Journal of Materials Chemistry A
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2016
·Vol. 4
·期 29
·11357-11364
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IF 8.262
Teng Liu,Pingping Zhao,Xing Hua,Wei Luo,Shengli Chen,Gongzhen Cheng
A simple Zn/Fe bimetallic zeolitic–imidazolite framework (ZIF) carbonization method is developed to synthesize an Fe–N–C hybrid with hierarchical nitrogen-doped porous carbons crossed by carbon nanotubes. Both the specific ratios of Zn/Fe in the bimetallic metal–organic framework (MOF) precursors and the selected annealing temperature are essential for the formation of this unique hybrid structure with good conductivity and exposure of more active sites. The resulting FeNC-20-1000 hybrid electrocatalyst exhibits excellent oxygen reduction reaction (ORR) activity, with a half-wave potential of 0.770 V comparable to that of the commercial Pt/C catalysts in acidic media, and a half-wave potential of 0.880 V, ca. 50 mV more positive than that of Pt/C for ORR in alkaline solution. More importantly, the as-prepared Fe–N–C hybrid exhibits much more stability for the ORR in both acidic and alkaline solutions than Pt/C, which makes it among the best non-noble-metal catalysts ever reported for ORR under acidic and alkaline conditions.
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Polymers
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2016
·Vol. 8
·期 11
·389
·
IF 2.944
Lihua Guo,Xinyu Jing,Shuoyan Xiong,Wenjing Liu,Yanlan Liu,Zhe Liu,Changle Chen
A series of alkyl- and aryl-substituted iminopyridine Fe(II) complexes1a–7aand Co(II) complexes2b,3b,5b, and6bwere synthesized. The activator effect, influence of temperature, and, particularly, the alkyl and aryl substituents’ effect on catalytic activity, polymer molecular weight, and regio-/stereoselectivity were investigated when these complexes were applied in isoprene polymerization. All of the Fe(II) complexes afforded polyisoprene with high molecular weight and moderatecis-1,4 selectivity. In contrast, the Co(II) complexes produced polymers with low molecular weight and relatively highcis-1,4 selectivity. In the iminopyridine Fe(II) system, the alkyl and aryl substituents’ effect exhibits significant variation on the isoprene polymerization. In the iminopyridine Co(II) system, there is little influence observed on isoprene polymerization by alkyl and aryl substituents.Keywords:iminopyridine;Iron(II);Cobalt(II);isoprene polymerization;selectivity
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2017
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IF 3.012
Shuo Duan,Yuming Huang
A novel electrochemical sensor was developed for the sensitive and selective detection of Cu 2 + , Pb 2 + and Cd 2 + , which was based on NH 2 -MIL-88(Fe)-rGO composite modified glass carbon electrode (NH 2 -MIL-88(Fe)-rGO/GCE). The NH 2 -MIL-88(Fe)-rGO composite was facilely prepared by a one-step method and characterized by SEM, XRD, Raman spectrum and electrochemical methods. The stepwise GCE modified process was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of Cu 2 + , Pb 2 + and Cd 2 + ions on the NH 2 -MIL-88(Fe)-rGO/GCE were explored by differential pulse anodic stripping voltammetry (DPASV). It was found that NH 2 -MIL-88(Fe)-rGO was capable of adsorbing Cu 2 + , Pb 2 + and Cd 2 + ions from aqueous solutions and the NH 2 -MIL-88(Fe)-rGO/GCE could enhance the electrochemical responses of Cu 2 + , Pb 2 + and Cd 2 + effectively. Important operational parameters such as electrolyte pH and deposition time were investigated and optimized for the determination of trace Cu 2 + , Pb 2 + and Cd 2 + ions. Under the optimum conditions, the proposed electrochemical sensor had a linear range of 0.005––0.3 μM for Cd 2 + , 0.01–0.3 μM for Pb 2 + and 0.005–0.05 μM for Cu 2 + , respectively. The limits of detection (LODs) are 4.9 nM for Cd 2 + , 10 nM for Pb 2 + and 3.6 nM for Cu 2 + , respectively. The proposed method has been successfully applied to determine three metal ions in water samples. The developed sensor promises simple preparation, fast operation, good sensitivity and excellent reusability, showing great potential for monitoring of water quality.
