Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol（DEG） used here plays dual role in synthesis ...Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol（DEG） used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction（XRD） and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.展开更多
Using a liquid-solid phase inversion method, a hybrid matrix poly（vinylidene fluoride）（PVDF） membrane was prepared with alumina（Al2O3） nanoparticle addition. Pd/Fe nanoparticles（NPs） were successfully immobili...Using a liquid-solid phase inversion method, a hybrid matrix poly（vinylidene fluoride）（PVDF） membrane was prepared with alumina（Al2O3） nanoparticle addition. Pd/Fe nanoparticles（NPs） were successfully immobilized on the Al2O3/PVDF membrane, which was characterized by Scanning Electron Microscopy（SEM） and Transmission Electron Microscopy（TEM）. The micrographs showed that the Pd/Fe NPs were dispersed homogeneously. Several important experimental parameters were optimized, including the mechanical properties, contact angle and surface area of Al2O3/PVDF composite membranes with different Al2O3 contents. At the same time, the ferrous ion concentration and the effect of hydrophilization were studied. The results showed that the modified Al2O3/PVDF membrane functioned well as a support. The Al2O3/PVDF membrane with immobilized Pd/Fe NPs exhibited high efficiency in terms of dichloroacetic acid（DCAA） dechlorination. Additionally, a reaction pathway for DCAA dechlorination by Pd/Fe NPs immobilized on the Al2O3/PVDF membrane system was proposed.展开更多
We herein used Fe3O4 nanoparticles（NPs） as an adsorption interface for the concurrent removal of gaseous benzene, toluene, ethylbenzene and m-xylene（BTEX） and sulfur dioxide（SO2）, at different relative humiditie...We herein used Fe3O4 nanoparticles（NPs） as an adsorption interface for the concurrent removal of gaseous benzene, toluene, ethylbenzene and m-xylene（BTEX） and sulfur dioxide（SO2）, at different relative humidities（RH）. X-ray diffraction, Brunauer-Emmett-Teller, and transmission electron microscopy were deployed for nanoparticle surface characterization.Mono-dispersed Fe3O4（Fe2O3·Fe O） NPs synthesized with oleic acid（OA） as surfactant, and uncoated poly-dispersed Fe3O4 NPs demonstrated comparable removal efficiencies.Adsorption experiments of BTEX on NPs were measured using gas chromatography equipped with flame ionization detection, which indicated high removal efficiencies（up to（95 ± 2）%） under dry conditions. The humidity effect and competitive adsorption were investigated using toluene as a model compound. It was observed that the removal efficiencies decreased as a function of the increase in RH, yet, under our experimental conditions, we observed（40 ± 4）% toluene removal at supersaturation for Fe3O4 NPs, and toluene removal of（83 ± 4）% to（59 ± 6）%, for OA-Fe3O4 NPs. In the presence of SO2, the toluene uptake was reduced under dry conditions to（89 ± 2）% and（75 ± 1）% for the uncoated and coated NPs, respectively, depicting competitive adsorption. At RH 〉 100%,competitive adsorption reduced the removal efficiency to（27 ± 1）% for uncoated NPs whereas OA-Fe3O4 NPs exhibited moderate efficiency loss of（55 ± 2）% at supersaturation.Results point to heterogeneous water coverage on the NP surface. The magnetic property of magnetite facilitated the recovery of both types of NPs, without the loss in efficiency when recycled and reused.展开更多
The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy...The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.展开更多
