Transition metals have garnered significant attention for their roles in addressing energy shortages and environmental water pollution.Their multivalent states and unique electron transfer properties facilitate charge...Transition metals have garnered significant attention for their roles in addressing energy shortages and environmental water pollution.Their multivalent states and unique electron transfer properties facilitate charge transfer in the conversion reaction,expedite energy conversion,and achieve low-energy water treatment.This review comprehensively explores the fundamental mechanisms and practical applications of transition metals in water treatment,including adsorption,photocatalysis,electrocatalysis,photoelectrocatalysis,and other technologies.The feasibility of water treatment using transition metal-based materials is demonstrated through theoretical studies on typical transition metals employed in these water treatment technologies while emphasizing the potential for optimizing material performance through strategies like structural design,defect engineering,crystal engineering,composite materials,surface modification,and atomic catalysts.In addition,the utilization of transition metal-based materials in practical wastewater treatment is comprehensively reviewed.Finally,the challenges and perspectives of transition metal-based materials in practical wastewater treatment are outlined,providing a theoretical foundation and guidance for future research and engineering advancements.展开更多
Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study...Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.展开更多
Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,...Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.展开更多
Cryogenic magnetic cooling based on the principle of the magnetocaloric effects(MCEs)of magnetic solids has been recognized as an alternative cooling technology due to its significant economic and social benefits.Desi...Cryogenic magnetic cooling based on the principle of the magnetocaloric effects(MCEs)of magnetic solids has been recognized as an alternative cooling technology due to its significant economic and social benefits.Designing novel magnetic materials with good magnetocaloric performance is a prerequisite for practical applications.In this study,three gadolinium-transition metal-based high entropy oxides(HEOs)of Gd(Fe_(1/4)Ni_(1/4)Al_(1/4)Cr_(1/4))O_(3),Gd(Fe_(1/5)Ni_(1/5)Al_(1/5)Cr_(1/5)Co_(1/5))O_(3),and Gd(Fe_(1/6)Ni_(1/6)Al_(1/6)Cr_(1/6)Co_(1/6)Mn_(1/6))O_(3)were designed and systematically characterized regarding their structural and cryogenic magnetic properties.These HEOs were confirmed to crystallize into a single-phase perovskite-type orthorhombic structure with a homogeneous microstructure,reveal a second-order magnetic transition at low temperatures,and exhibit significant cryogenic MCEs.The magnetocaloric performances of the present HEOs,identified by magnetic entropy changes,relative cooling power,and temperature-averaged entropy changes,were com-parable with recently reported candidate materials.The present study indicates potential applications for cryogenic magnetic cooling of the present HEOs and provides meaningful clues for designing and exploring HEOs with good cryogenic magnetocaloric performances.展开更多
Different transition metals were used to modify V2O5-based catalysts （M-V, M = Cu, Fe, Mn, Co） on TiO2 via impregnation, for the selective reduction of NO with NH3. The introduced metals induced high dispersion in t...Different transition metals were used to modify V2O5-based catalysts （M-V, M = Cu, Fe, Mn, Co） on TiO2 via impregnation, for the selective reduction of NO with NH3. The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO2 showed the highest activity and N2 selectivity at 225-375 ~C. The results of X-ray photo- electron spectroscopy, NH3-temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO2/H2O durability of Cu-V/TiO2 make it a candidate to be a NOx removal catalyst for stationary flue gas.展开更多
