Nano zero-valent iron(nZVI)is widely used in soil remediation due to its high reactivity.However,the easy agglomeration,poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its a...Nano zero-valent iron(nZVI)is widely used in soil remediation due to its high reactivity.However,the easy agglomeration,poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remediation,especially in high concentration of Cr-contaminated soil.Herein,we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI.Along with the presence of biochar,97.0%and 96.6%Cr immobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation.In addition,the immobilization efficiency of Cr(VI)only decreased by 5.1%through CMC-nZVI/BC treatment after 10 weeks aging in air,attributing to the strong antioxidation ability.As for the surrounding Crcontaminated groundwater,the Cr(VI)removal capacity of CMC-nZVI/BC was evaluated under different reaction conditions through column experiments and COMSOL Multiphysics.CMC-nZVI/BC could efficiently remove 85%of Cr(VI)in about 400 hr when the initial Cr(VI)concentration was 40 mg/L and the flow rate was 0.5 mL/min.This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concentrations of Cr-contaminated soils.展开更多
Hydrogen evolution reaction(HER)plays a crucial role in developing clean and renewable hydrogen energy technologies.However,conventional HER catalysts rely on expensive and scarce noble metals,which is a significant c...Hydrogen evolution reaction(HER)plays a crucial role in developing clean and renewable hydrogen energy technologies.However,conventional HER catalysts rely on expensive and scarce noble metals,which is a significant challenge for practical application.Recently,twodimensional transition metal dichalcogenides(2D-TMDs)have emerged as attractive and cost-effective alternatives for efficient electrocatalysis in the HER.Substantial efforts have been dedicated to advancing the synthesis and application of 2D-TMDs.This review highlights the design and synthesis of high-performance 2D-TMDs-based HER electrocatalysts by combining theoretical calculations with experimental methods.Subsequently,recent advances in synthesizing different types of 2D TMDs with enhanced HER activity are summarized.Finally,the conclusion and perspectives of the 2D TMDs-based HER electrocatalysts are discussed.We expect that this review will provide new insights into the design and development of highly efficient 2D TMDs-based HER electrocatalysts for industrial applications.展开更多
Magnesium hydride(MgH_(2))has garnered significant attention as a promising material for high-capacity hydrogen storage.However,its commercial application remains challenging due to the high operating temperature and ...Magnesium hydride(MgH_(2))has garnered significant attention as a promising material for high-capacity hydrogen storage.However,its commercial application remains challenging due to the high operating temperature and slow reaction kinetics.In this study,melt-spun Ti_(45)Cr_(40)Nb_(15)(with a BCC phase)hydride(designated as TiCrNbH_(x-)MS)was synthesized and used to form a nano-multiphase composite to improve the de-/rehydrogenation properties of MgH_(2) through ball milling.The incorporation of TiCrNbH_(x-)MS was shown to significantly enhance the hydrogen de-/rehydrogenation properties of MgH_(2).The MgH_(2)+20 wt%TiCrNbH_(x-)MS composite exhibits an appealing initial dehydrogenation temperature of 163℃ and can absorb hydrogen at room temperature.Notably,it releases 5.8 wt% hydrogen in 700 s at 230℃ and recharges 4.3 wt%hydrogen in just 2 mins at 150℃.Even after 100 cycles,it retains a reversible hydrogen capacity of 4.98 wt%.Kinetic analysis revealed that the dehydrogenation rate follows the Chou surface penetration model.Microstructural analysis showed that the FCC phase of the melt-spun TiCrNbH_(x-)MS hydride reversibly transformed into the BCC phase during the de-/rehydrogenation process in the composite.Numerous phase interfaces were generated and uniformly dispersed on the MgH_(2) surface,providing additional hydrogen diffusion pathways and heterogeneous nucleation sites for Mg/MgH_(2),thereby further improving the hydrogen de-/rehydrogenation kinetics of the system.This study offers valuable insights into the use of multiphase composites to enhance MgH_(2) performance.展开更多
The investigation on Curie temperature and magnetocaloric effect of the FeCrMoCBYNi bulk metallic glass(BMG) with different crystallized phases was carried out by XRD,TEM and PPMS. The experimental results show that t...The investigation on Curie temperature and magnetocaloric effect of the FeCrMoCBYNi bulk metallic glass(BMG) with different crystallized phases was carried out by XRD,TEM and PPMS. The experimental results show that the Curie temperature(T_c) of Fe_(45)Cr_(15)Mo_(14)C_(15)B_6 Y_2 Ni_3 BMG with different annealing condition reaches a highest value of 95 K. The value of magnetic entropy change △S_M(T) of Sample 3 reaches a maxima of 0.48 J/(kg·K) at Tc temperature, which result from the interaction among the precipitated phases of(Fe,Cr)_(23)(C,B)_6, Fe_3 Mo_3 C and residual amorphous phase. Based on the experiment results, it can be obtained that the Curie temperature, magnetocaloric effect can reach their optimal value at low temperature, when the content of amorphous phase and precipitated phases type run up to certain value. The magnetic properties of Sample 1 with full amorphous phase and Sample 4 with full crystalline phase will both decrease.展开更多