In this paper,we have reported the synthesis of FeS2 of higher band gap energy（2.75 eV） by using capping reagent and its successive application in organic-inorganic based hybrid solar cells.Hydrothermal route was ad...In this paper,we have reported the synthesis of FeS2 of higher band gap energy（2.75 eV） by using capping reagent and its successive application in organic-inorganic based hybrid solar cells.Hydrothermal route was adopted for preparing iron pyrite（FeS2） nanoparticles with capping reagent PEG-400.The quality of synthesized FeS2 material was confirmed by X-ray diffraction,field emission scanning electron microscopy,transmission electron microscopy,Fourier transform infrared,thermogravimetric analyzer,and Raman study.The optical band gap energy and electro-chemical band gap energy of the synthesized FeS2 were investigated by UV-vis spectrophotometry and cyclic voltammetry.Finally band gap engineered FeS2 has been successfully used in conjunction with conjugated polymer MEHPPV for harvesting solar energy.The energy conversion efficiency was obtained as 0.064%with a fill-factor of 0.52.展开更多
Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on ...Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe_2O_3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe_2O_3 particles were encapsulated in polystyrene(PSt) successfully.展开更多
We report a novel chemical vapor deposition （CVD） based strategy to synthesize carbon-coated Fe203 nanoparticles dispersed on graphene sheets （Fe2Og@C@G）. Graphene sheets with high surface area and aspect ratio ar...We report a novel chemical vapor deposition （CVD） based strategy to synthesize carbon-coated Fe203 nanoparticles dispersed on graphene sheets （Fe2Og@C@G）. Graphene sheets with high surface area and aspect ratio are chosen as space restrictor to prevent the sintering and aggregation of nanoparticles during high temperature treatments （800 ℃）. In the resulting nanocomposite, each individual Fe2O3 nanoparticle （5 to 20 nm in diameter） is uniformly coated with a continuous and thin （two to five layers） graphitic carbon shell. Further, the core-shell nanoparticles are evenly distributed on graphene sheets. When used as anode materials for lithium ion batteries, the conductive-additive-free Fe2OB@C@G electrode shows outstanding Li＋ storage properties with large reversible specific capacity （864 mAh/g after 100 cycles）, excellent cyclic stability （120% retention after 100 cycles at 100 mA/g）, high Coulombic efficiency （-99%）, and good rate capability.展开更多
A biosensor based on hemoglobin-Fe304@SiO2 nanoparticle bioconjunctions modified indium-tin-oxide （Hb/Fe3O4@SiOz/ITO） electrode was fabricated to determine the concentration of H202. UV-vis absorption spectra, fouri...A biosensor based on hemoglobin-Fe304@SiO2 nanoparticle bioconjunctions modified indium-tin-oxide （Hb/Fe3O4@SiOz/ITO） electrode was fabricated to determine the concentration of H202. UV-vis absorption spectra, fourier transform infrared （FT-IR） spectroscopy, cyclic voltammetry （CV） and high-resolution transmission electron microscopy （HRTEM） were used to characterize the bioconjunction of Fe3O4@SiO2 with Hb. Experimental results demonstrate that the immobilized Hb on the Fe3O4@SiO2 matrix retained its native structure well. In addition, Fe3O4@SiO2 nanoparticles （NPs） are very effective in facilitating electron transfer of the immobilized enzyme, which can be attributed to the unique nanostructure and larger surface area of the Fe304@SiO2 NPs. The biosensor displayed good performance for the detection of H2O2 with a wide linear range from 2.03×10^-6 to 4.05×10^3 mol/L and a detection limit of 0.32 μmol/L. The resulting biosensor exhibited fast amperometric response, good stability, reproducibility, and selectivity to H2O2.展开更多
Planar micro-supercapacitors show great potential as the energy storage unit in miniaturized electronic devices. Asymmetric structures have been widely inves- tigated in micro-supercapacitors, and carbon-based materia...Planar micro-supercapacitors show great potential as the energy storage unit in miniaturized electronic devices. Asymmetric structures have been widely inves- tigated in micro-supercapacitors, and carbon-based materials are commonly applied in the electrodes. To integrate different metal oxides in both electrodes in micro-supercapacitors, the critical challenge is the pairing of different faradic metal oxides. Herein, we propose a strategy of matching the voltage and capadtance of two faradic materials that are fully integrated into one high-performance asymmetric micro-supercapacitor by a facile and controllable fabrication process. The fabricated micro-supercapacitors employ MnO2 as the positive active material and Fe203 as the negative active material, respectively. The planar asymmetric micro-supercapacitors possess a high capacitance of 60 F-cm-3, a high energy density of 12 mW.h.cm-3, and a broad operation voltage range up to 1.2 V.展开更多