Lithium–sulfur(Li–S) batteries have received widespread attention, and lean electrolyte Li–S batteries have attracted additional interest because of their higher energy densities. This review systematically analyze...Lithium–sulfur(Li–S) batteries have received widespread attention, and lean electrolyte Li–S batteries have attracted additional interest because of their higher energy densities. This review systematically analyzes the effect of the electrolyte-to-sulfur(E/S) ratios on battery energy density and the challenges for sulfur reduction reactions(SRR) under lean electrolyte conditions. Accordingly, we review the use of various polar transition metal sulfur hosts as corresponding solutions to facilitate SRR kinetics at low E/S ratios(< 10 μL mg~(-1)), and the strengths and limitations of different transition metal compounds are presented and discussed from a fundamental perspective. Subsequently, three promising strategies for sulfur hosts that act as anchors and catalysts are proposed to boost lean electrolyte Li–S battery performance. Finally, an outlook is provided to guide future research on high energy density Li–S batteries.展开更多
Mg2+in MgAl-layered double hydroxides nanoparticles was substituted with different divalent transition metal ions(MAl-LDHs,M:Mg2+,Cu2+,Ni2+,Co2+,and Mn2+)via a facile method to be used as antibacterial agents.The phas...Mg2+in MgAl-layered double hydroxides nanoparticles was substituted with different divalent transition metal ions(MAl-LDHs,M:Mg2+,Cu2+,Ni2+,Co2+,and Mn2+)via a facile method to be used as antibacterial agents.The phase structural and morphological characterizations of MAl-LDHs were investigated by XRD,FTIR spectroscopy and TEM.The results have shown that all of MAl-LDHs had typical layered structures except MnAl-LDH which contained Mn304 phases.Particular morphology of MnAl-LDH with ellipsoids,spherical and rod-like structure and CuAl-LDH with rod-like shape existed.IC50(the concentrations providing 50%antibacterial activity)values of CuAl-LDH,NiAl-LDH,CoAl-LDH,and MnAlLDH in broth dilution tests were^800-1500μg/mL.Dosages of CuAl-LDH,CoAl-LDH,and MnAl-LDH with>10 mm inhibition zone in disk diffusion tests were^150-300μg/disk.Antibacterial mechanism of MAl-LDHs may be attributed to the synergistic factors including effected surroundings,surface interactions,morphology of particles,ROS and metal ions.The results indicate a facile method to synthesis LDHs based effective antibacterial agents with the potential application in the area of water treatment and antibacterial coating.展开更多
The use of solid state carbothermic reduction as a precursor to the smelting of transition metal ores was examined . The advantages of the introduction of a prereduction stage include enabling the more efficient use o...The use of solid state carbothermic reduction as a precursor to the smelting of transition metal ores was examined . The advantages of the introduction of a prereduction stage include enabling the more efficient use of fines and the achievement of higher energy efficiencies. A solid state reduction using carbon as the reductant offers a simpler alternative for their treatment. Subsequent treatment of the reduced material could include intensive bath smelting to produce ferroalloys or, in some case, solid state separation of the transition metal carbide where this has commercial significance.展开更多
Ambient particulate matter(PM)can cause adverse health effects via their ability to produce Reactive Oxygen Species(ROS).Water-Soluble Organic Compounds(WSOCs),a complex mixture of organic compounds which usually coex...Ambient particulate matter(PM)can cause adverse health effects via their ability to produce Reactive Oxygen Species(ROS).Water-Soluble Organic Compounds(WSOCs),a complex mixture of organic compounds which usually coexist with Transition Metals(TMs)in PM,have been found to contribute to ROS formation.However,the interaction between WSOCs and TMs and its effect on ROS generation are still unknown.In this study,we examined the ROS concentrations of V,Zn,Suwannee River Fulvic Acid(SRFA),Suwannee River Humic Acid(SRHA)and the mixtures of V/Zn and SRFA/SRHA by using a cell-free 2’,7’-Dichlorodihydrofluorescein(DCFH)assay.The results showed that V or Zn synergistically promoted ROS generated by SRFA,but had an antagonistic effect on ROS generated by SRHA.Fluorescence quenching experiments indicated that V and Zn were more prone to form stable complexes with aromatic humic acid-like component(C1)and fulvic acidlike component(C3)in SRFA and SRHA.Results suggested that the underlying mechanism involving the fulvic acid-like component in SRFA more tending to complex with TMs to facilitate ROS generation throughπelectron transfer.Our work showed that the complexing ability and complexing stability of atmospheric PM organics with metals could significantly affect ROS generation.It is recommended that the research deploying multiple analytical methods to quantify the impact of PM components on public health and environment is needed in the future.展开更多
