Micro & Nano Letters
·
2019
·Vol. 14
·期 9
·976-979
·
IF 0.975
Wen Zeng,Qiqi Yang,Bin Shao,Donglin Guo,Chunhong Li,Yilong Ma,Xueguo Yin,Sibo Zhao,Kejian Li
The monodisperse Fe@SiO 2 core-shell nanocapsules were synthesised via hydrothermal reaction followed with heat treatment. Nanostructures were characterised by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The magnetic properties of Fe@SiO 2 nanocapsules were evaluated with magnetic property measurement system. The results show that Fe@SiO 2 core-shell nanocapsules are highly monodispersed. The silica thickness of Fe@SiO 2 nanocapsules increased from 10–20 to 25–35 nm with increasing tetraethyl orthosilicate (TEOS) amount. In the Fe@SiO 2 nanocapsules prepared with 900 μl TEOS, as the reaction temperature increases, the mean particle size of Fe@SiO 2 nanocapsules increases from 328 to 546 nm. It is remarkable that the saturation magnetisation of Fe@SiO 2 nanocapsules decreases with increasing silica thickness. However, the coercivity of nanocapsules has less influence with the variation of silica thickness and particles’ length.
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Polymers
·
2018
·Vol. 10
·期 9
·934
·
IF 2.935
Guangqian Zhu,Xianhui Zhang,Mengmeng Zhao,Liang Wang,Chuyang Jing,Peng Wang,Xiaowu Wang,Qinggang Wang
A series of iminopyridine complexes of Fe(II) and Co(II) complexes bearing fluorinated aryl substituents were synthesized for the polymerization of isoprene. The structures of complexes3a,2band3bwere determined by X-ray diffraction analysis. Complex3acontained two iminopyridine ligands coordinated to the iron metal center forming an octahedral geometry, whereas2badopted a chloro-bridged dimer, and3bfeatured with two patterns of cobalt centers bridged via chlorine atoms. Complexes2band3brepresented rare examples of chlorine bridged bimetallic Co(II) complexes. The fluorine substituents effects, particularly on catalytic activity and polymer properties such as molecular weight and regio-/stereo-selectivity were investigated when these complexes were employed for isoprene polymerization. Among the Fe(II)/methylaluminoxane (MAO) systems, the 4-CF3substituted iminopyridine Fe(II) complex1awas found as a highly active isoprene polymerization catalyst exhibiting the highest activity of 106g·(mol of Fe)−1·h−1. The resultant polymer displayed lower molecular weight (Mn= 3.5 × 104g/mol) and moderate polydispersity index (PDI = 2.1). Furthermore, the ratio ofcis-1,4-/3,4 was not affected by the F substituents. In the series of Co(II)/AlEt2Cl binary systems, complexes containing electron-withdrawing N-aryl substituents (R = 4-CF3, 2,6-2F) afforded higher molecular weights polyisoprene than that was obtained by the complex containing electron-donating N-alkyl substituents (R = octyl). However, ternary components system, complex/MAO/[Ph3C][B(C6F5)4] resulted in low molecular weight polyisoprene (Mn< 2000) with hightrans-1,4-unit (>95%).Keywords:iminopyridine ligands;Fe(II);Co(II) complexes;isoprene polymerization;fluorinated aryl substituents
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MATERIALS RESEARCH BULLETIN
·
2014
·
IF 1.968
Li-Ping Jia,Bing Yan
RE–Fe–B–Na (RE = Nd–Er) colloidal nanoparticles are prepared by high-temperature solution synthesis. These nanoparticles are ultra-small monodisperse, air-stable and amorphous, whose particle size and magnetic property are characterized by transmission electron microscope and superconducting quantum interference device. Taking Nd–Fe–B–Na nanoparticle as an example, it is found that the particle size can be controlled in less than 7 nm. Besides, the magnetic properties of RE–Fe–B–Na colloidal nanoparticles can be compared for different rare earth elements. Based on the bulk ferromagnetic coupling, other possible magnetic coupling mechanism is discussed.
