The growing demand for luminescent nanomaterials intended for various applications increases the necessity to develop and improve approaches to the creation of highly efficient nanosized phosphors.In current study,an ...The growing demand for luminescent nanomaterials intended for various applications increases the necessity to develop and improve approaches to the creation of highly efficient nanosized phosphors.In current study,an approach to enhancing the efficiency of red luminescence of monoclinic Y_(2)O_(3):Eu^(3+)with the particle size of~20 nm by creating the oxygen-enriched environment during the gas-phase synthesis was developed.To investigate the effect of oxygen amount during the synthesis on characteristics of the phosphor,a series of nano structured Y_(2)O_(3):Eu^(3+)with the addition of 0-40 vol%O_(2) to the main buffer gas Ar was synthesized by laser vaporization.It is shown that the amount of added O_(2) exerts virtually no effect on the phase composition and particle size,but significantly improves the luminescent characteristics of Y_(2)O_(3):Eu^(3+).Thus,the addition of 30 vol%O_(2) leads to virtually a 20-fold growth in the photoluminescence(PL)intensity caused by ^(5)D_(0)→^(7)F_(0-4) transitions in Eu^(3+)and an increase in the absolute PL quantum yield from 3%to 53%(λex=395 nm)compared to the sample synthesized without O_(2).The addition of oxygen also improves the emission color coordinates from(0.571,0.320)to(0.630,0.322)due to the removal of a considerable fraction of oxygen vacancies.The synthesized nanopowders are shown to be highly stable:upon storage under ambient conditions for two years.Quantum yield(QY)of the samples decreases by less than 2%.It is expected that the key features underlying the proposed approach will be useful for various methods used to synthesize oxide nanophosphors.展开更多
Fe-loaded activated carbon(AC)has high surface acidity and more active sites,while manganese-loaded AC has high oxygen content.Coconut husk AC modified by Fe-Mn was studied with the aim of revealing the modification m...Fe-loaded activated carbon(AC)has high surface acidity and more active sites,while manganese-loaded AC has high oxygen content.Coconut husk AC modified by Fe-Mn was studied with the aim of revealing the modification mechanism.First,HNO_(3)AC was prepared using the nitric acid immersion method.Second,Fe-Mn/AC was prepared using the Fe(N0_(3))_(3)and Mn(N0_(3))_(2)sequential immersion.The effects of HNO_(3),Fe(N0_(3))_(3),and Mn(N0_(3))_(2)on the pore texture and surface chemical characteristics of carbon materials were examined by scanning electron microscopy,Brunauer-Emmett-Teller(BET)analysis,X-ray diffraction and Fourier-transform infrared spectroscopy.The surface topography,pore structure,active material,and functional groups of AC,HNO_(3)/AC,and Fe-Mn/AC were systematically studied.The following results were obtained.The surface of HNO_(3)AC has more ditches and air voids;the micropores of HNO_(3)AC are deformed and flattened compared to those of AC.The surface of Fe-Mn/AC exhibits an accumulation phenomenon.MnFe_(2)O_(4)and FeMn_(2)O_(4)formed more pore structures.AC and HNO_(3)AC have numerous micropores.The higher loading quantity of Fe-Mn results in bigger specific surface.The active components of Fe-Mn/AC-1,Fe-Mn/AC-2,Fe-Mn/AC-3,and Fe-Mn/AC-4 are MnFe_(2)O_(4),MnO_(0.43)Fe_(2.57)O_(4),Mn_(3)O_(4),and ot-Fe_(2)O_(3)>respectively.The surface functional groups of AC and HNO_(3)AC are oxygen-containing functional groups.The effect of Fe-Mn modifying conditions on functional group species is rare;however,Fe/AC has more oxygen-containing functional groups.These research findings can aid in the desulfurization and denitrification of the Fe-Mn/AC catalyst.展开更多
