With a series of 1.0 wt%Bi_(2)O_(3)-x wt%CuO(x=0.0,0.2,0.4,0.6,and 0.8)serving as sintering additives,Ni_(0.23)Cu_(0.32)Zn_(0.45)Ee_(2)O_(4)ferrites are successfully synthesized at a low temperature(900℃)by using the...With a series of 1.0 wt%Bi_(2)O_(3)-x wt%CuO(x=0.0,0.2,0.4,0.6,and 0.8)serving as sintering additives,Ni_(0.23)Cu_(0.32)Zn_(0.45)Ee_(2)O_(4)ferrites are successfully synthesized at a low temperature(900℃)by using the solid state reaction method.The effects of the additives on the phase formation,magnetic and dielectric properties as well as the structural and gyromagnetic properties are investigated.The x-ray diffraction(XRD)results indicate that the added Bi_(2)O_(3)-CuO can lower the synthesis temperature significantly without the appearing of the second phase.The scanning electron microscope(SEM)images confirm that Bi_(2)O_(3)is an important factor that determines the sintering behaviors,while CuO affects the grain size and densification.With CuO content x=0.4 or 0.6,the sample shows high saturation magnetization,low coercivity,high real part of magnetic permeability,dielectric permittivity,and small ferromagnetic resonance linewidth(ΔH).The NiCuZn ferrites are a promising new generation of high-performance microwave devices,such as phase shifters and isolators.展开更多
The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The resu...The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.展开更多
Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-dop...Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.展开更多
The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specro...The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specrometer) and so on. Computer pattern recognition is applied to optimize the heat-treatment schedules. The experimental results show that the base glass containing more than 1 .5 % (mass fraction) Cr2O3 can be nucleated internally and converted to spheroidal crystal glass materials. The spheroidal crystal consisted of fibrous wollastonite crystals radiating from a center. The residual glass phase filled in the interstices between the fibers and between the spherulites. During heat treatment process, the valence states ofchromium changed from Cr6- to Cr3-, and the Cr-spinel solidsolution [CaCr2O4] precipitated followed this valence change. At the primary stage of crystallization, the Cr-spinel could act as a nucleating center on which the principal or}stalline phase β-CaSiO3 grew epitaxially.展开更多
It is interesting to explore a novel oxyfluoride glass with good glass stability to be applied in optical communication and optical windows at infrared(IR)wavelength.We demonstrated a new glass of Ga_(2)O_(3)-doped Zr...It is interesting to explore a novel oxyfluoride glass with good glass stability to be applied in optical communication and optical windows at infrared(IR)wavelength.We demonstrated a new glass of Ga_(2)O_(3)-doped ZrF_(4)-BaF_(2)-LaF_(3)-AlF_(3)-NaF(ZBLAN)glass using a melt-quenched technique.The effect of Ga_(2)O_(3)-doping on glass properties and structure was characterized by differential thermal analysis(DTA),IR spectra,Raman spectra,and X-ray diffraction(XRD).It is found that the glass thermal stability(ΔT)increases by 14% when the addition of Ga_(2)O_(3) reaches 1mol%.With the increase of Ga_(2)O_(3) content,the density and refractive index of the glasses increase.Ga_(2)O_(3)-doping does not affect the IR cut-off edge and maintains the transmittance near 90% in the range of 2.5-5μm,which is almost equal to the undoped sample.Ga_(2)O_(3)-doping hardly changes the initial coordinated structure of Zr^(4+)according to the results of IR spectra and Raman spectra.Ga^(3+)holds in the interstice site of the network coordinated with F^(-)and the part of O_(2)-introduced by Ga_(2)O_(3) is coordinated with Al^(3+)forming Al-O bond.This study offers a new glass composition that may be potentially used in fabricating mid-IR optical fiber and large-size glasses for IR windows.展开更多
The effect of substitution La_(2)O_(3)and YF_(3)as network modifiers respectively for Y_(2)O_(3),and ZnO as intermediate oxide for Al_(2)O_(3)on crystallization and viscous behavior of Y_(2)O_(3)-Al_(2)O_(3)-SiO_(2)gl...The effect of substitution La_(2)O_(3)and YF_(3)as network modifiers respectively for Y_(2)O_(3),and ZnO as intermediate oxide for Al_(2)O_(3)on crystallization and viscous behavior of Y_(2)O_(3)-Al_(2)O_(3)-SiO_(2)glass was studied.La_(2)O_(3)and YF_(3)substitution for Y_(2)O_(3)decreases the melting temperature of studied glass from 1402 to 1346 and 1379℃,and the activation energy of viscous flow decreases from 340 to 250 and 265 kJ/mol.Meanwhile,ZnO substitution for Al_(2)O_(3)decreases the melting temperature to 1379℃while increases the activation energy of viscous flow to 542 kJ/mol,due to their different role in glass structure.Substitution ZnO for Al_(2)O_(3)refines and homogenizes the crystals size and lowers crystallinity because the nucleation and crystal growth are depressed by higher activation energy of crystallization and change of crystallization mechanism from bulk crystallization to surface crystallization.Replacement of Y_(2)O_(3)by La_(2)O_(3)and YF_(3)respectively also decreases the crystallinity of Y_(2)O_(3)-Al_(2)O_(3)-SiO_(2)glass ceramic due to competitive and hindering effect on the rearranged atoms,structural units and groups required by precipitated two crystals.Besides,y-Y2Si2O7,precipitation of Y4.67(SiO4)3O,ZnAl_(2)O_(4),and Y3Si3O10F were observed respectively due to incorporation of La_(2)O_(3),ZnO,and YF_(3).展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFE0115500)the National Natural Science Foundation of China(Grant Nos.52003256 and 51902037)the Natural Science Foundation of Shanxi Province,China(Grant No.201901D211259)。
文摘With a series of 1.0 wt%Bi_(2)O_(3)-x wt%CuO(x=0.0,0.2,0.4,0.6,and 0.8)serving as sintering additives,Ni_(0.23)Cu_(0.32)Zn_(0.45)Ee_(2)O_(4)ferrites are successfully synthesized at a low temperature(900℃)by using the solid state reaction method.The effects of the additives on the phase formation,magnetic and dielectric properties as well as the structural and gyromagnetic properties are investigated.The x-ray diffraction(XRD)results indicate that the added Bi_(2)O_(3)-CuO can lower the synthesis temperature significantly without the appearing of the second phase.The scanning electron microscope(SEM)images confirm that Bi_(2)O_(3)is an important factor that determines the sintering behaviors,while CuO affects the grain size and densification.With CuO content x=0.4 or 0.6,the sample shows high saturation magnetization,low coercivity,high real part of magnetic permeability,dielectric permittivity,and small ferromagnetic resonance linewidth(ΔH).The NiCuZn ferrites are a promising new generation of high-performance microwave devices,such as phase shifters and isolators.