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RSC Advances
·
2014
·Vol. 4
·期 88
·47615-47624
·
IF 3.708
Ping Li,Chunbo Liu,Guoling Wu,Yang Heng,Shuang Lin,Ao Ren,Kehan Lv,Lisong Xiao,Weidong Shi
In this paper, Fe-doped SrTiO3 (FSTO) photocatalysts were successfully prepared via a facile solvothermal method, and their photocatalytic activities for degrading tetracycline (TC) under visible light irradiation were examined. It was found that doping Fe3+ into the lattice of SrTiO3 resulted in the formation of new absorption bands in the visible light region, and the energy band gap decreased from 3.2 eV to 2.6 eV with Fe3+ doping amounts of 0 to 5 wt%. The photocatalytic experimental results indicated that the as-prepared FSTO photocatalysts generate an extremely high enhancement in the TC degradation ratio compared to the pure SrTiO3 under visible light irradiation. In particular, the FSTO sample doped with 3% Fe exhibited the highest TC degradation ratio (71.6%) in 80 min, which is mainly attributed to the narrowed gap generated by the appropriate level of Fe3+ doping. This work suggests that this doping method should be applicable for exploiting other efficient visible light-driven photocatalysts with wide band gap semiconductors.
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CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Zhouwei Miao,Xiaogang Gu,Shuguang Lu,Dionysios D. Dionysiou,Souhail R. Al-Abed,Xueke Zang,Xiaoliang Wu,Zhaofu Qiu,Qian Sui,Muhammad Danish
The performance of chelated Fe(II)-based catalyzed sodium percarbonate (SPC) stimulating the degradation of perchloroethylene (PCE) in aqueous solution was investigated using six different chelating agents (CA), namely, citric acid monohydrate (CIT), oxalic acid (OA), l -ascorbic acid (ASC), ethylenediaminetetraacetic acid (EDTA), trisodium citrate 2-hydrate (CIT-Na 3 ), and EDTA-Na 2 , at CA/Fe(II)/SPC/PCE molar ratios of 2/4/4/1, 4/4/4/1 and 8/4/4/1. The results indicated that the addition of CIT and OA significantly enhanced the PCE degradation. In addition, investigations using free radical probe compounds and radical scavengers revealed that PCE was primarily degraded by HO radical oxidation in Fe(II)/SPC, CIT/Fe(II)/SPC, and OA/Fe(II)/SPC systems and O 2 − also participated in the degradation of PCE in CIT/Fe(II)/SPC and OA/Fe(II)/SPC systems. The intensity of HO detected by electron paramagnetic resonance (EPR) in CIT/Fe(II)/SPC and OA/Fe(II)/SPC systems indicated that the addition of CIT or OA indeed enhanced the continuous production of HO and enabled the intensity of HO to be more stable. The results demonstrated that CIT and OA significantly improved the PCE degradation efficiency by increasing the concentration of Fe(II) and maintaining the concentration of HO radicals in solution. In conclusion, chelated Fe(II)-based catalyzed SPC oxidation process shows enormous practical prospects for the remediation of PCE-contaminated groundwater because of the effectiveness without pre-adjusting the solution pH and complete mineralization in Fe(II)/SPC, CIT/Fe(II)/SPC and OA/Fe(II)/SPC systems.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2013
·Vol. 21
·期 2
·1401-1410
·
IF 2.618
Wu Xiaoliang,Lu Shuguang,Qiu Zhaofu,Sui Qian,Lin Kuangfei,Du Xiaoming,Luo Qishi
Most studies on the treatment of chlorinated contaminants by Fe(0) focus on aqueous system tests. However, few is known about the effectiveness of these tests for degrading chlorinated contaminants such as 1,1,1-trichloroethane (TCA) in soil. In this work, the reductive degradation performance of 1,1,1-TCA by Fe(0) was thoroughly investigated in a soil slurry system. The effects of various factors including acid-washed iron, the initial 1,1,1-TCA concentration, Fe(0) dosage, slurry pH, and common constituents in groundwater and soil such as Cl − , HCO 3
− , SO 4
2− , and NO 3
− anions and humic acid (HA) were evaluated. The experimental results showed that 1,1,1-TCA could be effectively degraded in 12 h for an initial Fe(0) dosage of 10 g L −1 and a soil/water mass ratio of 1:5. The soil slurry experiments showed two-stage degradation kinetics: a slow reaction in the first stage and a fast reductive degradation of 1,1,1-TCA in the second stage. The reductive degradation of 1,1,1-TCA was expedited as the mass concentration of Fe(0) increased. In addition, high pHs adversely affected the degradation of 1,1,1-TCA over a pH range of 5.4–8.0 and the reductive degradation efficiency decreased with increasing slurry pH. The initial 1,1,1-TCA concentration and the presence of Cl − and SO 4