Superlattice hydrogen storage alloys offer a compelling advantage with rapid hydriding rate and high storage capacity.However,its practical applications face challenges including complex structure,low dehydriding capa...Superlattice hydrogen storage alloys offer a compelling advantage with rapid hydriding rate and high storage capacity.However,its practical applications face challenges including complex structure,low dehydriding capacity,and cyclic instability.In this work,we successfully prepared La_(0.66)Mg_(0.34)Ni_(3.5-x)Co_(x) superlattice hydrogen storage alloys with enhanced dehydriding capacity and stability by partially substituting Co for Ni.X-ray diffraction(XRD)refinements analysis reveals the presence of(La,Mg)_(3)Ni_(9),(La,Mg)_5Ni_(19),and LaNi_(5) phases within the alloy.Following Co substitution in the La_(0.06)Mg_(0.34)Ni_(3.4)Co_(0.1)alloy,there is a significant increase in content of the(La,Mg)_(3)Ni_(9) phase and a reduction in the hysteresis factor,resulting in an improved reversible hydrogen storage capacity from 1.45 wt%to 1.60 wt%.The dehydriding kinetics of the alloy is controlled by diffusion model with an activation energy of 8.40 kJ/mol.Furthermore,the dehydriding enthalpy value of the Co-substituted alloy decreases from 30.84 to 29.85 kJ/mol.Impressively,the cycling performance of the alloy after Co substitution exhibits excellent stability,with a capacity retention rate of 92.3%after 100 cycles.These findings provide valuable insights for the development of cost-effective hydrogen storage materials.展开更多
Metallic glasses have recently attracted great attention in terms of degrading dyes and other organic pollutants as an environmentally friendly material for wastewater remediation.Herein,we report a new type of amorph...Metallic glasses have recently attracted great attention in terms of degrading dyes and other organic pollutants as an environmentally friendly material for wastewater remediation.Herein,we report a new type of amorphous catalyst Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) hollow balls.Results demonstrate that the catalyst can still completely decolorize the 20 mg/L methylene blue(MB)solution after reused for 50 times under conditions of pH=5,catalyst content 0.5 g/L,and temperature 80°C.The catalyst is easily broken during degradation,so the inner surface also provides additional active sites.The Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) amorphous alloy hollow balls were characterized by energy dispersive X-ray specroscopy(EDS),scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS),respectively.The elements in the catalytic system have a synergistic catalytic effect.Redox cycle Fe^(2+)/Fe^(3+),Co^(2+)/Co^(3+)and Mo^(4+)/Mo^(6+) promote mutual conversion and accelerate the catalytic process of their reaction with H_(2)O_(2),forming a self-stable redox cycle process.Among them,Fe^(2+)promotes the conversion of Co^(3+)to Co^(2+),and Mo^(4+) promotes the conversion of Fe^(3+)to Fe^(2+),mainly Fe^(2+)and Co^(2+)react with H_(2)O_(2) to generate•OH.Mo and Cr elements form MoO_(2) and Cr_(2)O_(3) plasma compounds on the surface,which act as a protective film to make the catalyst more stable and be repeated used more frequently.展开更多
Laser 3D printing,also known as laser additive manufacturing(LAM),is favored for its ability to form bulk metallic glass(BMG)and its composite materials(BMGcs)with freeform geometries.In this work,two different kinds ...Laser 3D printing,also known as laser additive manufacturing(LAM),is favored for its ability to form bulk metallic glass(BMG)and its composite materials(BMGcs)with freeform geometries.In this work,two different kinds of Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2)amorphous coatings(A and B)were prepared by using LAM technology under air-and water-cooled conditions,respectively;meanwhile,to reduce the cracks generated due to the residual thermal stresses,coating C obtained by air-sweep annealing of B with a low energy-density laser.The morphology and amorphous content and microstructure of the coatings were investigated,the results show many cracks in coating B deposited under water-cooled conditions,and its microstructure shows an amorphous-crystal-nanocrystalline mixed structure.Cracking was suppressed in coating C,obtained by air-sweep annealing based on coating B,but the amorphous content was reduced from 32.6 to 13.4%.And the hardness and corrosion resistance of the coating will increase with the increase in the amorphous content.Finally,the internal friction behavior of a BMGcs was prepared on the basis of the process of sample C is compared with that of as-cast amorphous alloys.The results show that the low temperature internal friction behavior of BMGcs is affected by the defects produced during printing,and the high temperature internal friction behavior is affected by the precipitated hard phase.展开更多