文摘The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.
基金financially supported by the National Natural Science Foundation of China (22005097)the State Key Laboratory of Physical Chemistry of Solid Surfaces,Xiamen University,Xiamen 361005,P.R.China (201815)。
文摘Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.
文摘The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specrometer) and so on. Computer pattern recognition is applied to optimize the heat-treatment schedules. The experimental results show that the base glass containing more than 1 .5 % (mass fraction) Cr2O3 can be nucleated internally and converted to spheroidal crystal glass materials. The spheroidal crystal consisted of fibrous wollastonite crystals radiating from a center. The residual glass phase filled in the interstices between the fibers and between the spherulites. During heat treatment process, the valence states ofchromium changed from Cr6- to Cr3-, and the Cr-spinel solidsolution [CaCr2O4] precipitated followed this valence change. At the primary stage of crystallization, the Cr-spinel could act as a nucleating center on which the principal or}stalline phase β-CaSiO3 grew epitaxially.
基金Funded by the Natural Science Foundation of Shanghai(No.19YF1453300)the National Natural Science Foundation of China(Nos.52072122,51872092,and 52002385)。
文摘It is interesting to explore a novel oxyfluoride glass with good glass stability to be applied in optical communication and optical windows at infrared(IR)wavelength.We demonstrated a new glass of Ga_(2)O_(3)-doped ZrF_(4)-BaF_(2)-LaF_(3)-AlF_(3)-NaF(ZBLAN)glass using a melt-quenched technique.The effect of Ga_(2)O_(3)-doping on glass properties and structure was characterized by differential thermal analysis(DTA),IR spectra,Raman spectra,and X-ray diffraction(XRD).It is found that the glass thermal stability(ΔT)increases by 14% when the addition of Ga_(2)O_(3) reaches 1mol%.With the increase of Ga_(2)O_(3) content,the density and refractive index of the glasses increase.Ga_(2)O_(3)-doping does not affect the IR cut-off edge and maintains the transmittance near 90% in the range of 2.5-5μm,which is almost equal to the undoped sample.Ga_(2)O_(3)-doping hardly changes the initial coordinated structure of Zr^(4+)according to the results of IR spectra and Raman spectra.Ga^(3+)holds in the interstice site of the network coordinated with F^(-)and the part of O_(2)-introduced by Ga_(2)O_(3) is coordinated with Al^(3+)forming Al-O bond.This study offers a new glass composition that may be potentially used in fabricating mid-IR optical fiber and large-size glasses for IR windows.
基金the National Natural Science Foundation of China(No.51974168)the Science and Technology Major Project of Inner Mongolia Autonomous Region in China(Nos.2019ZD023 and 2021ZD0028)the State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)(No.SYSJJ2020-08)。
文摘The effect of substitution La_(2)O_(3)and YF_(3)as network modifiers respectively for Y_(2)O_(3),and ZnO as intermediate oxide for Al_(2)O_(3)on crystallization and viscous behavior of Y_(2)O_(3)-Al_(2)O_(3)-SiO_(2)glass was studied.La_(2)O_(3)and YF_(3)substitution for Y_(2)O_(3)decreases the melting temperature of studied glass from 1402 to 1346 and 1379℃,and the activation energy of viscous flow decreases from 340 to 250 and 265 kJ/mol.Meanwhile,ZnO substitution for Al_(2)O_(3)decreases the melting temperature to 1379℃while increases the activation energy of viscous flow to 542 kJ/mol,due to their different role in glass structure.Substitution ZnO for Al_(2)O_(3)refines and homogenizes the crystals size and lowers crystallinity because the nucleation and crystal growth are depressed by higher activation energy of crystallization and change of crystallization mechanism from bulk crystallization to surface crystallization.Replacement of Y_(2)O_(3)by La_(2)O_(3)and YF_(3)respectively also decreases the crystallinity of Y_(2)O_(3)-Al_(2)O_(3)-SiO_(2)glass ceramic due to competitive and hindering effect on the rearranged atoms,structural units and groups required by precipitated two crystals.Besides,y-Y2Si2O7,precipitation of Y4.67(SiO4)3O,ZnAl_(2)O_(4),and Y3Si3O10F were observed respectively due to incorporation of La_(2)O_(3),ZnO,and YF_(3).
