The combined reagents of sodium N-oleoylsarcosinate(SNOS)with metal ions(Ca(Ⅱ),Mg(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ))was employed to facilitate the separation of lepidolite from feldspar.The synergistic interaction mechanism of t...The combined reagents of sodium N-oleoylsarcosinate(SNOS)with metal ions(Ca(Ⅱ),Mg(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ))was employed to facilitate the separation of lepidolite from feldspar.The synergistic interaction mechanism of this combined reagent was systematically investigated via contact angle measurements,AFM,FTIR,species distribution calculations,and DFT calculations.The results suggested that Ca(Ⅱ)exhibited the best selectivity for activating lepidolite flotation.SNOS was chemically adsorbed on the Ca(Ⅱ)-activated lepidolite surface with an adsorption energy of−1248.91 kJ/mol while a lower adsorption energy of−598.84 kJ/mol of SNOS on Ca(Ⅱ)-activated feldspar was calculated.Therefore,this combination of SNOS and Ca(Ⅱ)is a promising reagent scheme for the efficient recovery of lithium from aluminosilicate ore.展开更多
The use of visible-light responsive photocatalysts for removing heavy metal ions in wastewater has received great attention.However,the development of photocatalysts with high activity and recyclability remains a huge...The use of visible-light responsive photocatalysts for removing heavy metal ions in wastewater has received great attention.However,the development of photocatalysts with high activity and recyclability remains a huge challenge.Herein,a recyclable carbon fiber cloth-supported porous CdS nanorod photocatalyst was fabricated by a two-step hydrothermal treatment using AgVO_(3) nanowires as templates.The results indicated that under visible-light illumination,the carbon cloth-supported porous CdS nanorods showed improved photocatalytic activity for the reduction of Cr(Ⅵ),with an apparent rate constant exceeding that of carbon cloth-supported CdS nanospheres by a factor of 1.65 times.Moreover,the carbon cloth-supported porous CdS nanorods can be easily separated and be reused.This brings a new perspective for developing photocatalysts with high efficiency and recyclability for wastewater treatment.展开更多
A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with ...A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.展开更多
This study aims to clarify the mechanisms for the grain boundary(GB)segregation through investigating the absorption of excess solute atoms at GBs in Al−Cu alloys by using the hybrid molecular dynamics/Monte Carlo sim...This study aims to clarify the mechanisms for the grain boundary(GB)segregation through investigating the absorption of excess solute atoms at GBs in Al−Cu alloys by using the hybrid molecular dynamics/Monte Carlo simulations.Two segregation mechanisms,substitutional and interstitial mechanisms,are observed.The intergranular defects,including dislocations,steps and vacancies,and the intervals in structural units are conductive to the prevalence of interstitial mechanism.And substitutional mechanism is favored by the highly ordered twin GBs.Furthermore,the two mechanisms affect the GB structure differently.It is quantified that interstitial mechanism is less destructive to GB structure than substitutional one,and often leads to a segregation level being up to about 6 times higher than the latter.These findings contribute to atomic scale insights into the microscopic mechanisms about how solute atoms are absorbed by GB structures,and clarify the correlation among intergranular structures,segregation mechanisms and kinetics.展开更多
Microstructural evolution and dynamic recrystallization(DRX)mechanisms of a Ti-48Al-2Cr-2Nb(at.%)alloy prepared by selective electron beam melting(SEBM)during hot deformation at 1150℃and 0.1 s^(-1)were investigated b...Microstructural evolution and dynamic recrystallization(DRX)mechanisms of a Ti-48Al-2Cr-2Nb(at.%)alloy prepared by selective electron beam melting(SEBM)during hot deformation at 1150℃and 0.1 s^(-1)were investigated by hot compression tests,optical microscope(OM),scanning electron microscope(SEM),electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results show that the initial microstructure of the as-SEBMed alloy exhibits layers of coarseγgrains and fineγ+α_(2)+(α_(2)/γ)lamellar mixture grains alternately along the building direction.During the early stage of hot deformation,deformation twins tend to form within the coarse grains,facilitating subsequent deformation,and a small number of DRX grains appear in the fine-grained regions.With the increase of strain,extensive DRX grains are formed through different DRX mechanisms in both coarse and fine-grained regions,involving discontinuous dynamic recrystallization mechanism(DDRX)in the fine-grained regions and a coexistence of DDRX and continuous dynamic recrystallization(CDRX)in the coarsegrained regions.展开更多
Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles...Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles of different forms of atomically-dispersed metals(i.e.,single-atoms and atomic clusters)in photocatalytic reactions remain ambiguous.Herein,we developed an ethylenediamine(EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms(Au_(SA)),Au clusters(Au_(C)),and a mixed-phase of Au_(SA)and Au_(C)(Au_(SA+C))on CdS.In addition,we elucidate the synergistic effect of Au_(SA)and Au_(C)in enhancing the photocatalytic performance of CdS substrates for simultaneous CO_(2)reduction and aryl alcohol oxidation.Specifically,Au_(SA)can effectively lower the energy barrier for the CO_(2)→*COOH conversion,while Au_(C)can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation.As a result,the Au_(SA)and Au_(C)co-loaded CdS show impressive overall photocatalytic CO_(2)conversion performance,achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g^(−1)h^(−1),with the selectivities of 93%and 99%,respectively.More importantly,the solar-to-chemical conversion efficiency of Au_(SA+C)/CdS reaches 0.57%,which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature(ca.0.1%).This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions,which is anticipated to pave a new avenue in energy and environmental applications.展开更多
Developing highly active alloy catalysts that surpass the performance of platinum group metals in the oxygen reduction reaction(ORR)is critical in electrocatalysis.Gold-based single-atom alloy(AuSAA)clusters are gaini...Developing highly active alloy catalysts that surpass the performance of platinum group metals in the oxygen reduction reaction(ORR)is critical in electrocatalysis.Gold-based single-atom alloy(AuSAA)clusters are gaining recognition as promising alternatives due to their potential for high activity.However,enhancing its activity of AuSAA clusters remains challenging due to limited insights into its actual active site in alkaline environments.Herein,we studied a variety of Au_(54)M_(1) SAA cluster catalysts and revealed the operando formed MO_(x)(OH)_(y) complex acts as the crucial active site for catalyzing the ORR under the basic solution condition.The observed volcano plot indicates that Au_(54)Co_(1),Au_(54)M_(1),and Au_(54)Ru_(1) clusters can be the optimal Au_(54)M_(1) SAA cluster catalysts for the ORR.Our findings offer new insights into the actual active sites of AuSAA cluster catalysts,which will inform rational catalyst design in experimental settings.展开更多
The bimetallic nanostructures that mix a plasmonic metal with a transition metal in the form of the core-shell nanoparticles are promising to promote catalytic performance.But it is still unclear how the heat(hot elec...The bimetallic nanostructures that mix a plasmonic metal with a transition metal in the form of the core-shell nanoparticles are promising to promote catalytic performance.But it is still unclear how the heat(hot electrons and phonons)transfers on the interface between two metals.We have designed and synthesized Au@Cu bimetallic nanoparticles with Au as core and Cu as shell.By using transient absorption spectroscopy,we find that there are two plasmon induced heat funneling processes from Au core to Cu shell.One is the electron temperature equilibrium(electron heat transfer)with equilibration time of~560 fs.The other is the lattice temperature equilibrium(lattice heat transfer)with equilibration time of~13 ps.This plasmon induced heat funneling may be universal in similar bimetallic nanostructures,so our finding could contribute to further understanding the catalytic mechanism of bimetallic plasmonic photothermal catalysis.展开更多