Cationic hydrogels have received great attention to control eutrophication and recycle phosphate.In this study,a type of La(OH)_(3) loaded magnetic MAPTAC-based cationic hydrogel(La(OH)_(3)@MMCH)was developed as a pot...Cationic hydrogels have received great attention to control eutrophication and recycle phosphate.In this study,a type of La(OH)_(3) loaded magnetic MAPTAC-based cationic hydrogel(La(OH)_(3)@MMCH)was developed as a potential adsorbent for enhanced phosphate removal from aqueous environment.La(OH)_(3)@MMCH exhibited high adsorption capacity of 105.72±5.99 mg P/g,and reached equilibrium within 2 hr.La(OH)_(3)@MMCH could perform effectively in a wide pH range from 3.0 to 9.0 and in the presence of coexisting ions(including SO_(4)^(2-),Cl^(-),NO_(3)^(-),HCO_(3)^(-),SiO_(4)^(4-) and HA).The adsorption-desorption experiment indicated that La(OH)_(3)@MMCH could be easily regenerated by using NaOH-NaCl as the desorption agent,and 73.3%adsorption capacity remained after five cycles.Moreover,La(OH)_(3)@MMCH was employed to treat surface water with phosphate concentration of 1.90 mg/L and showed great removal efficiency of 95.21%.Actually,MMCH showed high surface charge density of 34.38-59.38 meq/kg in the pH range from 3.0 to 11.0 and great swelling ratio of 3014.57%within 24 h,indicating that MMCH could produce the enhanced Donnan membrane effect to pre-permeate phosphate.Furthermore,the bifunctional structure of La(OH)_(3)@MMCH enabled it to capture phosphate through electrostatic attraction and ligand exchange.All the results prove that La(OH)_(3)@MMCH is a promising adsorbent for eutrophication control and phosphate recovery.展开更多
The dose-dependent cytotoxicity effect on human hepatocyte(HL-7702 cells)induced by"naked"Fe3O4 nanoparticles was assessed through cell viabilities and lactate dehydrogenase(LDH)activities.Three important ox...The dose-dependent cytotoxicity effect on human hepatocyte(HL-7702 cells)induced by"naked"Fe3O4 nanoparticles was assessed through cell viabilities and lactate dehydrogenase(LDH)activities.Three important oxi dative indexes of the cells by glutathione peroxidase(GSH-Px),superoxide dismutase(SOD)and malondialde hyde(MDA)were determined.The good correlation of the cell viabilities with their GSH-Px,SOD and MDA levels indicated that the cytotoxicity is related to activation of oxidative stress induced by Fe3O4 nanoparticles.The oxida tive stress also leads to corresponding DNA damage in a similar dose-dependent manner,followed by the changes of cell cycle and cell apoptosis.Such work provides important experimental data for the safety evaluation of superpa ramagnetic Fe3O4 nanoparticles.展开更多
In this study,Er^(3+)/Yb^(3+)codoped Y_(2)O_(3)-ZnO ceramic phosphors were prepared by sol-gel method.The samples had two emission bands,namely,green(535 nm) and red(660 nm),which are attributed to Er^(3+):^(2)H_(11/2...In this study,Er^(3+)/Yb^(3+)codoped Y_(2)O_(3)-ZnO ceramic phosphors were prepared by sol-gel method.The samples had two emission bands,namely,green(535 nm) and red(660 nm),which are attributed to Er^(3+):^(2)H_(11/2)(^(4)S_(3/2))→^(4)I_(15/2)and Er^(3+):^(4)F_(9/2)→^(4)I_(15/2)radiative transitions,respectively.The samples exhibited green-and red-emission intensity enhancement by 1.728 and 2.286 times that of the pure Y2O3host,respectively and by 514.468 and 214.341 times that of the pure ZnO host.The emission intensities are first enhanced by lattice expansion.With the change of Y:Zn ratio,the high surface energy is converted into low crystal surface resulting in the change of asymmetry crystal field for matrix.When the intensity of the asymmetric crystal field reaches maximum,both emissions are further boosted.When the high surface energy transforms into crystal surface energy,the microstructure changes into a compact mesoporous structure.Consequently,the chemical stability of the samples improves significantly,and the final emission band of the three samples with mesoporous structures is continuously red.展开更多
