IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and character...IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.展开更多
This paper investigates the effect of Nb doping on the electronic structure and optical properties of Sr2TiO4 by the first-principles calculation of plane wave ultra-soft pseudo-potential based on density functional t...This paper investigates the effect of Nb doping on the electronic structure and optical properties of Sr2TiO4 by the first-principles calculation of plane wave ultra-soft pseudo-potential based on density functional theory (DFT).The calculated results reveal that due to the electron doping,the Fermi level shifts into conduction bands(CBs) for Sr2NbxTi1-xO4 with x=0.125 and the system shows n-type degenerate semiconductor features. Sr2TiO4 exhibits optical anisotropy in its main crystal axes,and the c-axis shows the most suitable crystal growth direction for obtaining a wide transparent region.The optical transmittance is higher than 90% in the visible range for Sr2Nb0.125Ti0.875O4.展开更多
All-inorganic CsPbBr_(3)-based perovskite solar cells(PSCs)have attracted great attention because of their high chemical and thermal stabilities in ambient air.However,the short-circuit current density(J_(sc))of CsPbB...All-inorganic CsPbBr_(3)-based perovskite solar cells(PSCs)have attracted great attention because of their high chemical and thermal stabilities in ambient air.However,the short-circuit current density(J_(sc))of CsPbBr_(3)-based PSCs is inadequate under solar illumination because of the wide bandgap,inefficient charge extraction and recombination loss,leading to lower power-conversion efficiencies(PCEs).It is envisaged that in addition to narrowing the bandgap by alloying,J_(sc)of the PSCs could be enhanced by effective improvement of electron transportation,suppression of charge recombination at the interface between the perovskite and electron transporting layer(ETL),and tuning of the space charge field in the device.In this work,Nb-doped SnO_(2)films as ETLs in the CsPbBr_(3)-based PSCs have been deposited at room temperature by high target utilization sputtering(Hi TUS).Through optimizing the Nb doping level alone,the J_(sc)was increased by nearly 19%,from 7.51 to 8.92 mA·cm^(-2)and the PCE was enhanced by 27%from 6.73%to 8.54%.The overall benefit by replacing the spin-coated SnO_(2)with sputtered SnO_(2)with Nb doping was up to 39%increase in J_(sc)and 62%increase in PCE.Moreover,the PCE of the optimized device showed negligible degradation over exposure to ambient environment(T~25°C,RH~45%),with 95.4%of the original PCE being maintained after storing the device for 1200 h.展开更多
Spinel (O01)-orientated Mn304 thin films on Nb-doped SrTi03 (001) substrates are fabricated via the pulsed laser deposition method. X-ray diffraction and high-resolution transmission electron microscopy indicate t...Spinel (O01)-orientated Mn304 thin films on Nb-doped SrTi03 (001) substrates are fabricated via the pulsed laser deposition method. X-ray diffraction and high-resolution transmission electron microscopy indicate that the as-prepared epitaxial fihn is well crystaiHzed. In the film plane the orientation relationship between the film and the substrate is [lOOjMn3 04 ||[110] Nb-doped SrTiO3. After an electroforming process, the film shows bipolar nonvolatile resistance switching behavior. The positive voltage bias drives the sample into a low resistance state, while the negative voltage switches it back to a high resistance state. The switching polarity is different from the previous studies. The complex impedance measurement suggests that the resistance switching behavior is of filament type. Due to the performance reproducibility and state stability, Mn3O4 might be a promising candidate for the resistive random access memory devices.展开更多
Nb-doped SrTiO3 (STNO) films were grown on (001)-oriented LaAlO3 substrates by a reactive ion beam sputter deposition at various mixing ratios (OMRs) with a substrate temperature of 800oC. The STNO films exhibited goo...Nb-doped SrTiO3 (STNO) films were grown on (001)-oriented LaAlO3 substrates by a reactive ion beam sputter deposition at various mixing ratios (OMRs) with a substrate temperature of 800oC. The STNO films exhibited good crystallinity with an epitaxial orientation as characterized by high-resolution X-ray diffraction, grazing-incidence X-ray diffraction, and in-plane pole figure analysis. A decrease of out-of-plane and in-plane lattice constants was observed with an increase of OMR. The surface morphology of the STNO films showed a very dense fine-grain structure. The root-mean-square roughness was found to be increased as the OMR increased. Moreover, the elemental compositions of the STNO films were examined by X-ray photoelectron spectroscopy.展开更多