In this paper, the laccase immobilized on Fe304@SiO2-NH2 nanoparticles was successfully prepared by the glutaraldehyde cross-linking method. The degradations of 2,4-diehlorophenol （2,4-DCP） catalyzed by laccase and ...In this paper, the laccase immobilized on Fe304@SiO2-NH2 nanoparticles was successfully prepared by the glutaraldehyde cross-linking method. The degradations of 2,4-diehlorophenol （2,4-DCP） catalyzed by laccase and immobilized laccase were carried out. The optimal conditions regarding degradation efficiency were also discussed, which include reaction time, pH value, temperature, concentration of 2,4-DCP and laccase. When laccase was immobilized on Fe304@SiO2-NH2 carrier by crosslinking with glutaraldehyde, the stability and repetition were im- proved significantly. The removal efficiency of 2,4-DCP by immobilized laccase still remained over 59% after six cycles of operation. Degradation of 2,4-DCP is a first-order reaction and the activation energies of 2,4-DCP catalyzed by laccase and immobilized laccase are 51.93 kJ·mol-1 strate the immobilized laccase had a faster degradation Fe304@MSS-NH2 can promote the degradation reaction. and 44.12 kJ·mol-1, respectively. The results demonrate than the free laccase; the magnetic carrier展开更多
Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have ...Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have been limited by insufficient durability in both alkaline and acidic environments.In particular,limited attention has been paid to stabilizing iron-based catalysts by introducing additional metal by the alloying effect.Herein,we report bimetallic Fe_(2)Mo nanoparticles on N-doped carbon(Fe_(2)Mo/NC)as an efficient and ultra-stable ORR electrocatalyst for the first time.The Fe_(2)Mo/NC catalyst shows high selectivity for a four-electron pathway of ORR and remarkable electrocatalytic activity with high kinetics current density and half-wave potential as well as low Tafel slope in both acidic and alkaline medias.It demonstrates excellent long-term durability with no activity loss even after 10,000 potential cycles.Density functional theory(DFT)calculations have confirmed the modulated electronic structure of formed Fe_(2)Mo,which supports the electron-rich structure for the ORR process.Meanwhile,the mutual protection between Fe and Mo sites guarantees efficient electron transfer and long-term stability,especially under the alkaline environment.This work has supplied an effective strategy to solve the dilemma between high electroactivity and long-term durability for the Fe-based electrocatalysts,which opens a new direction of developing novel electrocatalyst systems for future research.展开更多
基金the Council of Scientific and Industrial Research, India for the award of senior research fellowship (File. 09/1077/(0001)/ 2012/EMR-1)
文摘Superparamagnetic monodisperse Mg0.8Mn0.2Fe2O4 nanoparticles have been successfully synthesized in liquid polyol at elevated temperature of 200 °C. Diethylene glycol（DEG） used here plays dual role in synthesis as it acts as reducing agent and alternatively coats the surface of nanoparticles while synthesis and thereby maintaining uniform size and dispersibility. Powder X-ray diffraction（XRD） and magnetic measurements showed that the sample is cubic spinel and superparamagnetic at room temperature. Raman spectra confirmed the formation of the Mg0.8Mn0.2Fe2O4 nanoparticles.The nanoparticles exhibit very good stability in water due to in situ coating with DEG molecules.