Metal⁃organic framework(MOF)MIL⁃101 and surface plasmon polariton(SPP)supported gold nanoparti⁃cles(Au NPs)hybrid systems were developed as a highly sensitive and reproducible surface⁃enhanced Raman scat⁃tering(SERS)d...Metal⁃organic framework(MOF)MIL⁃101 and surface plasmon polariton(SPP)supported gold nanoparti⁃cles(Au NPs)hybrid systems were developed as a highly sensitive and reproducible surface⁃enhanced Raman scat⁃tering(SERS)detection platform,in which a green electrostatic self⁃assembly technology was adopted to construct the substrate.In an aqueous solution,the electronegativity of the particles can be used to prepare the composite sub⁃strate without any surface modifier.Due to the enrichment capacity of MIL⁃101 and the electromagnetic enhance⁃ment from Au NPs,the well⁃designed MIL⁃101/Au composites possessed ultrahigh sensitivity with the detection limit of Rhodamine 6G(R6G)as low as 10^(-10) mol·L^(-1).Meanwhile,the substrate exhibits high stability,excellent reproduc⁃ibility,and recyclability.Additionally,the novel substrate can be explored for direct capture,and sensitively detect pesticide residues such as thiram.展开更多
The quest for sustainable energy storage solutions is more critical than ever,with the rise in global energy demand and the urgency of transition from fossil fuels to renewable sources.Carbon nanotubes(CNTs),with thei...The quest for sustainable energy storage solutions is more critical than ever,with the rise in global energy demand and the urgency of transition from fossil fuels to renewable sources.Carbon nanotubes(CNTs),with their exceptional electrical conduct-ivity and structural integrity,are at the forefront of this endeavor,offering promising ways for the advance of electrochemical energy storage(EES)devices.This review provides an analysis of the synthesis,properties,and applications of CNTs in the context of EES.We explore the evolution of CNT synthesis methods,including arc discharge,laser ablation,and chemical vapor deposition,and highlight the recent developments in metal-organic framework-derived CNTs and a novel CNT aggregate with a three-dimensional ordered macroporous structure.We also examine the role of CNTs in improving the performance of various EES devices such as lith-ium-ion,lithium-metal,lithium-sulfur,sodium,and flexible batteries as well as supercapacitors.We underscore the challenges that remain,including the scalability of CNT synthesis and the integration of CNTs in electrode materials,and propose potential solu-tions and future research directions.The review presents a forward-looking perspective on the pivotal role of CNTs in shaping the fu-ture of sustainable EES technologies.展开更多
Thispaper has investigated the coordination and supramolecular assemblies of alkali metal ions,cucurbit[5]uril(Q[5]),and[CdCl_(4)]^(2-)to confirm whether[CdCl_(4)]^(2-)can produce the“honeycomb effect”,induce coordi...Thispaper has investigated the coordination and supramolecular assemblies of alkali metal ions,cucurbit[5]uril(Q[5]),and[CdCl_(4)]^(2-)to confirm whether[CdCl_(4)]^(2-)can produce the“honeycomb effect”,induce coordination of alkali metal ions to Q[5],and form linear coordination polymers.In this work,the effect of alkali metal ions on the construction of Q[5]-Cd^(2+)ion system under acidic conditions was investigated.Five complexes were successfully obtained by solvent evaporation method.Among the five crystal structures obtained,it can be observed that the presence of[CdCl_(4)]^(2-)did not result in the complexation of alkali metal ions by the Q[5]molecule.Instead,a bowl-like Cd^(2+)@Q[5]complex was formed.Indeed,[CdCl_(4)]^(2-)did not produce the honeycomb effect but led to the formation of Q[5]-based honeycomb frameworks with hexagonal cellsoccupied by[CdCl_(4)]^(2-).The experimental results show that cadmium ion showed stronger ability to coordinate to Q[5]in HCl solution.展开更多
Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile...Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.展开更多
Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o ...Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.展开更多
The electrochemical behavior of Al(Ⅲ)in urea-1-butyl-3-methylimidazolium chloride-aluminum chloride(urea-BMIC-AlCl_(3))ionic liquids,and the effect of potential and temperature on the characterization of cathode prod...The electrochemical behavior of Al(Ⅲ)in urea-1-butyl-3-methylimidazolium chloride-aluminum chloride(urea-BMIC-AlCl_(3))ionic liquids,and the effect of potential and temperature on the characterization of cathode products,current efficiency and energy consumption of aluminum electrorefining have been investigated.Cyclic voltammetry showed that the electrochemical reduction of Al(Ⅲ)was a one-step three-electron-transfer irreversible reaction,and the electrochemical reaction was controlled by diffusion.The diffusion coefficient of Al(Ⅲ)in