We studied the effects of reductive annealing on insulating polycrystalline thin films of anatase Nb- doped TiO2 (TNO). The insulating TNO films were intentionally fabricated by annealing conductive TNO films in oxy...We studied the effects of reductive annealing on insulating polycrystalline thin films of anatase Nb- doped TiO2 (TNO). The insulating TNO films were intentionally fabricated by annealing conductive TNO films in oxygen ambient at 400 ℃. Reduced free carrier absorption in the insulating TNO films indicated carrier com- pensation due to excess oxygen. With H2-annealing, both carrier density and Hall mobility recovered to the level of conducting TNO, demonstrating that the excess oxygen can be efficiently removed by the annealing process without introducing additional scattering centers.展开更多
Nb-doped TiO2 nanoparticles were prepared by hydrothermal treatment of titanate nanotubes in niobium oxalate aqueous solution.The effect of Nb doping and rutile content on the photoelectrochemical performance based on...Nb-doped TiO2 nanoparticles were prepared by hydrothermal treatment of titanate nanotubes in niobium oxalate aqueous solution.The effect of Nb doping and rutile content on the photoelectrochemical performance based on TiO2 powder electrodes was investigated.The results show that Nb-doped TiO2 with a small amount of rutile exhibits the enhanced photoelectric conversion efficiency for dye-sensitized solar cell.The highest photoelectric conversion efficiency of 8.53%is obtained for 1%Nb—TiO2 containing a small amount of rutile.When a small amount of rutile contained in 2%Nb—TiO2,a higher photoelectric conversion efficiency of8.77%is achieved.展开更多
Nb-doped SrTiO3 thermoelectric ceramics with different niobium concentrations,sintering temperatures and Sr-site vacancies are successfully prepared by high energy ball milling combined with carbon burial sintering.Fo...Nb-doped SrTiO3 thermoelectric ceramics with different niobium concentrations,sintering temperatures and Sr-site vacancies are successfully prepared by high energy ball milling combined with carbon burial sintering.For fully understanding the effect of niobium doping on SrTiO3,thermoelectric transport properties are systematically investigated in a temperature range from 300 K to 1100 K.The carrier mobility can be significantly enhanced,and the electrical conductivity is quadrupled,when the sintering temperature rises from 1673 K to 1773 K(beyond the eutectic temperature(1713 K) of SrTiO3–TiO2).The lattice vibration can be suppressed by the lattice distortion introduced by the doped niobium atoms.However,Sr-site vacancies compensate for the lattice distortion and increase the lattice thermal conductivity more or less.Finally,we achieve a maximum value of figure-of-merit z T of 0.21 at 1100 K for Sr Ti(0.9)Nb(0.1)O3 ceramic sintered at1773 K.展开更多
Nb-doped ZnO thin films were fabricated on glass substrates by using co-sputtering with direct-current and radio frequency magnetron sputtering.The structures,optical and electrical performances of Nb-doped ZnO thin f...Nb-doped ZnO thin films were fabricated on glass substrates by using co-sputtering with direct-current and radio frequency magnetron sputtering.The structures,optical and electrical performances of Nb-doped ZnO thin films were investigated.The results showed that all thin films have(002)c-axis preferential orientation.The minimum resistivity of 2.12×10^(-3)Ωcm and the maximum carrier concentration of 2.39×10^(19 )cm^(-3) were obtained at the direct-current sputtering power of 10W,respectively.Nb-doped ZnO thin films have also shown high average transmittance of 89.6%,and lower surface roughness of 2.74 nm.Meanwhile,a distinct absorption edge in the ultraviolet range of 300–400 nm was observed in absorbance,the optical band gap of Nb-doped ZnO thin films illustrates an increased tendency with increasing Nb concentration.展开更多