The doping effects of transition metals(TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide(Li,Fe)OHFe Se. The samples are grown via a matrix-assisted hy...The doping effects of transition metals(TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide(Li,Fe)OHFe Se. The samples are grown via a matrix-assisted hydrothermal epitaxy method. Among the TMs, the elements of Mn and Co adjacent to Fe are observed to be incorporated into the crystal lattice more easily. It is suggested that the doped TMs mainly occupy the iron sites of the intercalated(Li,Fe)OH layers rather than those of the superconducting Fe Se layers. We find that the critical current density J_(c) can be enhanced much more strongly by the Mn dopant than the other TMs, while the critical temperature T_(c) is weakly affected by the TM doping.展开更多
The influence of transition metals(Sc,Ti,V,Cr,and Mn)doping at different distances on the magnetism of CdS is studied by using generalized gradient approximation combined with Hubbard U in the VASP package.The results...The influence of transition metals(Sc,Ti,V,Cr,and Mn)doping at different distances on the magnetism of CdS is studied by using generalized gradient approximation combined with Hubbard U in the VASP package.The results show that the doping systems are more stable,easy to form,and the wurtzite structure of CdS is not changed.It is found that the systems are antiferromagnetic(AFM)when nearest neighbor doping,which is attributed to the direct charge transfers between two impurity ions.The systems are ferromagnetic(FM)when the doping distance increases further,since the double exchange interactions are observed among the 3d orbital of the transition metal,the Cd-5s and the S-3p orbitals are at conduction band minimum.We also found that the total magnetic moment of each ferromagnetic system increases with the order of SC to Mn-doping,the spin polarizability of Cr-doping system is 100%.The estimated Curie temperature indicates that the Cr-and Mn-doped CdS in this paper can achieve room-temperature ferromagnetic characteristics,especially the Cr doping is the most prominent.And TM-doping does not destroy the semiconductor characteristics of the system.Therefore,the TM-doped CdS can be used as an ideal dilute magnetic semiconductor functional material.展开更多
Since the correspondence between the impurity and its energy levels within the bands is not exactly known, it is difficult to assign the impurity according to its levels. In this work, several metallic impurities were...Since the correspondence between the impurity and its energy levels within the bands is not exactly known, it is difficult to assign the impurity according to its levels. In this work, several metallic impurities were intentionally doped into samples, then their energy levels were determined by DLTS.展开更多
The catalytic activity of Perovskite-type mixed oxides (LaCoO3, PrCoO3 and SmCoO3) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-PonndorfVerley reduction) has been studied. The data have...The catalytic activity of Perovskite-type mixed oxides (LaCoO3, PrCoO3 and SmCoO3) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-PonndorfVerley reduction) has been studied. The data have been correlated with the surface electron donor properties of these mixed oxides展开更多
A systematic ab initio study on magnetism of the 3d transition metals（TM） from atom to monoatomic wire within density functional theory with generalized gradient approximation（GGA） was performed.The results show t...A systematic ab initio study on magnetism of the 3d transition metals（TM） from atom to monoatomic wire within density functional theory with generalized gradient approximation（GGA） was performed.The results show that the spin coupling has strong intraatomic exchange strengths about 1 eV for isolated 3d TM atoms.The magnetic moments are distinctly lower than those of free atoms for all dimers except Mn 2 .All the 3d TM elements exhibit magnetic ground states in the linear wire structure.展开更多