urea-BMIC-AlCl_(3)ionic liquids at 313 K was 1.94×10^(−7)cm^(2)/s.The 7075 aluminum alloy was used as an anode for electrorefining,and the cathode products were analyzed by XRD,SEM and EDS.The results from XRD analysis indicated that the main phase of the cathode products was aluminum.The results from SEM and EDS characterization revealed that the cathode product obtained by electrorefining−1.2 V(vs.Al)was dense and uniform,and the mass fraction of aluminum decreased from 99.61%to 99.10%as the experimental temperature increased from 313 K to 333 K.In this work,the optimum experimental conditions were−1.2 V(vs.Al)and 313 K.At this time,the cathode current efficiency was 97.80%,while the energy consumption was 3.72 kW·h/kg.展开更多
A composite solid electrolyte comprising a Cu-Al bimetallic metal-organic framework(CAB),lithium salt(LiTFSI)and polyethylene oxide(PEO)was fabricated through molecular grafting to enhance the ionic conductivity of th...A composite solid electrolyte comprising a Cu-Al bimetallic metal-organic framework(CAB),lithium salt(LiTFSI)and polyethylene oxide(PEO)was fabricated through molecular grafting to enhance the ionic conductivity of the PEO-based electrolytes.Experimental and molecular dynamics simulation results indicated that the electrolyte with 10 wt.%CAB(PL-CAB-10%)exhibits high ionic conductivity(8.42×10~(-4)S/cm at 60℃),high Li+transference number(0.46),wide electrochemical window(4.91 V),good thermal stability,and outstanding mechanical properties.Furthermore,PL-CAB-10%exhibits excellent cycle stability in both Li-Li symmetric battery and Li/PL-CAB-10%/LiFePO4 asymmetric battery setups.These enhanced performances are primarily attributable to the introduction of the versatile CAB.The abundant metal sites in CAB can react with TFSI~-and PEO through Lewis acid-base interactions,promoting LiTFSI dissociation and improving ionic conductivity.Additionally,regular pores in CAB provide uniformly distributed sites for cation plating during cycling.展开更多
Clean catalytic oxidation has a broad prospect in the modern chemical engineering and energy chemistry fields.However,unexpected over-oxidation and disruptive degradation are frequently induced by excessive reactive o...Clean catalytic oxidation has a broad prospect in the modern chemical engineering and energy chemistry fields.However,unexpected over-oxidation and disruptive degradation are frequently induced by excessive reactive oxygen species(ROS).Herein,we reported a new ROS-free approach to effectively drive O_(2) to be activated into highly reactive surface peroxo species through enzyme-mimicking mechanism.Benefiting from the dual-metal synergy effect between Cu and Co active sites,ROS(H_(2)O_(2) and OH•)is generated in situ while further scavenged completely into surface peroxo species,which gives rise to very high selectivity and extremely high carbon balance.For example,the CuCo/N-C catalyst affords>99.8%conversion and 94.5%selectivity to 2,5-furanedicarboxylic acid at 25℃ for 6 h in the aerobic oxidation of biomass platform 5-hydroxymethylfurfural.Moreover,it achieved exceptional performance in the oxidation of a variety of hydroxyl compounds to organic acids with high yields(89.9%–99.5%)at a mild temperature(25–40℃).This exploration introduces an innovative clue for emulating enzyme catalysts,thereby enriching our comprehension and advancement of biologically inspired catalytic oxidations.展开更多
The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping,which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide sy...The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping,which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems.Recently,however,the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations.Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice.This paper discusses recent advancements in the fabrication,adjustable physical properties,and various applications of freestanding oxide perovskite films.First,we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films.Second,we explore the main functionalities observed in freestanding perovskite oxide thin films,with special attention to the tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states.Next,we encapsulate three representative devices based on freestanding oxide films.Overall,this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.U2067201,52204300)the National 111 Project,China(No.B14034)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2021zzts0297).