Growth temperature effects on the microstructure of Nb-doped BaTiO_(3) thin films of the composition BaTi_(0.98)Nb_(0.02)O_(3) are studied using X-ray diffraction and transmission electron microscopy(TEM).Reciprocal s...Growth temperature effects on the microstructure of Nb-doped BaTiO_(3) thin films of the composition BaTi_(0.98)Nb_(0.02)O_(3) are studied using X-ray diffraction and transmission electron microscopy(TEM).Reciprocal space maps and electron diffraction patterns show that the a-axis lattice parameter increases and the c-axis parameter decreases with increasing growth temperature,indicating a decrease of tetragonality.Bright-field TEM images show low and high densities of threading defects in films grown at low and high temperatures,respectively.The observations are discussed in terms of a hindering of the cubic-to-tetragonal phase transition by a high defect density and a high unit cell volume.展开更多
The activities of protactinium were produced by the multi-nucleontransfer reactions in bombardment of the natural uranium with 60 MeV/nucleon 1sOions. A simple, relatively fast radiochemical procedure was used for ext...The activities of protactinium were produced by the multi-nucleontransfer reactions in bombardment of the natural uranium with 60 MeV/nucleon 1sOions. A simple, relatively fast radiochemical procedure was used for extraction sep-aration of protactinium from the uranium and a variety of reaction products using1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and tri-iso-octylamine as extractants. Theγ ray spectrum of the separated protactinium fractions showed that the protactiniumcould be separated from all of the main impurity elements. The decontaminationfactors of the uranium and the main reaction products produced in the reaction aregiven.展开更多
Ba0.65Sr0.35TiO3 ceramics doped with B2O3-SiO2 glass composition were prepared by using conventional solid-state reaction method. The effects of glass dopant on the dielectric and ferroelectric properties were investi...Ba0.65Sr0.35TiO3 ceramics doped with B2O3-SiO2 glass composition were prepared by using conventional solid-state reaction method. The effects of glass dopant on the dielectric and ferroelectric properties were investigated. The results show that the dielectric constant decreases while the dielectric loss increases after doping. And as the glass content increases the dielectric constant decreases while the dielectric loss changes slightly. From the complex impedance analysis the resistance and the relaxation time of the grain and the grain boundary can be calculated. Comparing the P—E hysteresis loop of undoped Ba0.65Sr0.35TiO3 ceramics with that of B2O3-SiO2 doped Ba0.65Sr0.35TiO3 ceramics, it can be seen that the remanent polarization decreases when the B2O3-SiO2 content is lower than 8%(molar fraction), and the coercive field increases with the increase of B2O3-SiO2 content.展开更多
The development of a high-performance ferroelectric piezo-photocatalyst is an efficient strategy for advancing sustainability within the environmental and energy sectors.Yet,a major challenge lies in the creation of a...The development of a high-performance ferroelectric piezo-photocatalyst is an efficient strategy for advancing sustainability within the environmental and energy sectors.Yet,a major challenge lies in the creation of a strong polarized electric field that can effectively hinder charge recombination,both within the bulk and on the surface of catalysts.Herein,we synthesize a series of Nb-doped Bi_(4)Ti_(3)O_(12)nanosheets via a facile one-pot hydrothermal method to achieve synergistically enhanced piezo-photocatalytic performance in CO_(2)reduction and pollutant degradation.The optimized doped Bi_(4)Ti_(3)O_(12)demonstrates remarkable efficiency in the conversion of CO_(2)into CO,with a high production rate of 72.7μmol∙g−1∙h−1 without using co-catalysts or any sacrificial agent,surpassing the performance of unmodified Bi_(4)Ti_(3)O_(12)by up to 4.69 folds.Additionally,our catalyst demonstrates ultra-fast piezo-photocatalytic degradation of organic pollutant Rhodamine B(RhB)at low concentrations and exceptional piezo-photocatalytic activity at high concentrations,outperforming most previously reported state-of-the-art catalysts.The systematic corroboration of catalyst characterization and experimental analysis reveals that the synergistic effect arises from the amplified macroscopic polarization induced by lattice distortion caused by the larger Nb ions,thereby improving piezo-photocatalytic efficiency.This research thus offers valuable insights into the direct design and fabrication of versatile catalytic systems,with applications spanning CO_(2)valorization and beyond.展开更多
文摘IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.