In the present article, we report the screening-dependent study of the superconducting state parameters （SSPs）, viz. electron-phonon coupling strength A, Coulomb pseudopotential μ^＊, transition temperature TC, iso...In the present article, we report the screening-dependent study of the superconducting state parameters （SSPs）, viz. electron-phonon coupling strength A, Coulomb pseudopotential μ^＊, transition temperature TC, isotope effect exponent a, and effective interaction strength No V of 3d-band transition metals binary alloys superconductors have been made extensively in the present work using a model potential formalism and employing the pseudo-alloy-atom （PAA） model for the first time. Five local field correction functions proposed by Hartree （H）, Taylor （T）, Ichimaru-Utsumi （IU）, Farid et al. （F） and Sarkar et al. （S） are used in the present investigation to study the screening influence on the aforesaid properties. The present results of the SSPs obtained from H-screening are found in qualitative agreement with the available experimental data wherever exist.展开更多
The computer molecular simulation technique was applied to study the chemisorption of thiophene and tetramethylthiophene as the model sulfides on the simple oxides and complex oxides of some transition metals as the c...The computer molecular simulation technique was applied to study the chemisorption of thiophene and tetramethylthiophene as the model sulfides on the simple oxides and complex oxides of some transition metals as the catalytic materials. The study disclosed that the thiophene sulfides could enter into chemisorption with metal oxides such as VO, ZnO, NiO and Zn-Al-spinel. This interaction could lead to thiophene molecular structure deformation to be in an activated adsorption state, which could help to promote the conversion of thiophene sulfides in the course of catalytic cracking. The VO with a valence of 2 could provide relatively strong selective adsorption sites for the conversion of thiophene sulfides to apparently transform the molecular structures and electron cloud states of such heterocyclic sulfur compounds such as thiophene and tetramethylthiophene into an activated adsorption state. The effect of this interaction was more pronounced with respect to tetramethylthiophene.展开更多
An electronic approach to the mechanism of hydrogen embrittlement in metals is pre-sented and discussed. Some problems of the mechanism of hydrogen embrittlement are pointed out from an electronic point of view. Elect...An electronic approach to the mechanism of hydrogen embrittlement in metals is pre-sented and discussed. Some problems of the mechanism of hydrogen embrittlement are pointed out from an electronic point of view. Electronic structure calculations in a periodically cleaved or slipped lattice are developed in orker to identofy deformation-sensitive electronic states in the absence of hydrogen. The calculational results are given and discussed for a trunsition metal, Pd. Electronic structure calculations in the presence of hydrogen are outlined and hydrogen embrittlement in transition metals is discussed in terms of electronic states.展开更多
Five new solid complexes were synthesized about transition metals with Schiff base（ L, C18H23NO2 ） derived from adamantaneamine and o-vanillin, and characterized by elemental analysis, molar conductance, infrared sp...Five new solid complexes were synthesized about transition metals with Schiff base（ L, C18H23NO2 ） derived from adamantaneamine and o-vanillin, and characterized by elemental analysis, molar conductance, infrared spectra, UV-vis spectra, thermal analysis. Their chemical formula are [ML2]（ClO4）2 （ M= Mn, Co, Ni, Cu, Zn）, and the coordination numbers are four, The antibacterial activity of Schiff base ligand and its complexes was studied.展开更多
Searching anodes with excellent electrochemical performance has been in great demand for rechargeable metal ion batteries. In this contribution, Fe/Co co-doped Ni S with N-based carbon(Fe Co-NiS@NC) derived from trime...Searching anodes with excellent electrochemical performance has been in great demand for rechargeable metal ion batteries. In this contribution, Fe/Co co-doped Ni S with N-based carbon(Fe Co-NiS@NC) derived from trimetallic Prussian blue analogue is designed and synthesized. The composition can be easily adjusted and modulated by multi-metals. In addition, the well-designed carbon nanocubes effectively promote electronic conductivity and buffer the volume change upon charge and discharge cycling, resulting in good capacity and long-term cycle life for both lithium-ion batteries and sodium-ion batteries, with capacities of 1018 m Ah g^(-1)(vs. Li/Li^(+)) and 454 m Ah g^(-1)(vs. Na/Na^(+)), respectively, after 100 cycles.Kinetics studies indicate that the electrochemical behaviors are manipulated by both diffusion and pseudocapacitance processes. These strategies would open new opportunities and potention for novel energy storage.