基金supported by the Nature Science Foundation of Heilongjiang Province (No. B201410)the Postdoctoral Foundation Project of Heilongjiang Province (No. LBH-Z13128)+3 种基金the Science and Technology Research Program of Education Bureau of Heilongjiang Province (No. 12531206)the Special Scientific Research Projects of Harbin Normal University (12XQXG02)the National Nature Science Foundation of China (No. 41030743)the National Nature Science Foundation of China (No. 42171217)
文摘Using a liquid-solid phase inversion method, a hybrid matrix poly（vinylidene fluoride）（PVDF） membrane was prepared with alumina（Al2O3） nanoparticle addition. Pd/Fe nanoparticles（NPs） were successfully immobilized on the Al2O3/PVDF membrane, which was characterized by Scanning Electron Microscopy（SEM） and Transmission Electron Microscopy（TEM）. The micrographs showed that the Pd/Fe NPs were dispersed homogeneously. Several important experimental parameters were optimized, including the mechanical properties, contact angle and surface area of Al2O3/PVDF composite membranes with different Al2O3 contents. At the same time, the ferrous ion concentration and the effect of hydrophilization were studied. The results showed that the modified Al2O3/PVDF membrane functioned well as a support. The Al2O3/PVDF membrane with immobilized Pd/Fe NPs exhibited high efficiency in terms of dichloroacetic acid（DCAA） dechlorination. Additionally, a reaction pathway for DCAA dechlorination by Pd/Fe NPs immobilized on the Al2O3/PVDF membrane system was proposed.
基金the support of the following Canadian funding agencies: NSERC, FRQNT and CFI
文摘We herein used Fe3O4 nanoparticles（NPs） as an adsorption interface for the concurrent removal of gaseous benzene, toluene, ethylbenzene and m-xylene（BTEX） and sulfur dioxide（SO2）, at different relative humidities（RH）. X-ray diffraction, Brunauer-Emmett-Teller, and transmission electron microscopy were deployed for nanoparticle surface characterization.Mono-dispersed Fe3O4（Fe2O3·Fe O） NPs synthesized with oleic acid（OA） as surfactant, and uncoated poly-dispersed Fe3O4 NPs demonstrated comparable removal efficiencies.Adsorption experiments of BTEX on NPs were measured using gas chromatography equipped with flame ionization detection, which indicated high removal efficiencies（up to（95 ± 2）%） under dry conditions. The humidity effect and competitive adsorption were investigated using toluene as a model compound. It was observed that the removal efficiencies decreased as a function of the increase in RH, yet, under our experimental conditions, we observed（40 ± 4）% toluene removal at supersaturation for Fe3O4 NPs, and toluene removal of（83 ± 4）% to（59 ± 6）%, for OA-Fe3O4 NPs. In the presence of SO2, the toluene uptake was reduced under dry conditions to（89 ± 2）% and（75 ± 1）% for the uncoated and coated NPs, respectively, depicting competitive adsorption. At RH 〉 100%,competitive adsorption reduced the removal efficiency to（27 ± 1）% for uncoated NPs whereas OA-Fe3O4 NPs exhibited moderate efficiency loss of（55 ± 2）% at supersaturation.Results point to heterogeneous water coverage on the NP surface. The magnetic property of magnetite facilitated the recovery of both types of NPs, without the loss in efficiency when recycled and reused.
基金Funded by the National Natural Science Foundation of China (50672089)the Encouraging Foundation for the Scientific Research of the Excellent Young and Middleaged Scientists in Shandong Province(2006BS04034)
文摘The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.
基金supported by University Grants Commission (UGC),Govt.of India under project 39-508/2010(SR)
文摘In this paper,we have reported the synthesis of FeS2 of higher band gap energy（2.75 eV） by using capping reagent and its successive application in organic-inorganic based hybrid solar cells.Hydrothermal route was adopted for preparing iron pyrite（FeS2） nanoparticles with capping reagent PEG-400.The quality of synthesized FeS2 material was confirmed by X-ray diffraction,field emission scanning electron microscopy,transmission electron microscopy,Fourier transform infrared,thermogravimetric analyzer,and Raman study.The optical band gap energy and electro-chemical band gap energy of the synthesized FeS2 were investigated by UV-vis spectrophotometry and cyclic voltammetry.Finally band gap engineered FeS2 has been successfully used in conjunction with conjugated polymer MEHPPV for harvesting solar energy.The energy conversion efficiency was obtained as 0.064%with a fill-factor of 0.52.