基金Project supported by the Natural Science Foundation of ShaanXi Province of China (Grant No 2005F06)Northwest University(NWU) Graduate Innovation and Creativity Funds (Grant No 08YZZ47)
文摘This paper investigates the effect of Nb doping on the electronic structure and optical properties of Sr2TiO4 by the first-principles calculation of plane wave ultra-soft pseudo-potential based on density functional theory (DFT).The calculated results reveal that due to the electron doping,the Fermi level shifts into conduction bands(CBs) for Sr2NbxTi1-xO4 with x=0.125 and the system shows n-type degenerate semiconductor features. Sr2TiO4 exhibits optical anisotropy in its main crystal axes,and the c-axis shows the most suitable crystal growth direction for obtaining a wide transparent region.The optical transmittance is higher than 90% in the visible range for Sr2Nb0.125Ti0.875O4.
基金supported by the National Natural Science Foundation of China(Nos.51602290,91233101,11174256)the Fundamental Research Program from the Ministry of Science and Technology of China(No.2014CB31704)+4 种基金Project funded by China Postdoctoral Science Foundation(No.2016M592310)the financial support from EPSRC New Investigator Award(2018EP/R043272/1)H2020-EU grant(2018CORNET 760949)
文摘All-inorganic CsPbBr_(3)-based perovskite solar cells(PSCs)have attracted great attention because of their high chemical and thermal stabilities in ambient air.However,the short-circuit current density(J_(sc))of CsPbBr_(3)-based PSCs is inadequate under solar illumination because of the wide bandgap,inefficient charge extraction and recombination loss,leading to lower power-conversion efficiencies(PCEs).It is envisaged that in addition to narrowing the bandgap by alloying,J_(sc)of the PSCs could be enhanced by effective improvement of electron transportation,suppression of charge recombination at the interface between the perovskite and electron transporting layer(ETL),and tuning of the space charge field in the device.In this work,Nb-doped SnO_(2)films as ETLs in the CsPbBr_(3)-based PSCs have been deposited at room temperature by high target utilization sputtering(Hi TUS).Through optimizing the Nb doping level alone,the J_(sc)was increased by nearly 19%,from 7.51 to 8.92 mA·cm^(-2)and the PCE was enhanced by 27%from 6.73%to 8.54%.The overall benefit by replacing the spin-coated SnO_(2)with sputtered SnO_(2)with Nb doping was up to 39%increase in J_(sc)and 62%increase in PCE.Moreover,the PCE of the optimized device showed negligible degradation over exposure to ambient environment(T~25°C,RH~45%),with 95.4%of the original PCE being maintained after storing the device for 1200 h.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB921904 and 2012CB927402the National Natural Science Foundation of China under Grant Nos 11074142 and 11021464the Key Project of the Ministry of Education of China under Grant No 309003
文摘Spinel (O01)-orientated Mn304 thin films on Nb-doped SrTi03 (001) substrates are fabricated via the pulsed laser deposition method. X-ray diffraction and high-resolution transmission electron microscopy indicate that the as-prepared epitaxial fihn is well crystaiHzed. In the film plane the orientation relationship between the film and the substrate is [lOOjMn3 04 ||[110] Nb-doped SrTiO3. After an electroforming process, the film shows bipolar nonvolatile resistance switching behavior. The positive voltage bias drives the sample into a low resistance state, while the negative voltage switches it back to a high resistance state. The switching polarity is different from the previous studies. The complex impedance measurement suggests that the resistance switching behavior is of filament type. Due to the performance reproducibility and state stability, Mn3O4 might be a promising candidate for the resistive random access memory devices.
文摘Nb-doped SrTiO3 (STNO) films were grown on (001)-oriented LaAlO3 substrates by a reactive ion beam sputter deposition at various mixing ratios (OMRs) with a substrate temperature of 800oC. The STNO films exhibited good crystallinity with an epitaxial orientation as characterized by high-resolution X-ray diffraction, grazing-incidence X-ray diffraction, and in-plane pole figure analysis. A decrease of out-of-plane and in-plane lattice constants was observed with an increase of OMR. The surface morphology of the STNO films showed a very dense fine-grain structure. The root-mean-square roughness was found to be increased as the OMR increased. Moreover, the elemental compositions of the STNO films were examined by X-ray photoelectron spectroscopy.
