and the released heat of the nanothermite reaction reached 3.49 kJ/g, exhibiting excellent combustion performance and enhanced energy output.
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Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 36
·9465-9471
·
IF 5.256
Ting Lu,Hongjie Song,Xiaoqun Dong,Jianyu Hu,Yi Lv
NH2-MIL-53(Al) nanorods studded with F− were successfully synthesized via coordination modulation with HF as a modulator. The investigation of the growth mechanism pointed out that F− plays a key role in the formation process. The incorporation of F− into the framework of NH2-MIL-53(Al) not only made the crystal morphology tunable but also magnified the fluorescence enhancement performance of NH2-MIL-53(Al) in water vapor, based on which a highly efficient humidity sensor was fabricated. Among different kinds of humidity sensors, the present sensing system stood out due to its fast response rate, good sensitivity and high selectivity with a low detection limit of 0.6 μg mL−1 (S/N = 3) and a wide detection range from 4 to 40 μg mL−1. On the other hand, a majority of the conventional electronic humidity sensors seriously suffered from temperature dependence, while the present sensing system got over this disadvantage. Therefore, the NH2-MIL-53(Al) nanorod layer-based fluorescence sensing system has the potential for application in the real-time monitoring of humidity under ambient conditions.
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JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2016
·Vol. 31
·期 6
·1211-1218
·
IF 0.4
Zhang Dan,Zhao Guoqing,Yu Jingang,Yan Tao,Zhu Mingyue,Jiao Feipeng
Adsorption of 2, 4, 6-trichlorophenol (TCP) onto the calcined Mg/Al-CO 3 layered double hydroxide (CLDH) was investigated. The prepared Mg/Al-CO 3 layered double hydroxide (LDH) and CLDH were characterized by powder X-ray diffraction (XRD) and thermo gravimetric analyzer-differential scanning calorimeters (TG-DSC). Moreover, 2,4,6-trichlorophenol (TCP) was removed effectively (94.7% of removal percentage in 9 h) under the optimized experimental conditions. The adsorption kinetics data fitted the pseudo-second-order model well. The Freundlich, Langmuir, and Tempkin adsorption models were applied to the experimental equilibrium adsorption data at different temperatures of solution. The adsorption data fitted the Freundlieh adsorption isotherm with good values of the correlation coefficient. A mechanism of the adsorption process is proposed according to the intraparticle diffusion model, which indicates that the overall rate of adsorption can be described as three steps.
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CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Xin Huang,Man Su,Jizhi Zhou,Weikang Shu,Zhifeng Huang,Naiyun Gao,Guangren Qian
Persulfate based advanced oxidation processes have been well investigated, with the generation of radical species via various activation methods. This study reports an activation pathway of peroxydisulfate (S 2 O 8 2− , PDS) without radical production, achieved by the intercalation of PDS into Mg/Al-layered double hydroxide (LDH). Physical characterization indicated that the LDH was intercalated by PDS with the interlayer distance increasing to 0.917 nm. Approximately 93.9% of the phenol was decomposed by a LDH-PDS composite containing 0.4 mmol/g PDS, whilst no removal of phenol was achieved in the control group with PDS. Moreover, sulfate from decay of PDS was likely kept in the layers of LDH for no sulfate leakage in solution was observed. This is in accordance with the occurrence of characteristic peaks assigned for sulfate in FT-IR spectrum of LDH-PDS after reaction. Interestingly, radicals were not recorded by electron spin resonance measurement or radical scavenger tests during the oxidation process. The reactivity of PDS was likely improved by the basic sites on the LDH laminate, which provided OH to activate the O O bond in PDS. Further, the limited space of LDH layers reduce the bond cleavage of intercalated PDS and thus the generation of radicals. Therefore, the results proposed a non-radical reaction between phenol and PDS in the interlayer of LDH and developed a novel activation pathway for PDS in the elimination of organic contaminants.
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APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Xiang Ke,Xiang Zhou,Gaozi Hao,Lei Xiao,Jie Liu,Wei Jiang
One of the challenges for the application of energetic materials is their energy-retaining capabilities after long-term storage. In this study, we report a facile method to fabricate superhydrophobic Al/Fe 2 O 3 nanothermite film by combining electrophoretic deposition and surface modification technologies. Different concentrations of dispersion solvents and additives are investigated to optimize the deposition parameters. Meanwhile, the dependence of deposition rates on nanoparticle concentrations is also studied. The surface morphology and chemical composition are characterized by field-emission scanning electron microscopy, X-ray diffraction, X-ray energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. A static contact angles as high as 156° shows the superhydrophobicity of the nanothermite film. Natural and accelerated aging tests are performed and the thermal behavior is analyzed. Thermal analysis shows that the surface modification contributes to significantly improved energy-release characteristics for both fresh and aged samples, which is supposed to be attributed to the preignition reaction between Al 2 O 3 shell and FAS-17. Superhydrophobic Al/Fe 2 O 3 nanothermite film exhibits excellent long-time storage stability with 83.4% of energy left in natural aging test and 60.5% in accelerated aging test. This study is instructive to the practical applications of nanothermites, especially in highly humid environment.
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THERMOCHIMICA ACTA
·
2024
·
IF 3.1
Jiaming Liu,Xinwen Ma,Wenhao Wang,Weiduo Fei,Xiandie Zhang,Xiang Ke,Xiang Zhou
In this study, Cu(OH)F nanoparticles are prepared through a simple hydrothermal reaction and their effects on the thermal oxidation and ignition characteristics of micron-sized Al powder (μ-Al) are explored for the first time. Thermal analysis in air atmosphere (50∼1050 °C) shows that compared to raw μ-Al, the normalized weight gain of Al in Al-Cu(OH)F increases by about 36.9%, 64.8%, and 106.3% when the added Cu(OH)F is 1 wt%, 3 wt%, and 5 wt%, respectively. After mixed with NH 4 ClO 4 , electric ignition and open-air combustion tests show shortened ignition delay time (by 42.6%∼63.8%) and increased maximum light intensity (by 48.9%∼117.8%) for Al-Cu(OH)F. The effects of Cu(OH)F result from its decomposition products, namely, HF and CuO. HF reacts with alumina shell to form AlF 3 , which sublimes at high temperature and thus exposes Al core instantly, while CuO can react with Al core to release heat, further facilitating the thermal oxidation and ignition processes.
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