2− anions had negligible effects. HCO 3
− anions had a accelerative effect on 1,1,1-TCA removal, and both NO 3
− and HA had inhibitory effects. A Cl − mass balance showed that the amount of Cl − ions released into the soil slurry system during the 1,1,1-TCA degradation increased with increasing reaction time, suggesting that the main degradation mechanism of 1,1,1-TCA by Fe(0) in a soil slurry system was reductive dechlorination with 1,1-DCA as the main intermediate. In conclusion, this study provides a theoretical basis for the practical application of the remediation of contaminated sites containing chlorinated solvent.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2014
·
IF 2.129
Zhengjuan Sun,Yali Liu,Yuanfang Li
A novel and rapid spectrofluorometry method for the recognition of 6-mercaptopurine (6-MP) has been developed based on luminescent metal–organic frameworks Fe-MIL-88NH 2 as fluorescent probe. The strong fluorescence of Fe-MIL-88NH 2 at 430 nm could be quenched by 6-MP directly, and the Fe-MIL-88NH 2 shows high selectivity for 6-MP compared to other thiol-containing amino acids such as homocysteine (Hcy), cysteine (Cys), glutathione (GSH), etc. Under optimal conditions, the relative fluorescence intensity was linearly proportional to the concentration of 6-MP in the range of 5–600 μM with the detection limit at 1.17 μM (S/N = 3). Furthermore, the present approach has been successfully applied to the determination of 6-MP in human serum samples. The possible fluorescence quenching mechanism has also been investigated, where it is revealed that the quenching was attributed to competition of absorption of the light source energy as well as electron transfer between Fe-MIL-88NH 2 and 6-MP.
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Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 34
·18071-18080
·
IF 8.867
Zhigao Zhu,Chenghan Ji,Lingling Zhong,Shuang Liu,Fuyi Cui,Hongliang Sun,Wei Wang
Porous carbonaceous materials are widely used as catalyst carriers to activate peroxymonosulfate (PMS) for catalytic oxidative degradation of organic pollutants. Herein, hierarchical structured ferro-cobalt alloyed crystals supported on nitrogen doped activated porous carbon fibers (FeCo2@APCFs) were prepared by a combination of multicomponent electrospinning, activation, and carbonization. Benefiting from the precursor design and activation process, the carbon fibers derived from a PAN/PBZ (polyacrylonitrile/polybenzoxazine) precursor exhibited a tunable porous structure with an ultrahigh specific surface area (SSA) and pore volume of 2085 m2 g−1 and 1.12 cm3 g−1, respectively. Most importantly, the FeCo2 crystals can be directly synthesized by carbonization at high temperature in a N2 flow with no other reducing gases. The as-prepared FeCo2@APCFs exhibited robust activation of PMS with reactive oxygen radicals (SO4˙−, ˙OH, and 1O2) for ultrafast removal of organic pollutants, as well as good stability and recyclability with high total organic carbon (TOC) removal. The catalyst suspended in aqueous solution after catalysis can be easily separated with an external magnet without tedious separation processes. This study is meaningful for the development of novel catalyst carriers or a fascinating strategy for wastewater treatment.
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Journal of Nanomaterials
·
2016
·
IF 1.758
Yongli Zhang,Shujuan Dai,Yanbo Zhou,Kai Lin
Fe-Co-Ce composite catalysts were prepared by coprecipitation method using CO(NH2)2, NaOH, NH4HCO3, and NH3·H2O as precipitant agents. The effects of the precipitant agents on the physicochemical properties of the Fe-Co-Ce based catalysts were investigated by SEM, TEM, BET, TG-DTA, and XRD. It was found that the precipitant agents remarkably influenced the morphology and particle size of the catalysts and affected the COD removal efficiency, decolorization rate, and pH of methyl orange for catalytic wet air oxidation (CWAO). The specific surface area of the Fe-Co-Ce composite catalysts successively decreased in the order of NH3·H2O, NH4HCO3, NaOH, and CO(NH2)2, which correlated to an increasing particle size that increased for each catalyst. For the CWAO of a methyl orange aqueous solutions, the effects of precipitant agents NH3·H2O and NaOH were superior to those of CO(NH2)2 and NH4HCO3. The catalyst prepared using NH3·H2O as the precipitant agent was mostly composed of Fe2O3, CoO, and CeO2. The COD removal efficiency of methyl orange aqueous solution for NH3·H2O reached 92.9% in the catalytic wet air oxidation. Such a catalytic property was maintained for six runs.