文摘The combined reagents of sodium N-oleoylsarcosinate(SNOS)with metal ions(Ca(Ⅱ),Mg(Ⅱ),Cu(Ⅱ),and Pb(Ⅱ))was employed to facilitate the separation of lepidolite from feldspar.The synergistic interaction mechanism of this combined reagent was systematically investigated via contact angle measurements,AFM,FTIR,species distribution calculations,and DFT calculations.The results suggested that Ca(Ⅱ)exhibited the best selectivity for activating lepidolite flotation.SNOS was chemically adsorbed on the Ca(Ⅱ)-activated lepidolite surface with an adsorption energy of−1248.91 kJ/mol while a lower adsorption energy of−598.84 kJ/mol of SNOS on Ca(Ⅱ)-activated feldspar was calculated.Therefore,this combination of SNOS and Ca(Ⅱ)is a promising reagent scheme for the efficient recovery of lithium from aluminosilicate ore.
文摘The use of visible-light responsive photocatalysts for removing heavy metal ions in wastewater has received great attention.However,the development of photocatalysts with high activity and recyclability remains a huge challenge.Herein,a recyclable carbon fiber cloth-supported porous CdS nanorod photocatalyst was fabricated by a two-step hydrothermal treatment using AgVO_(3) nanowires as templates.The results indicated that under visible-light illumination,the carbon cloth-supported porous CdS nanorods showed improved photocatalytic activity for the reduction of Cr(Ⅵ),with an apparent rate constant exceeding that of carbon cloth-supported CdS nanospheres by a factor of 1.65 times.Moreover,the carbon cloth-supported porous CdS nanorods can be easily separated and be reused.This brings a new perspective for developing photocatalysts with high efficiency and recyclability for wastewater treatment.
文摘A gold catalyst of Au/pyrenyl‑graphdiyne(Pyr‑GDY)was prepared by anchoring small size of gold nanoparticles(Au NPs)on the surface of Pyr‑GDY for electrocatalytic nitrogen reduction reaction(eNRR),in which Au NPs with a size of approximately 3.69 nm was evenly distributed on spongy‑like porous Pyr‑GDY.The catalyst exhibited a good electrocatalytic activity for N_(2)reduction in a nitrogen‑saturated electrolyte,with an ammonia yield of 32.1μg·h^(-1)·mg_(cat)^(-1)at-0.3 V(vs RHE),3.5 times higher than that of Au/C(Au NPs anchored on carbon black).In addition,Au/Pyr‑GDY showed a Faraday efficiency(FE)of 26.9%for eNRR,and a good catalysis durability for over 22 h.
基金supported by grants from the National Natural Science Foundation of China(Nos.52031017,51801237)the National Key Laboratory of Science and Technology on High-strength Structural Materials in Central South University,China(No.6142912200106).
文摘This study aims to clarify the mechanisms for the grain boundary(GB)segregation through investigating the absorption of excess solute atoms at GBs in Al−Cu alloys by using the hybrid molecular dynamics/Monte Carlo simulations.Two segregation mechanisms,substitutional and interstitial mechanisms,are observed.The intergranular defects,including dislocations,steps and vacancies,and the intervals in structural units are conductive to the prevalence of interstitial mechanism.And substitutional mechanism is favored by the highly ordered twin GBs.Furthermore,the two mechanisms affect the GB structure differently.It is quantified that interstitial mechanism is less destructive to GB structure than substitutional one,and often leads to a segregation level being up to about 6 times higher than the latter.These findings contribute to atomic scale insights into the microscopic mechanisms about how solute atoms are absorbed by GB structures,and clarify the correlation among intergranular structures,segregation mechanisms and kinetics.
基金the financial supports from the Shaanxi Province Key Research and Development Projects,China(No.2023KXJ-071)the National Natural Science Foundation of China(Nos.52274402,52174381)。
文摘Microstructural evolution and dynamic recrystallization(DRX)mechanisms of a Ti-48Al-2Cr-2Nb(at.%)alloy prepared by selective electron beam melting(SEBM)during hot deformation at 1150℃and 0.1 s^(-1)were investigated by hot compression tests,optical microscope(OM),scanning electron microscope(SEM),electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results show that the initial microstructure of the as-SEBMed alloy exhibits layers of coarseγgrains and fineγ+α_(2)+(α_(2)/γ)lamellar mixture grains alternately along the building direction.During the early stage of hot deformation,deformation twins tend to form within the coarse grains,facilitating subsequent deformation,and a small number of DRX grains appear in the fine-grained regions.With the increase of strain,extensive DRX grains are formed through different DRX mechanisms in both coarse and fine-grained regions,involving discontinuous dynamic recrystallization mechanism(DDRX)in the fine-grained regions and a coexistence of DDRX and continuous dynamic recrystallization(CDRX)in the coarsegrained regions.