基金Supported by the National Natural Science Foundation of China(No. 2 99730 2 6 and 2 0 0 75 0 2 8) ,K.C.Wang Post-Doctoral Research Award Fund of Chinese Academ y of Sciences,and China Postdoctoral Science Foundation
文摘Fe_2O_3 sol with the particle diameter of 3-5 nm was flocculated by the addition of SDS, and the flocculate formed was redispersed by the further addition of that surfactant. Thus the surfactant bilayer was formed on the surface of Fe_2O_3. The emulsion polymerization of styrene(St) adsolubilized on the surfactant adsorbed bilayer was carried out by initiator potassium persulfate(KPS). The UV-Vis and surface photovoltage spectra(SPS) indicate that the Fe_2O_3 particles were encapsulated in polystyrene(PSt) successfully.
文摘We report a novel chemical vapor deposition （CVD） based strategy to synthesize carbon-coated Fe203 nanoparticles dispersed on graphene sheets （Fe2Og@C@G）. Graphene sheets with high surface area and aspect ratio are chosen as space restrictor to prevent the sintering and aggregation of nanoparticles during high temperature treatments （800 ℃）. In the resulting nanocomposite, each individual Fe2O3 nanoparticle （5 to 20 nm in diameter） is uniformly coated with a continuous and thin （two to five layers） graphitic carbon shell. Further, the core-shell nanoparticles are evenly distributed on graphene sheets. When used as anode materials for lithium ion batteries, the conductive-additive-free Fe2OB@C@G electrode shows outstanding Li＋ storage properties with large reversible specific capacity （864 mAh/g after 100 cycles）, excellent cyclic stability （120% retention after 100 cycles at 100 mA/g）, high Coulombic efficiency （-99%）, and good rate capability.
基金Project supported by the National Natural Science Foundation of China （Nos. 20905010, 20905016）, Jiangsu Provincial Natural Science Foundation （No. BK2008147）, Guangxi Natural Science Foundation （No. 0991082）, and China Postdoctoral Science Foundation （No. 20100471293）.
文摘A biosensor based on hemoglobin-Fe304@SiO2 nanoparticle bioconjunctions modified indium-tin-oxide （Hb/Fe3O4@SiOz/ITO） electrode was fabricated to determine the concentration of H202. UV-vis absorption spectra, fourier transform infrared （FT-IR） spectroscopy, cyclic voltammetry （CV） and high-resolution transmission electron microscopy （HRTEM） were used to characterize the bioconjunction of Fe3O4@SiO2 with Hb. Experimental results demonstrate that the immobilized Hb on the Fe3O4@SiO2 matrix retained its native structure well. In addition, Fe3O4@SiO2 nanoparticles （NPs） are very effective in facilitating electron transfer of the immobilized enzyme, which can be attributed to the unique nanostructure and larger surface area of the Fe304@SiO2 NPs. The biosensor displayed good performance for the detection of H2O2 with a wide linear range from 2.03×10^-6 to 4.05×10^3 mol/L and a detection limit of 0.32 μmol/L. The resulting biosensor exhibited fast amperometric response, good stability, reproducibility, and selectivity to H2O2.
基金This work was supported by the National Key Research and Development Program of China （No. 2016YFA0202603）, the National Basic Research Program of China （No. 2013CB934103）, the Programme of Introducing Talents of Discipline to Universities （No. B17034）, the National Natural Science Foundation of China （Nos. 51521001, 51502227, 51579198, and 51302203）, the National Natural Science Fund for Distinguished Young Scholars （No. 51425204）, and the Fundamental Research Funds for the Central Universities （WUT： 2016III001, 2016III005, 2016III006）.