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22306026 and 52371346)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2023QNRC001)+3 种基金the Ecological Society of China(No.STQT2023C07)the Fundamental Research Funds for the Central Universities(Nos.2242024K40007 and 2242024RCB0058)the Start-up Research Fund of Southeast University(No.RF1028623141)Tang Scholar Program of Southeast University
文摘Transition metals have garnered significant attention for their roles in addressing energy shortages and environmental water pollution.Their multivalent states and unique electron transfer properties facilitate charge transfer in the conversion reaction,expedite energy conversion,and achieve low-energy water treatment.This review comprehensively explores the fundamental mechanisms and practical applications of transition metals in water treatment,including adsorption,photocatalysis,electrocatalysis,photoelectrocatalysis,and other technologies.The feasibility of water treatment using transition metal-based materials is demonstrated through theoretical studies on typical transition metals employed in these water treatment technologies while emphasizing the potential for optimizing material performance through strategies like structural design,defect engineering,crystal engineering,composite materials,surface modification,and atomic catalysts.In addition,the utilization of transition metal-based materials in practical wastewater treatment is comprehensively reviewed.Finally,the challenges and perspectives of transition metal-based materials in practical wastewater treatment are outlined,providing a theoretical foundation and guidance for future research and engineering advancements.
基金supported by the Weiqiao-UCAS Special Projects on Low-Carbon Technology Development(No.GYY-DTFZ-2022-007)the Fundamental Research Funds for the Central Universities(No.E0E48927×2)the National Natural Science Foundation of China(No.21677145).
文摘Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.
基金supported by the National Key Research and Development Program of China(No.2022YFB3505301)the National Key Research and Development Program of Shanxi Province(No.202302050201014)+2 种基金the National Natural Science Foundation of China(No.12304148)the Natural Science Basic Research Program of Shanxi Province(No.202203021222219)the China Postdoctoral Science Foundation(No.2023M731452).
文摘Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.
基金supported by the National Natural Science Foundation of China(No.52171174).The authors acknowledge Dr.Chao Zhang from the Instrumentation Service Center for Physical Sciences at Westlake University for magnetization measurements.
文摘Cryogenic magnetic cooling based on the principle of the magnetocaloric effects(MCEs)of magnetic solids has been recognized as an alternative cooling technology due to its significant economic and social benefits.Designing novel magnetic materials with good magnetocaloric performance is a prerequisite for practical applications.In this study,three gadolinium-transition metal-based high entropy oxides(HEOs)of Gd(Fe_(1/4)Ni_(1/4)Al_(1/4)Cr_(1/4))O_(3),Gd(Fe_(1/5)Ni_(1/5)Al_(1/5)Cr_(1/5)Co_(1/5))O_(3),and Gd(Fe_(1/6)Ni_(1/6)Al_(1/6)Cr_(1/6)Co_(1/6)Mn_(1/6))O_(3)were designed and systematically characterized regarding their structural and cryogenic magnetic properties.These HEOs were confirmed to crystallize into a single-phase perovskite-type orthorhombic structure with a homogeneous microstructure,reveal a second-order magnetic transition at low temperatures,and exhibit significant cryogenic MCEs.The magnetocaloric performances of the present HEOs,identified by magnetic entropy changes,relative cooling power,and temperature-averaged entropy changes,were com-parable with recently reported candidate materials.The present study indicates potential applications for cryogenic magnetic cooling of the present HEOs and provides meaningful clues for designing and exploring HEOs with good cryogenic magnetocaloric performances.