Using the first-principles methods,the effects of different alloying elements M(M=Fe,Ni,Mn,Si,Mo,Cu,Y)on Cr_(2)0_(3)with Cl adsorption are studied.The results show that the layer distance of all doped models has been ...Using the first-principles methods,the effects of different alloying elements M(M=Fe,Ni,Mn,Si,Mo,Cu,Y)on Cr_(2)0_(3)with Cl adsorption are studied.The results show that the layer distance of all doped models has been widened to different degrees with Cl adsorption.When Mo or Y is doped into the passive film,the difference of layer distance is reduced to a certain extent.The interaction between alloying elements and Cl is studied by calculating the adsorption height,bond population and electron density difference.The results show that Mo and Y can inhibit Cl erosion and improve the corrosion resistance of passive film.Furthermore,we investigate the CrMoFe and CrMoY co-doped system with Cl adsorption.The calculations point out that when Mo and Y are doped together in the passive film,the corrosion resistance of the system is more prominent than that of CrMo,CrY and CrMoFe co-doping systems.展开更多
Modification conditions determine the surface topography and the active material phase composition of a catalyst.To study the influence of modification on a carbon-based sorbent,coconut husk activated carbon(AC)which ...Modification conditions determine the surface topography and the active material phase composition of a catalyst.To study the influence of modification on a carbon-based sorbent,coconut husk activated carbon(AC)which was activated using HNO_(3)and modified by FeSO4 and Fe(NO_(3))_(3)was examined.The pore textures and surface chemical characteristics of the carbon materials were examined by scanning electron microscopy(SEM),Brunner-Emmet-Teller(BET),X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy.The surface topography,the pore structure,active materials,and functional groups of AC,AC modificated by HNO3(HNO3/AC for short),and AC modificated by FeSO4 and Fe(NO3)3(Fe/AC for short)were systematically studied.Subsequently,the mechanism of modifying the conditions for the carbon materials was determined.Results showed that the surface micro topography of HNO3/AC became unsystematic and disordered.After modification with FeSO4,the ferriferous oxide was mainly present as a near-spherical crystal.Ferriferous oxides from Fe(NO_(3))_(3)modification mainly exhibited a plate shape.HNO_(3)modification could enlarge the pores but decrease the specific surface area of AC.FeSO_(4)modification resulted in a new net post structure in the pore canal of AC.Fe(NO_(3))_(3)modification caused the pore space structure to develop in the interior,and a higher calcination temperature was useful for ablation.The ash content of the AC was substantially reduced upon HNO_(3)modification.Upon FeSO_(4)modification,α-FeOOH,α-Fe_(2)O_(3)andγ-Fe_(2)O_(3)coexisted under the condition of a lower concentration of FeSO_(4)and a lower calcination temperature,and a higher FeSO_(4)concentration and calcination temperature generated moreα-Fe_(2)O_(3).The same Fe(NO_(3))_(3)modification and a higher calcination temperature were beneficial to the minor chipping formation ofγ-Fe_(2)O_(3).A higher Fe(NO_(3))_(3)loading produced a lower graphitization degree.HNO_(3)modification formed various new oxygen-containing functional groups and few nitrogen-containing groups.Based on the cover,FeSO_(4)and Fe(NO_(3))_(3)modification could decrease the oxygen-containing and nitrogen-containing functional groups.These results could optimize the modification condition and improve physical and chemical properties of carbon-based sorbents.展开更多
High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Fur...High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Furthermore,the low electrical conductivity combined with a decline in capacity upon prolonged cycling(>1000 cycles)related to the loss of active material-carbon conducting contact regions contributes to moderate rate performance and cycling stability.The need for high specific energy cathodes that meet practical electrochemical requirements has prompted a search for new materials.Herein,we introduce a new carbon-coated Na_(3)VFe_(0.5)Ti_(0.5)(PO_(4))_(3)(NVFTP/C)material as a promising candidate in the NASICON family of cathodes for SIBs.With a high specific energy of∼457 Wh kg^(-1) and a high Na+insertion voltage of 3.0 V versus Na^(+)/Na,this cathode can undergo a reversible single-phase solid-solution and two-phase(de)sodiation evolution at 28 C(1 C=174.7 mAh g^(-1))for up to 10,000 cycles.This study highlights the potential of utilizing low-cost and highly efficient cathodes made from Earth-abundant and harmless materials(Fe and Ti)with enriched Na^(+)-storage properties in practical SIBs.展开更多