文摘Planar micro-supercapacitors show great potential as the energy storage unit in miniaturized electronic devices. Asymmetric structures have been widely inves- tigated in micro-supercapacitors, and carbon-based materials are commonly applied in the electrodes. To integrate different metal oxides in both electrodes in micro-supercapacitors, the critical challenge is the pairing of different faradic metal oxides. Herein, we propose a strategy of matching the voltage and capadtance of two faradic materials that are fully integrated into one high-performance asymmetric micro-supercapacitor by a facile and controllable fabrication process. The fabricated micro-supercapacitors employ MnO2 as the positive active material and Fe203 as the negative active material, respectively. The planar asymmetric micro-supercapacitors possess a high capacitance of 60 F-cm-3, a high energy density of 12 mW.h.cm-3, and a broad operation voltage range up to 1.2 V.
基金support from the National Natural Science Foundation of China （Grant No. 20971043 and No. 20577010）, the Open Project Program of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University.
文摘In this paper, the laccase immobilized on Fe304@SiO2-NH2 nanoparticles was successfully prepared by the glutaraldehyde cross-linking method. The degradations of 2,4-diehlorophenol （2,4-DCP） catalyzed by laccase and immobilized laccase were carried out. The optimal conditions regarding degradation efficiency were also discussed, which include reaction time, pH value, temperature, concentration of 2,4-DCP and laccase. When laccase was immobilized on Fe304@SiO2-NH2 carrier by crosslinking with glutaraldehyde, the stability and repetition were im- proved significantly. The removal efficiency of 2,4-DCP by immobilized laccase still remained over 59% after six cycles of operation. Degradation of 2,4-DCP is a first-order reaction and the activation energies of 2,4-DCP catalyzed by laccase and immobilized laccase are 51.93 kJ·mol-1 strate the immobilized laccase had a faster degradation Fe304@MSS-NH2 can promote the degradation reaction. and 44.12 kJ·mol-1, respectively. The results demonrate than the free laccase; the magnetic carrier
基金supported by the National Key R&D Program of China(No.2021YFA1501101)the National Nature Science Foundation of China(Nos.21862011,21771156,and 51864024)+4 种基金Yunnan province(No.2019FI003)the Shenzhen Knowledge Innovation Program(Basic Research,No.JCYJ20190808181205752)the Research Grants Council(RGC)of the Hong Kong Special Administrative Region,China(Project No.CityU 11206520)the National Natural Science Foundation of China/RGC Joint Research Scheme(No.N_PolyU502/21)the funding for Projects of Strategic Importance of The Hong Kong Polytechnic University(Project Code:1-ZE2V).
文摘Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have been limited by insufficient durability in both alkaline and acidic environments.In particular,limited attention has been paid to stabilizing iron-based catalysts by introducing additional metal by the alloying effect.Herein,we report bimetallic Fe_(2)Mo nanoparticles on N-doped carbon(Fe_(2)Mo/NC)as an efficient and ultra-stable ORR electrocatalyst for the first time.The Fe_(2)Mo/NC catalyst shows high selectivity for a four-electron pathway of ORR and remarkable electrocatalytic activity with high kinetics current density and half-wave potential as well as low Tafel slope in both acidic and alkaline medias.It demonstrates excellent long-term durability with no activity loss even after 10,000 potential cycles.Density functional theory(DFT)calculations have confirmed the modulated electronic structure of formed Fe_(2)Mo,which supports the electron-rich structure for the ORR process.Meanwhile,the mutual protection between Fe and Mo sites guarantees efficient electron transfer and long-term stability,especially under the alkaline environment.This work has supplied an effective strategy to solve the dilemma between high electroactivity and long-term durability for the Fe-based electrocatalysts,which opens a new direction of developing novel electrocatalyst systems for future research.