基金supported by the National Natural Science Foundation of China (21303099)the National Basic Research Program of China(973 Program,2014CB660803)+1 种基金the Shanghai Municipal Education Commission(14ZZ097, B.3704713001)the Research Fund for Innovation Program of Shanghai University (K.10040713003)~~
文摘Different transition metals were used to modify V2O5-based catalysts （M-V, M = Cu, Fe, Mn, Co） on TiO2 via impregnation, for the selective reduction of NO with NH3. The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO2 showed the highest activity and N2 selectivity at 225-375 ~C. The results of X-ray photo- electron spectroscopy, NH3-temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO2/H2O durability of Cu-V/TiO2 make it a candidate to be a NOx removal catalyst for stationary flue gas.
基金the Research Foundation-Flanders (FWO) for a Research Project (G0B3218N)the financial support by the National Natural Science Foundation of China (22005054)+3 种基金Natural Science Foundation of Fujian Province (2021J01149)State Key Laboratory of Structural Chemistry (20200007)Sichuan Science and Technology Program (project No.: 2022ZYD0016 and 2023JDRC0013)the National Natural Science Foundation of China (project No. 21776120)。
文摘Lithium–sulfur(Li–S) batteries have received widespread attention, and lean electrolyte Li–S batteries have attracted additional interest because of their higher energy densities. This review systematically analyzes the effect of the electrolyte-to-sulfur(E/S) ratios on battery energy density and the challenges for sulfur reduction reactions(SRR) under lean electrolyte conditions. Accordingly, we review the use of various polar transition metal sulfur hosts as corresponding solutions to facilitate SRR kinetics at low E/S ratios(< 10 μL mg~(-1)), and the strengths and limitations of different transition metal compounds are presented and discussed from a fundamental perspective. Subsequently, three promising strategies for sulfur hosts that act as anchors and catalysts are proposed to boost lean electrolyte Li–S battery performance. Finally, an outlook is provided to guide future research on high energy density Li–S batteries.
基金financially supported by Advance Queensland Research Fellowship Project and Chinese Scholarship Council(CSC)。
文摘Mg2+in MgAl-layered double hydroxides nanoparticles was substituted with different divalent transition metal ions(MAl-LDHs,M:Mg2+,Cu2+,Ni2+,Co2+,and Mn2+)via a facile method to be used as antibacterial agents.The phase structural and morphological characterizations of MAl-LDHs were investigated by XRD,FTIR spectroscopy and TEM.The results have shown that all of MAl-LDHs had typical layered structures except MnAl-LDH which contained Mn304 phases.Particular morphology of MnAl-LDH with ellipsoids,spherical and rod-like structure and CuAl-LDH with rod-like shape existed.IC50(the concentrations providing 50%antibacterial activity)values of CuAl-LDH,NiAl-LDH,CoAl-LDH,and MnAlLDH in broth dilution tests were^800-1500μg/mL.Dosages of CuAl-LDH,CoAl-LDH,and MnAl-LDH with>10 mm inhibition zone in disk diffusion tests were^150-300μg/disk.Antibacterial mechanism of MAl-LDHs may be attributed to the synergistic factors including effected surroundings,surface interactions,morphology of particles,ROS and metal ions.The results indicate a facile method to synthesis LDHs based effective antibacterial agents with the potential application in the area of water treatment and antibacterial coating.
文摘The use of solid state carbothermic reduction as a precursor to the smelting of transition metal ores was examined . The advantages of the introduction of a prereduction stage include enabling the more efficient use of fines and the achievement of higher energy efficiencies. A solid state reduction using carbon as the reductant offers a simpler alternative for their treatment. Subsequent treatment of the reduced material could include intensive bath smelting to produce ferroalloys or, in some case, solid state separation of the transition metal carbide where this has commercial significance.