通过多步反应制备了一种p H响应性磁性介孔二氧化硅纳米复合粒子Fe_(3)O_(4)/m Si O_(2)/聚(丙烯酸异丁酯-co-丙烯酸)(Fe_(3)O_(4)/m Si O_(2)/P(IBA-co-AA)).纳米复合粒子由包覆介孔二氧化硅的Fe_(3)O_(4)核和聚(丙烯酸异丁酯-co-丙烯...通过多步反应制备了一种p H响应性磁性介孔二氧化硅纳米复合粒子Fe_(3)O_(4)/m Si O_(2)/聚(丙烯酸异丁酯-co-丙烯酸)(Fe_(3)O_(4)/m Si O_(2)/P(IBA-co-AA)).纳米复合粒子由包覆介孔二氧化硅的Fe_(3)O_(4)核和聚(丙烯酸异丁酯-co-丙烯酸)的p H响应性外壳组成.利用红外光谱(FT-IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、振动样品磁强计(VSM)对其结构、物相和性能进行了表征。以抗癌药物阿霉素(DOX)为模型药物,研究了Fe_(3)O_(4)/m Si O_(2)/P(IBA-co-AA)磁性纳米复合粒子在模拟人体环境中的控释行为.选择SMCC7211肝癌细胞为模型细胞,用MTT法研究载药粒子的细胞毒性,并评价载药纳米粒子在细胞中的抗癌效果.结果表明:Fe_(3)O_(4)/m Si O_(2)/P(IBA-co-AA)可作为包载阿霉素的一种新型纳米材料,载药颗粒具有良好的p H响应性,可以有效释放DOX药物来抑制癌细胞的增殖.展开更多
The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient el...The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient electrocatalytic reduction of NO_(3)^(-) to NH_(3)at low concentration.The La-doped Co_(3)O_(4)nanoneedle arrays exhibit remarkable activity with the highest Faradaic efficiency of 95.5%and an ammonia yield rate of 4.08 mg/(h·cm^(2))at-0.3 V versus RHE in 0.02 mol/L NO_(3)^(-).Experiments and theoretical calculations show that the La doping not only facilitates the surface reconstruction to form active La-Co(OH)_(2),but also inhibits the hydrogen evolution reaction over Co sites,thus promoting the NH_(3)production.This work provides new insights into the promoting effect of the rare earth elements in transition metalbased electrocatalyst for nitrate reduction.展开更多
基金Project supported by Russian Science Foundation(22-73-00106)partly by NIIC project(121031700313-8,M.Rakhmanova,PL kinetics study)。
文摘The growing demand for luminescent nanomaterials intended for various applications increases the necessity to develop and improve approaches to the creation of highly efficient nanosized phosphors.In current study,an approach to enhancing the efficiency of red luminescence of monoclinic Y_(2)O_(3):Eu^(3+)with the particle size of~20 nm by creating the oxygen-enriched environment during the gas-phase synthesis was developed.To investigate the effect of oxygen amount during the synthesis on characteristics of the phosphor,a series of nano structured Y_(2)O_(3):Eu^(3+)with the addition of 0-40 vol%O_(2) to the main buffer gas Ar was synthesized by laser vaporization.It is shown that the amount of added O_(2) exerts virtually no effect on the phase composition and particle size,but significantly improves the luminescent characteristics of Y_(2)O_(3):Eu^(3+).Thus,the addition of 30 vol%O_(2) leads to virtually a 20-fold growth in the photoluminescence(PL)intensity caused by ^(5)D_(0)→^(7)F_(0-4) transitions in Eu^(3+)and an increase in the absolute PL quantum yield from 3%to 53%(λex=395 nm)compared to the sample synthesized without O_(2).The addition of oxygen also improves the emission color coordinates from(0.571,0.320)to(0.630,0.322)due to the removal of a considerable fraction of oxygen vacancies.The synthesized nanopowders are shown to be highly stable:upon storage under ambient conditions for two years.Quantum yield(QY)of the samples decreases by less than 2%.It is expected that the key features underlying the proposed approach will be useful for various methods used to synthesize oxide nanophosphors.
基金The authors are grateful for Open Fund of Key Laboratory of Ministry of Education for metallurgical emission reduction and comprehensive utilization of resources(JKF19-08),General Project of Science and Technology Plan of Yunnan Science and Technology Department(2019FB077 and 202001AT070029)the Open Fund of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(Grant No.FMRUlab-20-4).
