Spinel ferrites NiFeOsupported Ru catalysts have been prepared via a simple sol–gel route and applied for converting biomass-derived furfural to 2-methylfuran. The as-prepared catalysts were characterized by thermogr...Spinel ferrites NiFeOsupported Ru catalysts have been prepared via a simple sol–gel route and applied for converting biomass-derived furfural to 2-methylfuran. The as-prepared catalysts were characterized by thermogravimetric analysis（TG）, Nadsorption–desorption, X-ray diffraction（XRD）, scanning electronic microscopy（SEM）, and X-ray photoelectron spectroscopy（XPS）. Results showed that the catalysts had well-dispersed Ru active sites and large surface area for calcination temperature ranging from 300 to 500 ℃. The conversion of biomass-derived furfural into 2-methylfuran was conducted over Ru/NiFeOthrough catalytic transfer hydrogenation in liquid-phase with 2-propanol as the hydrogen source. A significantly enhanced activity and increased 2-methylfuran yield have been achieved in this study. Under mild conditions（180 ℃ and 2.1 MPa N）, the conversion of furfural exceeds 97% and 2-methylfuran yield was up to 83% over the catalyst containing 8 wt% Ru. After five repeated uses, the catalytic activity and the corresponding product yield remained almost unchanged. The excellent catalytic activity and recycling performance provide a broad prospects for various practical applications.展开更多
The extensive use of toluene stimulates the effective detection by sensitive gas sensors based on unique materials.Here,hierarchical flower-like NiFe_(2)O_(4) with core-shell architecture was synthesized by a facile h...The extensive use of toluene stimulates the effective detection by sensitive gas sensors based on unique materials.Here,hierarchical flower-like NiFe_(2)O_(4) with core-shell architecture was synthesized by a facile hydrothermal method in the presence of urea and NH4 F.The controllable experiments indicated that the burr spheres and football-like samples were produced with individual urea or NH4 F.The flower-like NiFe_(2)O_(4) sensor exhibited outstanding sensitivity of 19.95 to 100×10^(-6) toluene with low detection limit(1×10^(-6)).Furthermore,the sensor showed superior sensing selectivity and longterm stability to toluene.The excellent sensing properties could largely arise from a combination of high surface area,numerous active sites,porous structures,and the native catalytic characteristics of NiFe2 O4 to facilitate toluene molecules adsorption,diffusion,and reaction.展开更多
This work investigated the effect of dysprosium(Dy)ions on the structural,microstructural and magnetic properties of nickel nanospinelferrite,NiFe2 O4.The nanoparticles(NPs)of NiDyxFe(2-x)O4(0.0≤x≤0.1)were prepared ...This work investigated the effect of dysprosium(Dy)ions on the structural,microstructural and magnetic properties of nickel nanospinelferrite,NiFe2 O4.The nanoparticles(NPs)of NiDyxFe(2-x)O4(0.0≤x≤0.1)were prepared via the hydrothermal method.The formation of cubic phase of Ni nanoferrite was confirmed through X-ray diffraction,field emission scanning and transmission electron microscopy.Moreover,the magnetic properties of NiDyxFe(2-x)P4(0.01≤x≤0.10)NPs were discussed.The magnetization versus field,M(H)curves exhibit super paramagnetic nature at room temperature and ferrimagnetic nature at low temperature(10 K).A noticeable improvement in the different deduced magnetic parameters is obtained especially for the NiDy(0.07)Fe(1.93)O4(x=0.07)product.The obtained result is mostly derived from the substitution of Fe^3+ions of smaller ionic radii with Dy^3+ions of larger ionic radii that will strengthen the super exchange interactions among nanoparticles.The calculated squareness ratios are found to be much less than 0.5,due to the effect of spin disorder in the surface regions of NiDyxFe(2-x)O4(0.01≤x≤0.10)NPs.The Dy^3+ions substitution increases the magnetic hardness(higher values of remanence Mr,coercivity Hc,and magnetic moment nB)of nickel nanoferrite samples.展开更多