基金supported by the Fundamental Research Funds for the Central Universities (No. E0E48927X2)the National Natural Science Foundation of China (No. 21677145)
文摘Ambient particulate matter(PM)can cause adverse health effects via their ability to produce Reactive Oxygen Species(ROS).Water-Soluble Organic Compounds(WSOCs),a complex mixture of organic compounds which usually coexist with Transition Metals(TMs)in PM,have been found to contribute to ROS formation.However,the interaction between WSOCs and TMs and its effect on ROS generation are still unknown.In this study,we examined the ROS concentrations of V,Zn,Suwannee River Fulvic Acid(SRFA),Suwannee River Humic Acid(SRHA)and the mixtures of V/Zn and SRFA/SRHA by using a cell-free 2’,7’-Dichlorodihydrofluorescein(DCFH)assay.The results showed that V or Zn synergistically promoted ROS generated by SRFA,but had an antagonistic effect on ROS generated by SRHA.Fluorescence quenching experiments indicated that V and Zn were more prone to form stable complexes with aromatic humic acid-like component(C1)and fulvic acidlike component(C3)in SRFA and SRHA.Results suggested that the underlying mechanism involving the fulvic acid-like component in SRFA more tending to complex with TMs to facilitate ROS generation throughπelectron transfer.Our work showed that the complexing ability and complexing stability of atmospheric PM organics with metals could significantly affect ROS generation.It is recommended that the research deploying multiple analytical methods to quantify the impact of PM components on public health and environment is needed in the future.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0303003 and 2016YFA0300300)the National Natural Science Foundation of China(Grant Nos.11834016 and 11888101)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB33010200 and XDB25000000)the Strategic Priority Research Program and Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant Nos.QYZDY-SSW-SLH001 and QYZDY-SSW-SLH008)。
文摘The doping effects of transition metals(TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide(Li,Fe)OHFe Se. The samples are grown via a matrix-assisted hydrothermal epitaxy method. Among the TMs, the elements of Mn and Co adjacent to Fe are observed to be incorporated into the crystal lattice more easily. It is suggested that the doped TMs mainly occupy the iron sites of the intercalated(Li,Fe)OH layers rather than those of the superconducting Fe Se layers. We find that the critical current density J_(c) can be enhanced much more strongly by the Mn dopant than the other TMs, while the critical temperature T_(c) is weakly affected by the TM doping.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11664023)the Hong Liu First-class Disciplines Development Program of Lanzhou University of TechnologyState Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals of China
文摘The influence of transition metals(Sc,Ti,V,Cr,and Mn)doping at different distances on the magnetism of CdS is studied by using generalized gradient approximation combined with Hubbard U in the VASP package.The results show that the doping systems are more stable,easy to form,and the wurtzite structure of CdS is not changed.It is found that the systems are antiferromagnetic(AFM)when nearest neighbor doping,which is attributed to the direct charge transfers between two impurity ions.The systems are ferromagnetic(FM)when the doping distance increases further,since the double exchange interactions are observed among the 3d orbital of the transition metal,the Cd-5s and the S-3p orbitals are at conduction band minimum.We also found that the total magnetic moment of each ferromagnetic system increases with the order of SC to Mn-doping,the spin polarizability of Cr-doping system is 100%.The estimated Curie temperature indicates that the Cr-and Mn-doped CdS in this paper can achieve room-temperature ferromagnetic characteristics,especially the Cr doping is the most prominent.And TM-doping does not destroy the semiconductor characteristics of the system.Therefore,the TM-doped CdS can be used as an ideal dilute magnetic semiconductor functional material.
文摘Since the correspondence between the impurity and its energy levels within the bands is not exactly known, it is difficult to assign the impurity according to its levels. In this work, several metallic impurities were intentionally doped into samples, then their energy levels were determined by DLTS.
文摘The catalytic activity of Perovskite-type mixed oxides (LaCoO3, PrCoO3 and SmCoO3) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-PonndorfVerley reduction) has been studied. The data have been correlated with the surface electron donor properties of these mixed oxides
基金supported by the National Natural Science Foundation of China (Grant No.10774132)
文摘A systematic ab initio study on magnetism of the 3d transition metals（TM） from atom to monoatomic wire within density functional theory with generalized gradient approximation（GGA） was performed.The results show that the spin coupling has strong intraatomic exchange strengths about 1 eV for isolated 3d TM atoms.The magnetic moments are distinctly lower than those of free atoms for all dimers except Mn 2 .All the 3d TM elements exhibit magnetic ground states in the linear wire structure.