文摘Fe-loaded activated carbon(AC)has high surface acidity and more active sites,while manganese-loaded AC has high oxygen content.Coconut husk AC modified by Fe-Mn was studied with the aim of revealing the modification mechanism.First,HNO_(3)AC was prepared using the nitric acid immersion method.Second,Fe-Mn/AC was prepared using the Fe(N0_(3))_(3)and Mn(N0_(3))_(2)sequential immersion.The effects of HNO_(3),Fe(N0_(3))_(3),and Mn(N0_(3))_(2)on the pore texture and surface chemical characteristics of carbon materials were examined by scanning electron microscopy,Brunauer-Emmett-Teller(BET)analysis,X-ray diffraction and Fourier-transform infrared spectroscopy.The surface topography,pore structure,active material,and functional groups of AC,HNO_(3)/AC,and Fe-Mn/AC were systematically studied.The following results were obtained.The surface of HNO_(3)AC has more ditches and air voids;the micropores of HNO_(3)AC are deformed and flattened compared to those of AC.The surface of Fe-Mn/AC exhibits an accumulation phenomenon.MnFe_(2)O_(4)and FeMn_(2)O_(4)formed more pore structures.AC and HNO_(3)AC have numerous micropores.The higher loading quantity of Fe-Mn results in bigger specific surface.The active components of Fe-Mn/AC-1,Fe-Mn/AC-2,Fe-Mn/AC-3,and Fe-Mn/AC-4 are MnFe_(2)O_(4),MnO_(0.43)Fe_(2.57)O_(4),Mn_(3)O_(4),and ot-Fe_(2)O_(3)>respectively.The surface functional groups of AC and HNO_(3)AC are oxygen-containing functional groups.The effect of Fe-Mn modifying conditions on functional group species is rare;however,Fe/AC has more oxygen-containing functional groups.These research findings can aid in the desulfurization and denitrification of the Fe-Mn/AC catalyst.
基金This work was supported by the Beijing Municipal Science and Technology Project(No.Z181100005518007)the National Key Research and Development Program of China(No.2017YFC0505303)the National Natural Science Foundation of China(Nos.51978054 and 51678053).
文摘Cationic hydrogels have received great attention to control eutrophication and recycle phosphate.In this study,a type of La(OH)_(3) loaded magnetic MAPTAC-based cationic hydrogel(La(OH)_(3)@MMCH)was developed as a potential adsorbent for enhanced phosphate removal from aqueous environment.La(OH)_(3)@MMCH exhibited high adsorption capacity of 105.72±5.99 mg P/g,and reached equilibrium within 2 hr.La(OH)_(3)@MMCH could perform effectively in a wide pH range from 3.0 to 9.0 and in the presence of coexisting ions(including SO_(4)^(2-),Cl^(-),NO_(3)^(-),HCO_(3)^(-),SiO_(4)^(4-) and HA).The adsorption-desorption experiment indicated that La(OH)_(3)@MMCH could be easily regenerated by using NaOH-NaCl as the desorption agent,and 73.3%adsorption capacity remained after five cycles.Moreover,La(OH)_(3)@MMCH was employed to treat surface water with phosphate concentration of 1.90 mg/L and showed great removal efficiency of 95.21%.Actually,MMCH showed high surface charge density of 34.38-59.38 meq/kg in the pH range from 3.0 to 11.0 and great swelling ratio of 3014.57%within 24 h,indicating that MMCH could produce the enhanced Donnan membrane effect to pre-permeate phosphate.Furthermore,the bifunctional structure of La(OH)_(3)@MMCH enabled it to capture phosphate through electrostatic attraction and ligand exchange.All the results prove that La(OH)_(3)@MMCH is a promising adsorbent for eutrophication control and phosphate recovery.
基金Supported by the National Natural Science Foundation of China(Nos.51072064,50825202)
文摘The dose-dependent cytotoxicity effect on human hepatocyte(HL-7702 cells)induced by"naked"Fe3O4 nanoparticles was assessed through cell viabilities and lactate dehydrogenase(LDH)activities.Three important oxi dative indexes of the cells by glutathione peroxidase(GSH-Px),superoxide dismutase(SOD)and malondialde hyde(MDA)were determined.The good correlation of the cell viabilities with their GSH-Px,SOD and MDA levels indicated that the cytotoxicity is related to activation of oxidative stress induced by Fe3O4 nanoparticles.The oxida tive stress also leads to corresponding DNA damage in a similar dose-dependent manner,followed by the changes of cell cycle and cell apoptosis.Such work provides important experimental data for the safety evaluation of superpa ramagnetic Fe3O4 nanoparticles.