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JOURNAL OF SOLID STATE CHEMISTRY
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2017
·
IF 2.299
Zhen Ge,Xin Li,Wenguo Zhang,Qili Sun,Chunpeng Chai,Yunjun Luo
In this paper, the ultrafine Fe-O compound/ammonium perchlorate (AP) nanocomposites were prepared via in-suit growth method. The structure and morphology of the nanocomposites were characterized by infrared spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion X-ray spectrometer (EDS) and transmission electron microscopy (TEM) test. The results showed that the prepared Fe-O compound nanoparticles were amorphous state and deduced as 2L-ferrihydrite. The size of Fe-O compound/AP nanocomposites could be effectively controlled by changing the recrystallization condition. 2L-ferrihydrite nanoparticles was evenly dispersed in the nanocomposites proved by EDS and TEM analysis. Furthermore, the thermal decomposition of Fe-O compound/AP nanocomposites was analysized by TG-DSC method. The prepared 2L-ferrihydrite nanoparticles of the nanocomposites showed good catalytic effect on AP because of their decreasing the decomposition temperature and increasing the total heat release of AP.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2017
·
IF 6.198
Gui-Xiang Huang,Chu-Ya Wang,Chuan-Wang Yang,Pu-Can Guo,Han-Qing Yu
A high-efficient, low-cost, and eco-friendly catalyst is highly desired to activate peroxides for environmental remediation. Due to the potential synergistic effect between bimetallic oxides’ two different metal cations, these oxides exhibit superior performance in the catalytic activation of peroxymonosulfate (PMS). In this work, novel Mn1.8Fe1.2O4 nanospheres were synthesized and used to activate PMS for the degradation of bisphenol A (BPA), a typical refractory pollutant. The catalytic performance of the Mn1.8Fe1.2O4 nanospheres was substantially greater than that of the Mn/Fe monometallic oxides and remained efficient in a wide pH range from 4 to 10. More importantly, a synergistic effect between solid-state Mn and Fe was identified in control experiments with Mn3O4 and Fe3O4. Mn was inferred to be the primary active site in the surface of the Mn1.8Fe1.2O4 nanospheres, while Fe(III) was found to play a key role in the synergism with Mn by acting as the main adsorption site for the reaction substrates. Both sulfate and hydroxyl radicals were generated in the PMS activation process. The intermediates of BPA degradation were identified and the degradation pathways were proposed. This work is expected to help to elucidate the rational design and efficient synthesis of bimetallic materials for PMS activation.
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ULTRASONICS SONOCHEMISTRY
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2012
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IF 3.567
Deming Zhao,Min Li,Dexing Zhang,Shams Ali Baig,Xinhua Xu
Palladium/Iron (Pd/Fe) nanoparticles were prepared by using ultrasound strengthened liquid phase reductive method to enhance dispersion and avoid agglomeration. The dechlorination of 2,4-dichlorophenol (2,4-DCP) by Pd/Fe nanoparticles was investigated to understand its feasibility for an in situ remediation of contaminated groundwater. Results showed that 2,4-DCP was first adsorbed by Pd/Fe nanoparticles, then quickly reduced to o-chlorophenol (o-CP), p-chlorophenol (p-CP), and finally to phenol (P). The induction of ultrasound during the preparation of Pd/Fe nanoparticles further enhanced the removal efficiency of 2,4-DCP, as a result, the phenol production rates increased from 65% (in the absence of ultrasonic irradiation) to 91% (in the presence of ultrasonic irradiation) within 2 h. Our data suggested that the dechlorination rate was dependent on various factors including Pd loading percentage over Fe 0 , Pd/Fe nanoparticles availability, temperature, mechanical stirring speed, and initial pH values. Up to 99.2% of 2,4-DCP was removed after 300 min reaction with these conditions: Pd loading percentage over Fe 0 0.3 wt.%, initial 2,4-DCP concentration 20 mg L −1 , Pd/Fe dosage 3 g L −1 , initial pH value 3.0, and reaction temperature 25 °C. The degradation of 2,4-DCP followed pseudo-first-order kinetics reaction and the apparent pseudo-first-order kinetics constant was 0.0468 min −1 .