The elemental chemical state of NiFe2O4@TiO2 was changed by the reduction in order to investigate its effects on the photocatalytic performance.The synthesized NiFe2O4@TiO2 samples were characterized by means of X-ray...The elemental chemical state of NiFe2O4@TiO2 was changed by the reduction in order to investigate its effects on the photocatalytic performance.The synthesized NiFe2O4@TiO2 samples were characterized by means of X-ray diffraction (XRD),high-resolution transmission electron microscopy (HRTEM),Fourier-transform infrared spectroscopy (FT-IR),X-ray photoelectron spectroscopy (XPS),magnetic and photocatalytic measurements.Unexpectedly,the reduction reaction does not produce oxygen vacancies Ov and TiOx in the TiO2 lattice.The optimal catalyst was obtained at the reducing temperature of 800℃,and its degradation efficiency De to the methylene blue and reaction rate constant Kapp are the highest,reaching 99.9% and 3×10^-2 min-1,respectively.The reason could not be explained by both the visible light absorption and the appropriate amount of Ov and TiOx.Instead,the lowest ratios of TiOH and Ti-O-Fe(Ni) may be responsible for the optimum photocatalytic performance.展开更多
The residues of organophosphorus pesticide(OPs)on fruits and vegetables pose a threat to human health,so it is very meaningful to explore simple and fast detect methods for OPs residual.In this work,nickel ferrite/nic...The residues of organophosphorus pesticide(OPs)on fruits and vegetables pose a threat to human health,so it is very meaningful to explore simple and fast detect methods for OPs residual.In this work,nickel ferrite/nickel oxide nanoparticles co-loaded three-dimensional reduced graphene oxide(3DRGONiFe2O4/NiO NPs),as a new low cost nanocomposite,was prepared.Based on its high performance mimetic peroxidase activity,a colorimetric method for the detection of OPs has been developed.Dichlorvos was chosen as model compounds to evaluate the detection performance.The detection linear range for dichlorvos is from 50μg/mL to 2.5×10^4μg/mL with a detection limit of 10μg/mL.Furthermore,a test paper can be developed based on the 3 DRGO-NiFe2O4/NiO NPs for visual detection of dichlorvos,and the image information of the paper sensor can be converted into digital signal and quantitative detection by a smartphone.Notably,this method can also be used to detect dichlorvos in real samples,including vegetables and fruits.Thus,the developed naked assay holds great potential in simple,inexpensive and rapid detection of OPs in fruit and vegetable samples.展开更多
基金supported by the National Natural Science Foundation of China(21573031 and 21428301)the Fundamental Research Funds for the Central Universities(DUT15ZD106)
文摘Spinel ferrites NiFeOsupported Ru catalysts have been prepared via a simple sol–gel route and applied for converting biomass-derived furfural to 2-methylfuran. The as-prepared catalysts were characterized by thermogravimetric analysis（TG）, Nadsorption–desorption, X-ray diffraction（XRD）, scanning electronic microscopy（SEM）, and X-ray photoelectron spectroscopy（XPS）. Results showed that the catalysts had well-dispersed Ru active sites and large surface area for calcination temperature ranging from 300 to 500 ℃. The conversion of biomass-derived furfural into 2-methylfuran was conducted over Ru/NiFeOthrough catalytic transfer hydrogenation in liquid-phase with 2-propanol as the hydrogen source. A significantly enhanced activity and increased 2-methylfuran yield have been achieved in this study. Under mild conditions（180 ℃ and 2.1 MPa N）, the conversion of furfural exceeds 97% and 2-methylfuran yield was up to 83% over the catalyst containing 8 wt% Ru. After five repeated uses, the catalytic activity and the corresponding product yield remained almost unchanged. The excellent catalytic activity and recycling performance provide a broad prospects for various practical applications.
基金financially supported by the National Natural Science Foundation of China (No.11564042)the Precious Metal Materials Genetic Engineering Major Project of Yunnan Province (No.2019ZE001)+1 种基金the Project of the Department of Science and Technology of Yunnan Province (Nos.2018FB091 and 2019FB129)the Project of the Department of Education of Yunnan Province (No.2019J0001)。
文摘The extensive use of toluene stimulates the effective detection by sensitive gas sensors based on unique materials.Here,hierarchical flower-like NiFe_(2)O_(4) with core-shell architecture was synthesized by a facile hydrothermal method in the presence of urea and NH4 F.The controllable experiments indicated that the burr spheres and football-like samples were produced with individual urea or NH4 F.The flower-like NiFe_(2)O_(4) sensor exhibited outstanding sensitivity of 19.95 to 100×10^(-6) toluene with low detection limit(1×10^(-6)).Furthermore,the sensor showed superior sensing selectivity and longterm stability to toluene.The excellent sensing properties could largely arise from a combination of high surface area,numerous active sites,porous structures,and the native catalytic characteristics of NiFe2 O4 to facilitate toluene molecules adsorption,diffusion,and reaction.