基金Project supported by the National Natural Science Foundation of China (12104117)Guangdong Basic and Applied Basic Research Foundation (2020A1515010432)Characteristic Innovation Project of Guangdong Provincial Universities 2020 (2020KTXCX077)。
文摘In this study,Er^(3+)/Yb^(3+)codoped Y_(2)O_(3)-ZnO ceramic phosphors were prepared by sol-gel method.The samples had two emission bands,namely,green(535 nm) and red(660 nm),which are attributed to Er^(3+):^(2)H_(11/2)(^(4)S_(3/2))→^(4)I_(15/2)and Er^(3+):^(4)F_(9/2)→^(4)I_(15/2)radiative transitions,respectively.The samples exhibited green-and red-emission intensity enhancement by 1.728 and 2.286 times that of the pure Y2O3host,respectively and by 514.468 and 214.341 times that of the pure ZnO host.The emission intensities are first enhanced by lattice expansion.With the change of Y:Zn ratio,the high surface energy is converted into low crystal surface resulting in the change of asymmetry crystal field for matrix.When the intensity of the asymmetric crystal field reaches maximum,both emissions are further boosted.When the high surface energy transforms into crystal surface energy,the microstructure changes into a compact mesoporous structure.Consequently,the chemical stability of the samples improves significantly,and the final emission band of the three samples with mesoporous structures is continuously red.
基金This research is supported by the National Natural Science Foundation of China(Grant Nos.U1860204 and 51871159)the Natural Science Foundation of Shanxi Province(Grant No.201801D221125)Shanxi Engineering Technology Research Center for Energy Materials&Analysis and Testing.
文摘Using the first-principles methods,the effects of different alloying elements M(M=Fe,Ni,Mn,Si,Mo,Cu,Y)on Cr_(2)0_(3)with Cl adsorption are studied.The results show that the layer distance of all doped models has been widened to different degrees with Cl adsorption.When Mo or Y is doped into the passive film,the difference of layer distance is reduced to a certain extent.The interaction between alloying elements and Cl is studied by calculating the adsorption height,bond population and electron density difference.The results show that Mo and Y can inhibit Cl erosion and improve the corrosion resistance of passive film.Furthermore,we investigate the CrMoFe and CrMoY co-doped system with Cl adsorption.The calculations point out that when Mo and Y are doped together in the passive film,the corrosion resistance of the system is more prominent than that of CrMo,CrY and CrMoFe co-doping systems.
基金General Project of Science and Technology Plan of Yunnan Science and Technology Department,China(No.2019FB077)Open Fund of Key Laboratory of Ministry of Education for Metallurgical Emission Reduction and Comprehensive Utilization of Resources,China(No.JKF19-08)。
文摘Modification conditions determine the surface topography and the active material phase composition of a catalyst.To study the influence of modification on a carbon-based sorbent,coconut husk activated carbon(AC)which was activated using HNO_(3)and modified by FeSO4 and Fe(NO_(3))_(3)was examined.The pore textures and surface chemical characteristics of the carbon materials were examined by scanning electron microscopy(SEM),Brunner-Emmet-Teller(BET),X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy.The surface topography,the pore structure,active materials,and functional groups of AC,AC modificated by HNO3(HNO3/AC for short),and AC modificated by FeSO4 and Fe(NO3)3(Fe/AC for short)were systematically studied.Subsequently,the mechanism of modifying the conditions for the carbon materials was determined.Results showed that the surface micro topography of HNO3/AC became unsystematic and disordered.After modification with FeSO4,the ferriferous oxide was mainly present as a near-spherical crystal.Ferriferous oxides from Fe(NO_(3))_(3)modification mainly exhibited a plate shape.HNO_(3)modification could enlarge the pores but decrease the specific surface area of AC.FeSO_(4)modification resulted in a new net post structure in the pore canal of AC.Fe(NO_(3))_(3)modification caused the pore space structure to develop in the interior,and a higher calcination temperature was useful for ablation.The ash content of the AC was substantially reduced upon HNO_(3)modification.Upon FeSO_(4)modification,α-FeOOH,α-Fe_(2)O_(3)andγ-Fe_(2)O_(3)coexisted under the condition of a lower concentration of FeSO_(4)and a lower calcination temperature,and a higher FeSO_(4)concentration and calcination temperature generated moreα-Fe_(2)O_(3).The same Fe(NO_(3))_(3)modification and a higher calcination temperature were beneficial to the minor chipping formation ofγ-Fe_(2)O_(3).A higher Fe(NO_(3))_(3)loading produced a lower graphitization degree.HNO_(3)modification formed various new oxygen-containing functional groups and few nitrogen-containing groups.Based on the cover,FeSO_(4)and Fe(NO_(3))_(3)modification could decrease the oxygen-containing and nitrogen-containing functional groups.These results could optimize the modification condition and improve physical and chemical properties of carbon-based sorbents.