基金partially supported by JSPS KAKENHI Grant Number 15K04687
文摘We studied the effects of reductive annealing on insulating polycrystalline thin films of anatase Nb- doped TiO2 (TNO). The insulating TNO films were intentionally fabricated by annealing conductive TNO films in oxygen ambient at 400 ℃. Reduced free carrier absorption in the insulating TNO films indicated carrier com- pensation due to excess oxygen. With H2-annealing, both carrier density and Hall mobility recovered to the level of conducting TNO, demonstrating that the excess oxygen can be efficiently removed by the annealing process without introducing additional scattering centers.
基金supported by the National Natural Science Foundation of China(No.51172233)the Major State Basic Research Development Program of China("973 Program",No. 2009CB220002)the Key Laboratory of Water and Air Pollution Control of Guandong Province,China(GD2012A05)
文摘Nb-doped TiO2 nanoparticles were prepared by hydrothermal treatment of titanate nanotubes in niobium oxalate aqueous solution.The effect of Nb doping and rutile content on the photoelectrochemical performance based on TiO2 powder electrodes was investigated.The results show that Nb-doped TiO2 with a small amount of rutile exhibits the enhanced photoelectric conversion efficiency for dye-sensitized solar cell.The highest photoelectric conversion efficiency of 8.53%is obtained for 1%Nb—TiO2 containing a small amount of rutile.When a small amount of rutile contained in 2%Nb—TiO2,a higher photoelectric conversion efficiency of8.77%is achieved.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0403803)the National Natural Science Foundation of China(Grant Nos.51774065,51525401,51690163,and 51601028)the Dalian Support Plan for Innovation of High-level Talents(Top and Leading Talents)(Grant No.2015R013)
文摘Nb-doped SrTiO3 thermoelectric ceramics with different niobium concentrations,sintering temperatures and Sr-site vacancies are successfully prepared by high energy ball milling combined with carbon burial sintering.For fully understanding the effect of niobium doping on SrTiO3,thermoelectric transport properties are systematically investigated in a temperature range from 300 K to 1100 K.The carrier mobility can be significantly enhanced,and the electrical conductivity is quadrupled,when the sintering temperature rises from 1673 K to 1773 K(beyond the eutectic temperature(1713 K) of SrTiO3–TiO2).The lattice vibration can be suppressed by the lattice distortion introduced by the doped niobium atoms.However,Sr-site vacancies compensate for the lattice distortion and increase the lattice thermal conductivity more or less.Finally,we achieve a maximum value of figure-of-merit z T of 0.21 at 1100 K for Sr Ti(0.9)Nb(0.1)O3 ceramic sintered at1773 K.
文摘Nb-doped ZnO thin films were fabricated on glass substrates by using co-sputtering with direct-current and radio frequency magnetron sputtering.The structures,optical and electrical performances of Nb-doped ZnO thin films were investigated.The results showed that all thin films have(002)c-axis preferential orientation.The minimum resistivity of 2.12×10^(-3)Ωcm and the maximum carrier concentration of 2.39×10^(19 )cm^(-3) were obtained at the direct-current sputtering power of 10W,respectively.Nb-doped ZnO thin films have also shown high average transmittance of 89.6%,and lower surface roughness of 2.74 nm.Meanwhile,a distinct absorption edge in the ultraviolet range of 300–400 nm was observed in absorbance,the optical band gap of Nb-doped ZnO thin films illustrates an increased tendency with increasing Nb concentration.
基金supported by the Korea Research Council of Fundamental Science and Technology(KRCF)through a Basic Research Project managed by the Korea Research Institute of Standards and Science(KRISS)Support was also given by the Natural Science Foundation of China(Grant No.61271127).