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SENSORS AND ACTUATORS B-CHEMICAL
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2015
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IF 4.097
He Mei,Wenqin Wu,Beibei Yu,Huimin Wu,Shengfu Wang,Qinghua Xia
Fe@Pt core–shell nanoparticles were synthetized by spontaneous replacement reaction, using Vulcan XC-72 carbon as support. The physical properties of the obtained Fe@Pt/C nanocomposites were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, and the electrocatalytic performances of the Fe@Pt/C were evaluated by cyclic voltammetry and chronoamperometry . Compared with the Pt/C, the Fe@Pt/C exhibited preferable electrocatalytic activity towards the reduction of hydrogen peroxide, and the oxidation of glucose and formaldehyde. Amperometric sensing of hydrogen peroxide was linear to its concentration in the range from 2.5 μM to 41.605 mM, with a detection limit of 750 nM (S/N = 3) and a sensitivity of 218.97 μA mM −1 cm −2 . At the same time, the sensor based on Fe@Pt/C showed a linear response range of 1–16 mM glucose, and of 12.5 μM–15.4 mM formaldehyde, with high sensitivities of 11.75 μA mM −1 cm −2 and 40.18 μA mM −1 cm −2 , respectively.
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CHINESE JOURNAL OF CATALYSIS
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2014
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IF 1.552
Guoqiang Song,Zhiqing Wang,Liang Wang,Guoru Li,Minjian Huang,Fengxiang Yin
Effective bifunctional catalysts play a vital role in large-scale commercial applications of rechargeable lithium-air batteries. In this article, a metal-organic framework, MOF(Fe), was prepared by a hydrothermal process using ferric nitrate as the metal ion precursor and trimesic acid as an organic ligand. The structure of the MOF(Fe) was characterized by X-ray diffraction, N 2 adsorption-desorption, Transmission electron microscopy, Fourier transform infrared spectroscopy and Thermo-gravimetric analysis. The activity for the oxygen reduction reaction (ORR) and the kinetic behavior of the ORR using the MOF(Fe) were investigated by cyclic voltammetry and rotating disk electrode voltammetry, respectively, using an alkaline electrolyte. The characterization results showed that the MOF(Fe) was highly crystalline with abundant micropores, large specific surface area and high thermal stability. The MOF(Fe) exhibited excellent catalytic activity for the ORR. The ORR mechanism varies with the applied potentials. The ORR occurs through a two-electron pathway at potentials in the range of −0.30 to −0.50 V, but shifts to four-electron pathway with the potentials in the range −0.50 to −0.95 V. In addition, the MOF(Fe) shows excellent catalytic activity for the oxygen evolution reaction (OER) in an alkaline electrolyte. This work opens a new route for the development of effective non-precious metal catalysts based on MOFs for the ORR and OER.
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ULTRASONICS SONOCHEMISTRY
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2014
·
IF 3.816
Deming Zhao,Yiya Zheng,Min Li,Shams Ali Baig,Donglei Wu,Xinhua Xu
In this study, nickle/iron (Ni/Fe) nanoparticles were synthesized by liquid phase reductive method in the presence of 20 kHz ultrasonic irradiation to improve nanoparticles’ disparity and avoid agglomeration. The characterized results showed that this method has obviously modified most of the particles in term of sizes and specific surface areas. Meanwhile, the improved nanoscale Ni/Fe particles were employed for the reductive dechlorination of 2,4-dichlorophenol (2,4-DCP) as a function of some influential factors (Ni content, Ni/Fe nanoparticles dosage, reaction temperature and initial pH values) and degradation path. Experimental results showed that 2,4-DCP was first adsorbed by Ni/Fe nanoparticles, then quickly reduced to o -chlorophenol ( o -CP), p -chlorophenol ( p -CP), and finally to phenol (P). The application of ultrasonic irradiation for Ni/Fe nanoparticles synthesis was found to significantly enhance the removal efficiency of 2,4-DCP. Consequently, the phenol production rates increased from 68% (in the absence of ultrasonic irradiation) to 87% (in the presence of ultrasonic irradiation) within 180 min. Nearly 96% of 2,4-DCP was removed after 300 min reaction with these optimized conditions: Ni content over Fe 0 3 wt%, initial 2,4-DCP concentration 20 mg L −1 , Ni/Fe dosage 3 g L −1 , initial pH value 3.0, and reaction temperature 25 °C. The degradation of 2,4-DCP followed pseudo-first-order kinetics reaction and the apparent pseudo-first-order kinetics constant was 0.0737 min −1 . This study suggested that the presence of ultrasonic irradiation in the synthesis of nanoscale Ni/Fe particles could be a promising technique to enhance nanoparticle’s disparity and avoid agglomeration.