文摘Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles of different forms of atomically-dispersed metals(i.e.,single-atoms and atomic clusters)in photocatalytic reactions remain ambiguous.Herein,we developed an ethylenediamine(EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms(Au_(SA)),Au clusters(Au_(C)),and a mixed-phase of Au_(SA)and Au_(C)(Au_(SA+C))on CdS.In addition,we elucidate the synergistic effect of Au_(SA)and Au_(C)in enhancing the photocatalytic performance of CdS substrates for simultaneous CO_(2)reduction and aryl alcohol oxidation.Specifically,Au_(SA)can effectively lower the energy barrier for the CO_(2)→*COOH conversion,while Au_(C)can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation.As a result,the Au_(SA)and Au_(C)co-loaded CdS show impressive overall photocatalytic CO_(2)conversion performance,achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g^(−1)h^(−1),with the selectivities of 93%and 99%,respectively.More importantly,the solar-to-chemical conversion efficiency of Au_(SA+C)/CdS reaches 0.57%,which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature(ca.0.1%).This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions,which is anticipated to pave a new avenue in energy and environmental applications.
文摘Developing highly active alloy catalysts that surpass the performance of platinum group metals in the oxygen reduction reaction(ORR)is critical in electrocatalysis.Gold-based single-atom alloy(AuSAA)clusters are gaining recognition as promising alternatives due to their potential for high activity.However,enhancing its activity of AuSAA clusters remains challenging due to limited insights into its actual active site in alkaline environments.Herein,we studied a variety of Au_(54)M_(1) SAA cluster catalysts and revealed the operando formed MO_(x)(OH)_(y) complex acts as the crucial active site for catalyzing the ORR under the basic solution condition.The observed volcano plot indicates that Au_(54)Co_(1),Au_(54)M_(1),and Au_(54)Ru_(1) clusters can be the optimal Au_(54)M_(1) SAA cluster catalysts for the ORR.Our findings offer new insights into the actual active sites of AuSAA cluster catalysts,which will inform rational catalyst design in experimental settings.
基金supported by the National Naural Science Foudation of China(No.21873013 and No.22273006).
文摘The bimetallic nanostructures that mix a plasmonic metal with a transition metal in the form of the core-shell nanoparticles are promising to promote catalytic performance.But it is still unclear how the heat(hot electrons and phonons)transfers on the interface between two metals.We have designed and synthesized Au@Cu bimetallic nanoparticles with Au as core and Cu as shell.By using transient absorption spectroscopy,we find that there are two plasmon induced heat funneling processes from Au core to Cu shell.One is the electron temperature equilibrium(electron heat transfer)with equilibration time of~560 fs.The other is the lattice temperature equilibrium(lattice heat transfer)with equilibration time of~13 ps.This plasmon induced heat funneling may be universal in similar bimetallic nanostructures,so our finding could contribute to further understanding the catalytic mechanism of bimetallic plasmonic photothermal catalysis.
文摘Metal⁃organic framework(MOF)MIL⁃101 and surface plasmon polariton(SPP)supported gold nanoparti⁃cles(Au NPs)hybrid systems were developed as a highly sensitive and reproducible surface⁃enhanced Raman scat⁃tering(SERS)detection platform,in which a green electrostatic self⁃assembly technology was adopted to construct the substrate.In an aqueous solution,the electronegativity of the particles can be used to prepare the composite sub⁃strate without any surface modifier.Due to the enrichment capacity of MIL⁃101 and the electromagnetic enhance⁃ment from Au NPs,the well⁃designed MIL⁃101/Au composites possessed ultrahigh sensitivity with the detection limit of Rhodamine 6G(R6G)as low as 10^(-10) mol·L^(-1).Meanwhile,the substrate exhibits high stability,excellent reproduc⁃ibility,and recyclability.Additionally,the novel substrate can be explored for direct capture,and sensitively detect pesticide residues such as thiram.