文摘Growth temperature effects on the microstructure of Nb-doped BaTiO_(3) thin films of the composition BaTi_(0.98)Nb_(0.02)O_(3) are studied using X-ray diffraction and transmission electron microscopy(TEM).Reciprocal space maps and electron diffraction patterns show that the a-axis lattice parameter increases and the c-axis parameter decreases with increasing growth temperature,indicating a decrease of tetragonality.Bright-field TEM images show low and high densities of threading defects in films grown at low and high temperatures,respectively.The observations are discussed in terms of a hindering of the cubic-to-tetragonal phase transition by a high defect density and a high unit cell volume.
基金Supported by the National Natural Science Foundation of China(10075063),and by the Chinese Academy of Sciences(TK95T-03)
文摘The activities of protactinium were produced by the multi-nucleontransfer reactions in bombardment of the natural uranium with 60 MeV/nucleon 1sOions. A simple, relatively fast radiochemical procedure was used for extraction sep-aration of protactinium from the uranium and a variety of reaction products using1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and tri-iso-octylamine as extractants. Theγ ray spectrum of the separated protactinium fractions showed that the protactiniumcould be separated from all of the main impurity elements. The decontaminationfactors of the uranium and the main reaction products produced in the reaction aregiven.
基金Project(50372017/E0204) supported by the National Natural Science Foundation of China
文摘Ba0.65Sr0.35TiO3 ceramics doped with B2O3-SiO2 glass composition were prepared by using conventional solid-state reaction method. The effects of glass dopant on the dielectric and ferroelectric properties were investigated. The results show that the dielectric constant decreases while the dielectric loss increases after doping. And as the glass content increases the dielectric constant decreases while the dielectric loss changes slightly. From the complex impedance analysis the resistance and the relaxation time of the grain and the grain boundary can be calculated. Comparing the P—E hysteresis loop of undoped Ba0.65Sr0.35TiO3 ceramics with that of B2O3-SiO2 doped Ba0.65Sr0.35TiO3 ceramics, it can be seen that the remanent polarization decreases when the B2O3-SiO2 content is lower than 8%(molar fraction), and the coercive field increases with the increase of B2O3-SiO2 content.
基金the Natural Science Foundation of Jiangsu Province(No.BK20220596)Innovative Science and Technology Platform Project of Cooperation between Yangzhou City and Yangzhou University,China(No.YZ202026305)+3 种基金the Natural Science Foundation of China(Nos.21922202 and 21673202)the Priority Academic Program Development of Jiangsu Higher Education Institutions,Shaanxi Province High-level Talent Introduction Program(Youth Project)Doctoral Research Start-up Fund project of Xi’an Polytechnic University(No.107020589)the Biological Resources Development and the Textile Wastewater Treatment Innovation Team(No.23JP055).
文摘The development of a high-performance ferroelectric piezo-photocatalyst is an efficient strategy for advancing sustainability within the environmental and energy sectors.Yet,a major challenge lies in the creation of a strong polarized electric field that can effectively hinder charge recombination,both within the bulk and on the surface of catalysts.Herein,we synthesize a series of Nb-doped Bi_(4)Ti_(3)O_(12)nanosheets via a facile one-pot hydrothermal method to achieve synergistically enhanced piezo-photocatalytic performance in CO_(2)reduction and pollutant degradation.The optimized doped Bi_(4)Ti_(3)O_(12)demonstrates remarkable efficiency in the conversion of CO_(2)into CO,with a high production rate of 72.7μmol∙g−1∙h−1 without using co-catalysts or any sacrificial agent,surpassing the performance of unmodified Bi_(4)Ti_(3)O_(12)by up to 4.69 folds.Additionally,our catalyst demonstrates ultra-fast piezo-photocatalytic degradation of organic pollutant Rhodamine B(RhB)at low concentrations and exceptional piezo-photocatalytic activity at high concentrations,outperforming most previously reported state-of-the-art catalysts.The systematic corroboration of catalyst characterization and experimental analysis reveals that the synergistic effect arises from the amplified macroscopic polarization induced by lattice distortion caused by the larger Nb ions,thereby improving piezo-photocatalytic efficiency.This research thus offers valuable insights into the direct design and fabrication of versatile catalytic systems,with applications spanning CO_(2)valorization and beyond.