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ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Yingfang Yao,Yong You,Gaixia Zhang,Jianguo Liu,Haoran Sun,Zhigang Zou,Shuhui Sun
Tuna is one of the most rapid and distant swimmers. Its unique gill structure with the porous lamellae promotes fast oxygen exchange that guarantees tuna’s high metabolic and athletic demands. Inspired by this specific structure, we designed and fabricated microporous graphene nanoplatelets (GNPs)-based Fe/N/C electrocatalysts for oxygen reduction reaction (ORR). Careful control of GNP structure leads to the increment of microporosity, which influences the O2 adsorption positively and desorption oppositely, resulting in enhanced O2 diffusion, while experiencing reduced ORR kinetics. Working in the cathode of proton-exchange membrane fuel cells, the GNP catalysts require a compromise between adsorption/desorption for effective O2 exchange, and as a result, appropriate microporosity is needed. In this work, the highest power density, 521 mW·cm–2, at zero back pressure is achieved.
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CARBON
·
2017
·
IF 6.337
Jingyan Liu,Yang Liu,Peng Li,Luhai Wang,Haoran Zhang,Hui Liu,Jialiang Liu,Yixian Wang,Wei Tian,Xiaobo Wang,Zhongtao Li,Mingbo Wu
Fe-N-doped porous carbon derived from petroleum asphalt (NPCA) was prepared via a facile template synthesis method, with urea as nitrogen source while α-Fe 2 O 3 nanoparticles as template and Fe source. The as-prepared NPCA calcined at 900 °C (NPCA-900) exhibits excellent electrocatalytic performance with high diffusion-limiting current density and stability comparable to those of commercial Pt/C catalysts in alkaline environment . The remarkable ORR performance of NPCA could be ascribed to the abundant porosity, large specific surface area (1060 m 2 g −1 ), as well as the doping of Fe-N (especially pyridinic N). The NPCA derived from cheap petroleum asphalt has good application future in the field of catalysis, while it may pave a new way to realize the clean and high value utilization of heavy oils.
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Frontiers of Chemical Science and Engineering
·
2017
·Vol. 11
·期 4
·613-623
·
IF 1.712
Tang Honggui,Li Shuangshuang,Gong Dandan,Guan Yi,Liu Yuan
Carbon deposition and sintering of active components such as nano particles are great challenges for Ni-based catalysts for CO methanation to generate synthetic natural gas from syngas. Facing the challenges, bimetallic catalysts with different Fe content derived from layered double hydroxide containing Ni, Fe, Mg, Al elements were prepared by co-precipitation method. Nanoparticles of Ni-Fe alloy were supported on mixed oxides of aluminium and magnesium after calcination and reduction. The catalysts were characterized by Brunner-Emmett-Teller (BET), X-ray diffraction, hydrogen temperature programmed reduction, inductively coupled plasma, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric techniques, and their catalytic activity for CO methanation was investigated. The results show that the Ni-Fe alloy catalysts exhibit better catalytic performance than monometallic catalysts except for the Ni4Fe-red catalyst. The Ni2Fe-red catalyst shows the highest CO conversion (100% at 260–350 °C), as well as the highest CH 4 selectivity (over 95% at 280–350 °C), owing to the formation of Ni-Fe alloy. In stability test, the Ni2Fe-red catalyst exhibits great improvement in both anti-sintering and resistance to carbon formation compared with the Ni0Fe-red catalyst. The strong interaction between Ni and Fe element in alloy and surface distribution of Fe element not only inhibits the sintering of nanoparticles but restrains the formation of Ni clusters.
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