文摘This work investigated the effect of dysprosium(Dy)ions on the structural,microstructural and magnetic properties of nickel nanospinelferrite,NiFe2 O4.The nanoparticles(NPs)of NiDyxFe(2-x)O4(0.0≤x≤0.1)were prepared via the hydrothermal method.The formation of cubic phase of Ni nanoferrite was confirmed through X-ray diffraction,field emission scanning and transmission electron microscopy.Moreover,the magnetic properties of NiDyxFe(2-x)P4(0.01≤x≤0.10)NPs were discussed.The magnetization versus field,M(H)curves exhibit super paramagnetic nature at room temperature and ferrimagnetic nature at low temperature(10 K).A noticeable improvement in the different deduced magnetic parameters is obtained especially for the NiDy(0.07)Fe(1.93)O4(x=0.07)product.The obtained result is mostly derived from the substitution of Fe^3+ions of smaller ionic radii with Dy^3+ions of larger ionic radii that will strengthen the super exchange interactions among nanoparticles.The calculated squareness ratios are found to be much less than 0.5,due to the effect of spin disorder in the surface regions of NiDyxFe(2-x)O4(0.01≤x≤0.10)NPs.The Dy^3+ions substitution increases the magnetic hardness(higher values of remanence Mr,coercivity Hc,and magnetic moment nB)of nickel nanoferrite samples.
基金the Open Fund for Discipline Construction,Institute of Physical Science and Information Technology,Anhui Universitythe National Natural Science Foundation of China(No.51471001)。
文摘The elemental chemical state of NiFe2O4@TiO2 was changed by the reduction in order to investigate its effects on the photocatalytic performance.The synthesized NiFe2O4@TiO2 samples were characterized by means of X-ray diffraction (XRD),high-resolution transmission electron microscopy (HRTEM),Fourier-transform infrared spectroscopy (FT-IR),X-ray photoelectron spectroscopy (XPS),magnetic and photocatalytic measurements.Unexpectedly,the reduction reaction does not produce oxygen vacancies Ov and TiOx in the TiO2 lattice.The optimal catalyst was obtained at the reducing temperature of 800℃,and its degradation efficiency De to the methylene blue and reaction rate constant Kapp are the highest,reaching 99.9% and 3×10^-2 min-1,respectively.The reason could not be explained by both the visible light absorption and the appropriate amount of Ov and TiOx.Instead,the lowest ratios of TiOH and Ti-O-Fe(Ni) may be responsible for the optimum photocatalytic performance.
基金financially supported by the National Natural Science Foundation of China (Nos.21874061,21207057,21405159, 21505061)the Fundamental Research Funds for the Central Universities (Nos.lzujbky-2016-43,lzujbky-2018-80)
文摘The residues of organophosphorus pesticide(OPs)on fruits and vegetables pose a threat to human health,so it is very meaningful to explore simple and fast detect methods for OPs residual.In this work,nickel ferrite/nickel oxide nanoparticles co-loaded three-dimensional reduced graphene oxide(3DRGONiFe2O4/NiO NPs),as a new low cost nanocomposite,was prepared.Based on its high performance mimetic peroxidase activity,a colorimetric method for the detection of OPs has been developed.Dichlorvos was chosen as model compounds to evaluate the detection performance.The detection linear range for dichlorvos is from 50μg/mL to 2.5×10^4μg/mL with a detection limit of 10μg/mL.Furthermore,a test paper can be developed based on the 3 DRGO-NiFe2O4/NiO NPs for visual detection of dichlorvos,and the image information of the paper sensor can be converted into digital signal and quantitative detection by a smartphone.Notably,this method can also be used to detect dichlorvos in real samples,including vegetables and fruits.Thus,the developed naked assay holds great potential in simple,inexpensive and rapid detection of OPs in fruit and vegetable samples.