文摘In the present article, we report the screening-dependent study of the superconducting state parameters （SSPs）, viz. electron-phonon coupling strength A, Coulomb pseudopotential μ^＊, transition temperature TC, isotope effect exponent a, and effective interaction strength No V of 3d-band transition metals binary alloys superconductors have been made extensively in the present work using a model potential formalism and employing the pseudo-alloy-atom （PAA） model for the first time. Five local field correction functions proposed by Hartree （H）, Taylor （T）, Ichimaru-Utsumi （IU）, Farid et al. （F） and Sarkar et al. （S） are used in the present investigation to study the screening influence on the aforesaid properties. The present results of the SSPs obtained from H-screening are found in qualitative agreement with the available experimental data wherever exist.
文摘The computer molecular simulation technique was applied to study the chemisorption of thiophene and tetramethylthiophene as the model sulfides on the simple oxides and complex oxides of some transition metals as the catalytic materials. The study disclosed that the thiophene sulfides could enter into chemisorption with metal oxides such as VO, ZnO, NiO and Zn-Al-spinel. This interaction could lead to thiophene molecular structure deformation to be in an activated adsorption state, which could help to promote the conversion of thiophene sulfides in the course of catalytic cracking. The VO with a valence of 2 could provide relatively strong selective adsorption sites for the conversion of thiophene sulfides to apparently transform the molecular structures and electron cloud states of such heterocyclic sulfur compounds such as thiophene and tetramethylthiophene into an activated adsorption state. The effect of this interaction was more pronounced with respect to tetramethylthiophene.
文摘An electronic approach to the mechanism of hydrogen embrittlement in metals is pre-sented and discussed. Some problems of the mechanism of hydrogen embrittlement are pointed out from an electronic point of view. Electronic structure calculations in a periodically cleaved or slipped lattice are developed in orker to identofy deformation-sensitive electronic states in the absence of hydrogen. The calculational results are given and discussed for a trunsition metal, Pd. Electronic structure calculations in the presence of hydrogen are outlined and hydrogen embrittlement in transition metals is discussed in terms of electronic states.
文摘Five new solid complexes were synthesized about transition metals with Schiff base（ L, C18H23NO2 ） derived from adamantaneamine and o-vanillin, and characterized by elemental analysis, molar conductance, infrared spectra, UV-vis spectra, thermal analysis. Their chemical formula are [ML2]（ClO4）2 （ M= Mn, Co, Ni, Cu, Zn）, and the coordination numbers are four, The antibacterial activity of Schiff base ligand and its complexes was studied.
基金supported by the National Natural Science Foundation of China(Grant Nos.21974007 and 22090043)。
文摘Searching anodes with excellent electrochemical performance has been in great demand for rechargeable metal ion batteries. In this contribution, Fe/Co co-doped Ni S with N-based carbon(Fe Co-NiS@NC) derived from trimetallic Prussian blue analogue is designed and synthesized. The composition can be easily adjusted and modulated by multi-metals. In addition, the well-designed carbon nanocubes effectively promote electronic conductivity and buffer the volume change upon charge and discharge cycling, resulting in good capacity and long-term cycle life for both lithium-ion batteries and sodium-ion batteries, with capacities of 1018 m Ah g^(-1)(vs. Li/Li^(+)) and 454 m Ah g^(-1)(vs. Na/Na^(+)), respectively, after 100 cycles.Kinetics studies indicate that the electrochemical behaviors are manipulated by both diffusion and pseudocapacitance processes. These strategies would open new opportunities and potention for novel energy storage.