文摘The quest for sustainable energy storage solutions is more critical than ever,with the rise in global energy demand and the urgency of transition from fossil fuels to renewable sources.Carbon nanotubes(CNTs),with their exceptional electrical conduct-ivity and structural integrity,are at the forefront of this endeavor,offering promising ways for the advance of electrochemical energy storage(EES)devices.This review provides an analysis of the synthesis,properties,and applications of CNTs in the context of EES.We explore the evolution of CNT synthesis methods,including arc discharge,laser ablation,and chemical vapor deposition,and highlight the recent developments in metal-organic framework-derived CNTs and a novel CNT aggregate with a three-dimensional ordered macroporous structure.We also examine the role of CNTs in improving the performance of various EES devices such as lith-ium-ion,lithium-metal,lithium-sulfur,sodium,and flexible batteries as well as supercapacitors.We underscore the challenges that remain,including the scalability of CNT synthesis and the integration of CNTs in electrode materials,and propose potential solu-tions and future research directions.The review presents a forward-looking perspective on the pivotal role of CNTs in shaping the fu-ture of sustainable EES technologies.
文摘Thispaper has investigated the coordination and supramolecular assemblies of alkali metal ions,cucurbit[5]uril(Q[5]),and[CdCl_(4)]^(2-)to confirm whether[CdCl_(4)]^(2-)can produce the“honeycomb effect”,induce coordination of alkali metal ions to Q[5],and form linear coordination polymers.In this work,the effect of alkali metal ions on the construction of Q[5]-Cd^(2+)ion system under acidic conditions was investigated.Five complexes were successfully obtained by solvent evaporation method.Among the five crystal structures obtained,it can be observed that the presence of[CdCl_(4)]^(2-)did not result in the complexation of alkali metal ions by the Q[5]molecule.Instead,a bowl-like Cd^(2+)@Q[5]complex was formed.Indeed,[CdCl_(4)]^(2-)did not produce the honeycomb effect but led to the formation of Q[5]-based honeycomb frameworks with hexagonal cellsoccupied by[CdCl_(4)]^(2-).The experimental results show that cadmium ion showed stronger ability to coordinate to Q[5]in HCl solution.
文摘Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.
文摘Industrial activities such as smelting emissions,mineral combustion and industrial wastewater discharge might lead to copper pollution in the environment.This kind of copper pollution has harmful effects on aquatic o rganisms,plants and animals through direct or indirect exposure.However,the current understanding of the toxicity of copper is rather limited.Copper overload can perturb intracellular homeostasis and induce oxidative stress and e ven cell death.Recently,cuproptosis has been identified as a copper-dependent form of cell death induced by o xidative stress in mitochondria.We uncover here that zinc transporter 1(ZNT1)is an important regulator involved in cuproptosis.Firstly,we established the copper overload-induced cell death model with the overexpression of copper importer SLC31A1 in HeLa cells.Using this model,we conducted unbiased genome-wide CRISPR-Cas9 screens in cells treated with copper.Our results revealed a significant enrichment of ZNT1 gene in both library A and library B plasmids.Knocking out of ZNT1 in HeLa cells notably prevented cuproptosis.Subsequent knockout of metal transcription factor 1(MTF1)in ZNT1-deficient cells nearly abolished their ability to resist copper-induced cell death.However,overexpression of metallothionein 1X(MT1X)in the double-knockout cells could p artially restored the resistance to cuproptosis by loss of MTF1.Mechanistically,knockout of ZNT1 could promote MT1X expression by activating MTF1.As a consequence,the interaction between MT1X and copper was e nhanced,reducing the flow of copper into mitochondria and eliminating mitochondria damage.Taken together,this study reveals the important role of ZNT1 in cuproptosis and shows MTF1-MT1X axis mediated resistance to c uproptosis.Moreover,our study will help to understand the regulatory mechanism of cellular and systemic copper homeostasis under copper overload,and present insights into novel treatments for damages caused by both genetic copper overload diseases and environmental copper contamination.