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DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 41
·18227-18236
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IF 4.197
Ruowen Liang,Rui Chen,Fenfen Jing,Na Qin,Ling Wu
H3PMo12O40 molecules have been successfully encapsulated in the cavities of MIL-100(Fe) via a facile hydrothermal method (denoted as HPMo@MIL-100(Fe)). A series of characterization has corroborated the insertion of H3PMo12O40 within the cavities of MIL-100(Fe). The resulting HPMo@MIL-100(Fe) nanocomposites have exhibited much higher photoactivity than the original-MIL-100(Fe) toward the photocatalytic selective oxidation of benzylic alcohols and the reduction of Cr(VI) under visible light irradiation (λ ≥ 420 nm). The higher photoactivity of HPMo@MIL-100(Fe) can be attributed to the integrative effect of enhanced light absorption intensity and more efficient separation of photogenerated electron–hole pairs. The host porous structure of MIL-100(Fe) can achieve a uniform composition with H3PMo12O40, which is significantly important for producing highly reactive dispersed H3PMo12O40 molecules and enhancing the photocatalytic activity of HPMo@MIL-100(Fe) nanocomposites. And the immobilized H3PMo12O40 molecules are more convenient for recycling. Importantly, almost no Fe and Mo ions leach from the MIL-100(Fe) during the reaction, which verifies the photostability of the HPMo@MIL-100(Fe). In addition, possible photocatalytic redox reaction mechanisms have been investigated.
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Nano Energy
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2017
·
IF 12.343
Wenjun Fan,Zelong Li,Chenghang You,Xu Zong,Xinlong Tian,Shu Miao,Ting Shu,Can Li,Shijun Liao
In this work, CuCl 2 as a promoter was added into the mixture of polythiophene (PTh), FeCl 3 , and melamine for preparing Fe-Cu-N/C catalyst. The catalyst features one-dimensional bamboo-like carbon nanotubes with few metal oxide nanoparticles encapsulated into tubes. The catalyst exhibits excellent activity toward the oxygen reduction reaction (ORR) with half-wave potential 50 mV more positive than the commercial Pt/C in 0.1 M KOH. It also shows comparable ORR activity in 0.1 M HClO 4 solution. Moreover, it exhibits superior long-term stability and excellent methanol tolerance in both alkaline and acidic solutions. The outstanding catalytic performance of Fe-Cu-N/C catalyst can be ascribed to the doping of Cu in the Fe-N-C architecture, which promotes the formation of bamboo-like nanotube structure and the generation of interaction among Cu and Fe-N-C. This synthetic strategy may open new avenues for constructing highly efficient electrocatalysts that adding of an inactive metal can obviously promote the catalytic performance of catalysts.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2017
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IF 3.133
Yan Cheng,Yong Li,Guangbin Ji,Bin Quan,Xiaohui Liang,Zixin Zhao,Jieming Cao,Youwei Du
In this study, an extremely simple one-step ball milling has been applied to fabricate the flaky Fe 3 O 4 /Fe composites. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and vector network analysis (VNA). It is acknowledged that the ball-milling process has huge influence on the morphology and electromagnetic absorption capability. Compared with the raw Fe 3 O 4 , the saturation magnetization of Fe 3 O 4 /Fe composites improved greatly. When the thickness is just 1.25 mm, the reflection loss values below −10 dB can be achieved from 13.8 to 18 GHz, with a maximum reflection loss of −25.9 at 16.1 GHz. Obviously, the Fe 3 O 4 /Fe composites can be used as magnetic microwave absorbers due to its simple synthesis for the mass production standards. Moreover, this study also gives new enlightenment to design other magnetism/magnetism composites that can be applied to Ku-band such as satellite communications.
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