基金This work was supported by the National Research Foundation of Korea(NRF)Grant funded by the Korean government(MSIT)(NRF-2018R1A5A1025224 and NRF-2021R1A4A1052051)This work was also supported by the National Research Foundation of Korea Grant funded by the Korean Government Ministry of Education and Science Technology(NRF-2021R1I1A3060193).
文摘High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Furthermore,the low electrical conductivity combined with a decline in capacity upon prolonged cycling(>1000 cycles)related to the loss of active material-carbon conducting contact regions contributes to moderate rate performance and cycling stability.The need for high specific energy cathodes that meet practical electrochemical requirements has prompted a search for new materials.Herein,we introduce a new carbon-coated Na_(3)VFe_(0.5)Ti_(0.5)(PO_(4))_(3)(NVFTP/C)material as a promising candidate in the NASICON family of cathodes for SIBs.With a high specific energy of∼457 Wh kg^(-1) and a high Na+insertion voltage of 3.0 V versus Na^(+)/Na,this cathode can undergo a reversible single-phase solid-solution and two-phase(de)sodiation evolution at 28 C(1 C=174.7 mAh g^(-1))for up to 10,000 cycles.This study highlights the potential of utilizing low-cost and highly efficient cathodes made from Earth-abundant and harmless materials(Fe and Ti)with enriched Na^(+)-storage properties in practical SIBs.
文摘通过多步反应制备了一种p H响应性磁性介孔二氧化硅纳米复合粒子Fe_(3)O_(4)/m Si O_(2)/聚(丙烯酸异丁酯-co-丙烯酸)(Fe_(3)O_(4)/m Si O_(2)/P(IBA-co-AA)).纳米复合粒子由包覆介孔二氧化硅的Fe_(3)O_(4)核和聚(丙烯酸异丁酯-co-丙烯酸)的p H响应性外壳组成.利用红外光谱(FT-IR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、振动样品磁强计(VSM)对其结构、物相和性能进行了表征。以抗癌药物阿霉素(DOX)为模型药物,研究了Fe_(3)O_(4)/m Si O_(2)/P(IBA-co-AA)磁性纳米复合粒子在模拟人体环境中的控释行为.选择SMCC7211肝癌细胞为模型细胞,用MTT法研究载药粒子的细胞毒性,并评价载药纳米粒子在细胞中的抗癌效果.结果表明:Fe_(3)O_(4)/m Si O_(2)/P(IBA-co-AA)可作为包载阿霉素的一种新型纳米材料,载药颗粒具有良好的p H响应性,可以有效释放DOX药物来抑制癌细胞的增殖.
基金Project supported by the National Natural Science Foundation of China(21971129,21961022,21661023)the Inner Mongolia Autonomous Region 2022 Leading Talent Team of Science and Technology(2022LJRC0008)+5 种基金the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2022MS02014,2021BS02007)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(NJYT23031)the 111 Project(D20033)the"Grassland Leading Talent"Program of Inner Mongoliathe"Grassland-Talent"Innovation Team of Inner Mongoliathe"Science and Technology for A Better Development of Inner Mongolia"Program(2020XM03)。
文摘The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient electrocatalytic reduction of NO_(3)^(-) to NH_(3)at low concentration.The La-doped Co_(3)O_(4)nanoneedle arrays exhibit remarkable activity with the highest Faradaic efficiency of 95.5%and an ammonia yield rate of 4.08 mg/(h·cm^(2))at-0.3 V versus RHE in 0.02 mol/L NO_(3)^(-).Experiments and theoretical calculations show that the La doping not only facilitates the surface reconstruction to form active La-Co(OH)_(2),but also inhibits the hydrogen evolution reaction over Co sites,thus promoting the NH_(3)production.This work provides new insights into the promoting effect of the rare earth elements in transition metalbased electrocatalyst for nitrate reduction.