基金Project(52004062)supported by the National Natural Science Foundation of ChinaProject(2020-MS-084)supported by the Natural Science Foundation of Liaoning Province,ChinaProject(N2125014)supported by the Fundamental Research Funds for the Central Universities,China。
文摘The electrochemical behavior of Al(Ⅲ)in urea-1-butyl-3-methylimidazolium chloride-aluminum chloride(urea-BMIC-AlCl_(3))ionic liquids,and the effect of potential and temperature on the characterization of cathode products,current efficiency and energy consumption of aluminum electrorefining have been investigated.Cyclic voltammetry showed that the electrochemical reduction of Al(Ⅲ)was a one-step three-electron-transfer irreversible reaction,and the electrochemical reaction was controlled by diffusion.The diffusion coefficient of Al(Ⅲ)in urea-BMIC-AlCl_(3)ionic liquids at 313 K was 1.94×10^(−7)cm^(2)/s.The 7075 aluminum alloy was used as an anode for electrorefining,and the cathode products were analyzed by XRD,SEM and EDS.The results from XRD analysis indicated that the main phase of the cathode products was aluminum.The results from SEM and EDS characterization revealed that the cathode product obtained by electrorefining−1.2 V(vs.Al)was dense and uniform,and the mass fraction of aluminum decreased from 99.61%to 99.10%as the experimental temperature increased from 313 K to 333 K.In this work,the optimum experimental conditions were−1.2 V(vs.Al)and 313 K.At this time,the cathode current efficiency was 97.80%,while the energy consumption was 3.72 kW·h/kg.
基金supported by the National Natural Science Foundation of China(No.21501015)the Hunan Provincial Natural Science Foundation,China(No.2022JJ30604)Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,China(No.2022CL01)。
文摘A composite solid electrolyte comprising a Cu-Al bimetallic metal-organic framework(CAB),lithium salt(LiTFSI)and polyethylene oxide(PEO)was fabricated through molecular grafting to enhance the ionic conductivity of the PEO-based electrolytes.Experimental and molecular dynamics simulation results indicated that the electrolyte with 10 wt.%CAB(PL-CAB-10%)exhibits high ionic conductivity(8.42×10~(-4)S/cm at 60℃),high Li+transference number(0.46),wide electrochemical window(4.91 V),good thermal stability,and outstanding mechanical properties.Furthermore,PL-CAB-10%exhibits excellent cycle stability in both Li-Li symmetric battery and Li/PL-CAB-10%/LiFePO4 asymmetric battery setups.These enhanced performances are primarily attributable to the introduction of the versatile CAB.The abundant metal sites in CAB can react with TFSI~-and PEO through Lewis acid-base interactions,promoting LiTFSI dissociation and improving ionic conductivity.Additionally,regular pores in CAB provide uniformly distributed sites for cation plating during cycling.
文摘Clean catalytic oxidation has a broad prospect in the modern chemical engineering and energy chemistry fields.However,unexpected over-oxidation and disruptive degradation are frequently induced by excessive reactive oxygen species(ROS).Herein,we reported a new ROS-free approach to effectively drive O_(2) to be activated into highly reactive surface peroxo species through enzyme-mimicking mechanism.Benefiting from the dual-metal synergy effect between Cu and Co active sites,ROS(H_(2)O_(2) and OH•)is generated in situ while further scavenged completely into surface peroxo species,which gives rise to very high selectivity and extremely high carbon balance.For example,the CuCo/N-C catalyst affords>99.8%conversion and 94.5%selectivity to 2,5-furanedicarboxylic acid at 25℃ for 6 h in the aerobic oxidation of biomass platform 5-hydroxymethylfurfural.Moreover,it achieved exceptional performance in the oxidation of a variety of hydroxyl compounds to organic acids with high yields(89.9%–99.5%)at a mild temperature(25–40℃).This exploration introduces an innovative clue for emulating enzyme catalysts,thereby enriching our comprehension and advancement of biologically inspired catalytic oxidations.
基金supported by the Fundamental Research Funds for the Central Universities(WK9990000102,WK2030000035).
文摘The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping,which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems.Recently,however,the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations.Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice.This paper discusses recent advancements in the fabrication,adjustable physical properties,and various applications of freestanding oxide perovskite films.First,we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films.Second,we explore the main functionalities observed in freestanding perovskite oxide thin films,with special attention to the tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states.Next,we encapsulate three representative devices based on freestanding oxide films.Overall,this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics.