Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 46
·23207-23212
·
IF 7.443
Ningyan Cheng,Qian Liu,Abdullah M. Asiri,Wei Xing,Xuping Sun
The efficiency of water splitting is mainly limited by the low rate of the oxygen evolution reaction (OER) and it is thus of great importance but still remains a huge challenge to develop efficient OER catalysts capable of delivering high current densities at low overpotentials. Herein, we describe our recent finding that a Fe-doped Ni3S2 particle film with 11.8% Fe-content hydrothermally grown on nickel foam (Fe11.8%-Ni3S2/NF) behaves as a highly active robust oxygen evolution electrode in strongly alkaline media. This electrode needs an overpotential of only 253 mV to achieve 100 mA cm−2 with a Tafel slope of 65.5 mV dec−1 and maintains its catalytic activity for at least 14 h in 1 M KOH, and the NiOOH and FeOOH formed at the Fe11.8%-Ni3S2 surface are the actual catalytic sites. Notably, it also operates efficiently and stably in 30 wt% KOH, capable of affording very high current densities of 500 and 1000 mA cm−2 at small overpotentials of 238 and 269 mV, respectively, with a faradaic efficiency of 100%.
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Analytical Methods
·
2015
·Vol. 7
·期 12
·4939-4946
·
IF 1.821
Huan Wang,Si-Yao Liu,Xiao-Jun Lv,Rui Ma,Zhi-Qi Zhang
Unique ternary single core–double shell structured magnetic microspheres of Fe3O4@SiO2@Fe–pamoate were successfully fabricated via a step-by-step assembly strategy. The procedures involved initial pre-treatment of silica-coated magnetic cores with carboxyl groups to functionalize the magnetic microspheres, and subsequent alternating treatments with Fe3+ and pamoic acid solutions for the growth of Fe–pamoate complexes on the microsphere surface to form Fe3O4@SiO2@Fe–pamoate magnetic microspheres. Characterization using various techniques demonstrated that the microspheres were porous, thermally stable, and possessed a single core–double shell sandwich structure. The as-synthesized materials possessed a bifunctional character derived from the magnetic properties of Fe3O4 nanoparticles and the high porosity of Fe–pamoate, making them excellent candidates as adsorbents for the magnetic enrichment of trace analytes. The potential applicability of the microspheres was demonstrated by preconcentrating sulfonamide antibiotics from environmental water samples prior to high-performance liquid chromatography analysis. The method combining enrichment with high-performance liquid chromatography had higher precision (relative standard deviations 1.4–12.3%), lower detection limits (0.08–0.12 ng mL−1), and good linearity (correlation coefficients higher than 0.9947) for five sulfonamide antibiotics investigated. Average recoveries at three spiked levels were in the range of 86.3 to 99.7% with relative standard deviations below 12.3%.
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ACS Catalysis
·
2014
·
IF 7.572
Mei-Qing Wang,Wei-Hua Yang,Hong-Hui Wang,Chi Chen,Zhi-You Zhou,Shi-Gang Sun
Aimed at developing a highly active and stable non-precious metal catalyst (NPMC) for oxygen reduction reaction (ORR) in acidic proton-exchange membrane fuel cells (PEMFCs), a novel NPMC was prepared by pyrolyzing a composite of carbon-supported Fe-doped graphitic carbon nitride (Fe–g-C3N4@C) above 700 °C. In this paper, the influence of the pyrolysis temperature and Fe content on ORR performance was investigated. Rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) studies reveal that, with a half-wave potential of 0.75 V [versus reversible hydrogen electrode (RHE)] and a H2O2 yield of 2.6% at 0.4 V, the as-synthesized catalyst heat-treated at 750 °C with a Fe salt/dicyandiamide (DCD) mass ratio of 10% displays the optimal ORR activity and selectivity. Furthermore, the pyrolyzed Fe–N–C composite exhibits superior durability in comparison to that of commercial 20 wt % Pt/C in acidic medium, making it a good candidate for an ORR electrocatalyst in PEMFCs.
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RSC Advances
·
2015
·Vol. 5
·期 82
·67031-67040
·
IF 3.84
Z. Y. Wu,X. A. Fan,G. Q. Li,J. Wang,Z. H. Gan
Core–shell structured Fe-6.5 wt% Si/SiO2 particles and intergranular insulated Fe-6.5 wt% Si/SiO2 composite compacts with tunable insulating layer thickness were prepared by in situ chemical deposition combined with a subsequent spark plasma sintering process. Most of conductive Fe-6.5 wt% Si alloy particles were coated with a SiO2 insulating layer in the Fe-6.5 wt% Si/SiO2 composite compacts. The SiO2 insulating layer could increase the electrical resistivity and reduce the effective radius of the eddy current in Fe-6.5 wt% Si/SiO2 composite compacts. Therefore, the intergranular insulated Fe-6.5 wt% Si/SiO2 composite compacts presented lower core loss than those of Fe-6.5 wt% Si compacts without SiO2 insulating layer. Based on this, several types of Fe-6.5 wt% Si/SiO2 core–shell particles and intergranular insulated Fe-6.5 wt% Si/SiO2 composite compacts (with various SiO2 insulating layer thicknesses) were selectively prepared by simply varying the TEOS concentration (the volume of TEOS for each gram of Fe-6.5 wt% Si particles, ml g−1). The results indicated that the thickness of the SiO2 layer and electrical resistivity of Fe-6.5 wt% Si/SiO2 composite compacts increased with increasing the TEOS concentration from 0.1 to 0.4 ml g−1, while saturation magnetization, relative permeability and core loss displayed the reverse tendencies. The as-prepared intergranular insulated Fe-6.5 wt% Si/SiO2 composite compacts exhibited excellent magnetic properties, which inspire us to develop new high silicon containing soft magnetic cores which can be widely used in various electromagnetic devices.
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JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
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2014
·
IF 3.679
Sheng-jie Xia,Xiao-bo Zhou,Wei Shi,Guo-xiang Pan,Zhe-ming Ni
Three transition metal oxides (Fe 3 O 4 , CeO 2 and SnO 2 ) modified Zn/Ti–layered double hydroxides (LDHs) were successfully synthesized. These materials were characterized by powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), Brunauer–Emmett–Teller (BET) and UV–vis diffuse reflectance spectrum (UV–vis) for the purpose of confirming the formation of good crystal structure. Comparing with original layered double hydroxides, the transition metal oxides modified Zn/Ti layered double hydroxide materials show narrower band gap, larger surface area, smaller pore volume, pore size distribution, and higher removal efficiency for acid red 14 under visible light. The decomposition efficiency of acid red 14 was all over 92% after 120 min. In addition, the thermal regeneration for re-use of layered double hydroxide materials after photodegradation was feasible for at least four cycles (degradation amount still all over 80%). Furthermore, the kinetic parameters, intermediates and possible photocatalytic pathways for acid red 14 decomposed by these transition metal oxides modified Zn/Ti layered double hydroxide materials were also investigated carefully.
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RSC Advances
·
2016
·Vol. 6
·期 43
·37110-37117
·
IF 3.289
Mingjuan Han,Zheng Gu,Chong Chen,Zuowang Wu,Yigen Que,Qiang Wang,Hui Wan,Guofeng Guan
A new, simple and effective strategy to confine dicationic acid ionic liquids (DAILs, 1,4-bis[3-(propyl-3-sulfonate) imidazolium] butane hydrogen sulfate) in the cages of MIL-100(Fe) frameworks was constructed. The target catalyst, defined as MIL-100(Fe)@DAILs, was characterized by XRD, FTIR, SEM, TEM, EA, TGA and N2 adsorption–desorption. Meanwhile, the catalytic activity of the MIL-100(Fe)@DAILs catalyst was evaluated by the esterification reaction with oleic acid and methanol. The results indicated that the DAILs had been effectively encapsulated within the cages of the MIL-100(Fe) frameworks. Moreover, the influence of reaction time, reaction temperature, molar ratio of methanol to oleic acid and catalyst dosage on the conversion of oleic acid was studied by univariate analysis. The conversion of oleic acid decreased from 93.5% to 86.0% when the catalyst was reused five times, which indicated that the target catalyst possessed higher catalytic activity and superior catalytic activity. Finally, an esterification mechanism catalyzed by this novel catalyst was illustrated.
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Materials Research Express
·
2017
·Vol. 4
·期 8
·085009
·
IF 1.068
Zongtang Liu,Chenggang Gu,Yongrong Bian,Xin Jiang,Yufeng Sun,Zhenghao Fei,Jingtao Dai
In this study, Fe/Ni bimetallic nanoparticles were supported on the attapulgite (A-Fe/Ni) to enhance the degradation reactivity of decabrominated diphenyl ether (BDE209) in aqueous solution. The Fe/Ni nanoparticles were well distributed on the attapulgite surface with an average diameter of 20–40 nm. The removal percentage of BDE209 by A-Fe/Ni was 1.59 times higher than Fe/Ni nanoparticles alone because attapulgite could act as supporting material to disperse Fe/Ni nanoparticles and prevent Fe/Ni nanoparticles from aggregation. The degradation kinetics for BDE209 debromination by A-Fe/Ni could be well described by a pseudo-first-order model, and the debromination rate constant of BDE209 increased with increasing the dosage of A-Fe/Ni, water/THF ratio, and decreasing the initial BDE209 concentration and solution pH. The degradation products were identified using a third-order polynomial regression equation between the experimental and reference gas chromatography relative retention times. Stepwise debromination from n-bromo-DE to (n − 1)-bromo-DE was a possible pathway with bromines being substituted sequentially by hydrogen. The preferred elimination of bromines of BDE209 by A-Fe/Ni followed the debromination preference of para-Br > meta-Br > ortho-Br. The results provide evidences for understanding the debromination mechanism of polybrominated diphenyl ether by clay-supported Fe/Ni nanoparticles.
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MOLECULES
·
2017
·Vol. 22
·期 6
·920
·
IF 2.861
Youxun Liu,Yuanyuan Geng,Mingyang Yan,Juan Huang
The successful encapsulation of 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), a well-known laccase mediator, within a mesoporous metal-organic framework sample (i.e., MIL-100(Fe)) was achieved using a one-pot hydrothermal synthetic method. The as-prepared ABTS@MIL-100(Fe) was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, nitrogen sorption, and cyclic voltammetry (CV). Our ABTS@MIL-100(Fe)-based electrode exhibited an excellent electrochemical response, indicating that MIL-100(Fe) provides an appropriate microenvironment for the immobilization and electroactivity of ABTS molecules. ABTS@MIL-100(Fe) was then evaluated as an immobilized laccase mediator for dye removal using indigo carmine (IC) as a model dye. Through the application of laccase in combination with a free (ABTS) or immobilized (ABTS@MIL-100(Fe)) mediator, decolorization yields of 95% and 94%, respectively, were obtained for IC after 50 min. In addition, following seven reuse cycles of ABTS@MIL-100(Fe) for dye treatment, a decolorization yield of 74% was obtained. Dye decolorization occurred through the breakdown of the chromophoric group by the Laccase/ABTS@MIL-100(Fe) system, and a catalytic mechanism was proposed. We therefore expect that the stability, reusability, and validity of ABTS@MIL-100(Fe) as a laccase mediator potentially render it a promising tool for dye removal, in addition to reducing the high running costs and potential toxicity associated with synthetic mediators.Keywords:laccase;ABTS;metal-organic framework;mediator;decolorization
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高影响因子
Journal of Saudi Chemical Society
·
2016
·
IF 1.978
Yingting Wang,Jiangfeng Huang,Xiaomeng Xia,Xinhua Peng
A highly efficient catalyst Fe–Co/sulfonated polystyrene (Fe–Co/SPS) was introduced and synthesized, which catalyzed BV oxidation of ketones with aqueous hydrogen peroxide to give the corresponding lactones in high yield and selectivity. Solid acid catalyst of Fe–Co/SPS has been prepared by using the 98-wt% sulfuric acid as the sulfonating agent and CoCl 2 combined FeCl 3 as sources of metal ions. Various physical–chemical characterizations including FT-IR, XRD, SEM and TGA, revealed that bimetallic ions Fe 3+ –Co 2+ species in the sulfonated polystyrene framework were responsible for the catalytic activities. The BV reaction catalyzed by Fe–Co/SPS highlighted the special effects between metal ions and protonic acids as well as solvent-free heterogeneous catalytic oxidation with excellent conversion.
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RSC Advances
·
2016
·Vol. 6
·期 32
·27039-27046
·
IF 3.289
Honglin Yao,Qianqian Ding,Hongjian Zhou,Zhenfu Zhao,Gang Liu,Guozhong Wang
In this study, mesoporous amino-group functionalised iron/silica hollow spheres (Fe/SiO2–NH2 HSs) were successfully developed as a magnetic absorbent for the highly effective removal of Cr(VI) ions. The Fe/SiO2–NH2 HSs were synthesized using monodispersed silica colloids as a chemical template, followed by a one-pot hydrothermal treatment, hydrogen reduction and surface modification with an amino silane coupling agent. The Fe/SiO2–NH2 HSs have a diameter of ca. 950 nm and a shell thickness of ca. 60 nm, and the surfaces were composed of Fe and SiO2 units with amino functional groups. Meanwhile, the ferromagnetic property endowed them with easy recyclability for practical applications. The Fe/SiO2–NH2 HSs exhibited significantly improved ability to remove pollutant Cr(VI) and methyl orange. The removal percentage of Cr(VI) (8 mg L−1) could reach 98.3% in just 5 min using Fe/SiO2–NH2 HSs; however, only 10% of Cr(VI) were removed using the unmodified samples. XPS analysis suggested that the removal of Cr(VI) was attributed to the adsorption and reduction synergistic process of the Fe/SiO2–NH2 HSs. During the process, an electrostatic attraction occurred between the positively charged amino-groups and the negatively charged pollutant species in the aqueous solution, and adsorbed Cr(VI) ions were reduced to Cr(III) species by the iron of Fe/SiO2–NH2 HSs.
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ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Yuan Pan,Yunqi Liu,Yan Lin,Chenguang Liu
The enhancement of catalytic performance of cobalt phosphide-based catalysts for the hydrogen evolution reaction (HER) is still challenging. In this work, the doping effect of some transition metal (M = Fe, Ni, Cu) on the electrocatalytic performance of the M–Co2P/NCNTs (NCNTs, nitrogen-doped carbon nanotubes) hybrid catalysts for the HER was studied systematically. The M–Co2P/NCNTs hybrid catalysts were synthesized via a simple in situ thermal decomposition process. A series of techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, transmission electron microscopy, and N2 sorption were used to characterize the as-synthesized M–Co2P/NCNTs hybrid catalysts. Electrochemical measurements showed the catalytic performance according to the following order of Fe–Co2P/NCNTs > Ni–Co2P/NCNTs > Cu–Co2P/NCNTs, which can be ascribed to the difference of structure, morphology, and electronic property after doping. The doping of Fe atoms promote the growth of the [111] crystal plane, resulting in a large specific area and exposing more catalytic active sites. Meanwhile, the Feδ+ has the highest positive charge among all the M–Co2P/NCNTs hybrid catalysts after doping. All these changes can be used to contribute the highest electrocatalytic activity of the Fe–Co2P/NCNTs hybrid catalyst for HER. Furthermore, an optimal HER electrocatalytic activity was obtained by adjusting the doping ratio of Fe atoms. Our current research indicates that the doping of metal is also an important strategy to improve the electrocatalytic activity for the HER.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Qingmin Hu,Sen Wang,Zhe Gao,Yunqin Li,Qian Zhang,Qun Xiang,Yong Qin
The decoration of noble metal-based catalysts with metal oxides can improve their catalytic performance for the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol (COL) due to the interaction between the noble metal and metal oxides. Here, we used atomic layer deposition (ALD) to decorate Pt nanoparticles precisely with Fe oxides. The selectivity to COL increased from 45% for the bare Pt catalyst to 84% for the Pt-based catalyst after 30 cycles of decoration with Fe oxide by ALD. A series of characterizations demonstrated that the precise blocking of low coordinated Pt sites with Fe oxide by ALD, generating Pt-FeO x interfacial perimeter sites, and the interaction between the Pt nanoparticles and Fe oxide led to high selectivity to COL. This precise decoration and the formation of interfacial perimeter sites by ALD provide a promising route for the design of advanced catalysts.
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