Developing novel oxygen reduction reaction(ORR)catalysts with high activity is urgent for proton exchange membrane fuel cells.Herein,we investigated a group of size-dependent Pt-based catalysts as promising ORR cataly...Developing novel oxygen reduction reaction(ORR)catalysts with high activity is urgent for proton exchange membrane fuel cells.Herein,we investigated a group of size-dependent Pt-based catalysts as promising ORR catalysts by density functional theory calculations,ranging from single-atom,nanocluster to bulk Pt catalysts.The results showed that the ORR overpotential of these Pt-based catalysts increased when its size enlarged to the nanoparticle scale or reduced to the single-atom scale,and the Pt_(38)cluster had the lowest ORR overpotential(0.46 V)compared with that of Pt_(111)(0.57 V)and single atom Pt(0.7 V).Moreover,we established a volcano curve relationship between the ORR overpotential and binding energy of O*(ΔE_(O*),confirming the intermediate species anchored on Pt38cluster with suitable binding energy located at top of volcano curve.The interaction between intermediate species and Pt-based catalysts were also investigated by the charge distribution and projected density of state and which further confirmed the results of volcano curve.展开更多
Single pass compression tests were conducted on Gleeblel500 thermal simulator. The effect of different deformation parameters on the grain size of dynamically recrystallized austenite was analyzed. A mathematical mode...Single pass compression tests were conducted on Gleeblel500 thermal simulator. The effect of different deformation parameters on the grain size of dynamically recrystallized austenite was analyzed. A mathematical model of dynamic recrystallization and a material database of JB800 steel, whose tensile strength is above 800 MPa, were set up. A subprogram was compiled using Fortran language and called by Marc finite element software. A thermal coupled elastoplastic finite element model was established to simulate the compression process. The grain size of recrystallized austenite obtained by different recrystallization models was simulated. The results show that the optimized dynamic recrystallization model of JB800 bainitic steel has a higher precision and yields good agreement with metallographic observations.展开更多
Post-exposure prophylaxis(PEP)represents the critical intervention for preventing rabies and comprises three essential components:thorough wound cleansing,vaccination,and administration of rabies immunoglobulin(RIG)or...Post-exposure prophylaxis(PEP)represents the critical intervention for preventing rabies and comprises three essential components:thorough wound cleansing,vaccination,and administration of rabies immunoglobulin(RIG)or monoclonal antibodies(mAbs)for category III exposures.The World Health Organization(WHO)endorses the use of mAb cocktails as an effective replacement for RIG in PEP protocols.Since 2016,four anti-rabies monoclonal antibodies(RmAbs)have received clinical approval for use in India and China.This article provides an overview of the current research status of RmAb.By reviewing clinical studies related to RmAb,it highlights the clinical advantages of RmAb over HRIG in terms of efficacy,accessibility,safety,acceptability,and clinical application in special populations.Additionally,it explores the future clinical prospects of RmAb,including their use in extremely high-risk cases,their impact on circulating antibodies,and their potential role in rabies treatment.展开更多
The key technologies of fuel cell systems have a great impact on their performance and lifetime.However,most of the current analyses in reviews only focus on a single system or one aspect of the technology.It is highl...The key technologies of fuel cell systems have a great impact on their performance and lifetime.However,most of the current analyses in reviews only focus on a single system or one aspect of the technology.It is highly necessary to systematically analyze the new development and research trends of vehicular fuel cell systems.This paper proposes a quantitative and visual analysis based on bibliometrics to more intuitively reveal the research direction in this field.Key information on hydrogen/air subsystems,energy management strategies,and thermal management subsystems are analyzed by combining the literature analysis and technical discussion.In detail,the possible reasons behind the variations in the number of articles published within different periods of the subsystem are revealed.Then,through qualitative analysis of representative papers with high citations in different periods,the main research methods adopted by scholars in different periods are derived.Finally,the technology research trends of control methods that need to be addressed in the future are summarized for different subsystems.This paper provides a reference for researchers in the field to understand more clearly the current trends in the field and provide new ideas to break through the challenges of developing high-performance fuel cell systems.展开更多
Single-atom catalysts(SACs)attract significant attention owing to their high catalytic activity,high metal atom utilization efficiency,and well-defined and configurable active sites.However,achieving single-atom dispe...Single-atom catalysts(SACs)attract significant attention owing to their high catalytic activity,high metal atom utilization efficiency,and well-defined and configurable active sites.However,achieving single-atom dispersion of active metals at high metal loadings remains challenging,limiting the performance of SACs in many practical applications.Herein,we provide a comprehensive review of recent methods developed for synthesizing high-loading SACs,critically exploring their advantages,limitations,and wider applicability.Additionally,we showcase the benefits of high-loading SACs in the oxygen reduction reaction(ORR),water electrolysis,photocatalytic hydrogen production and CO oxidation.Although great recent progress has been made in the synthesis of high loading SACs,simple and universal routes that allowed the preprogrammed preparation of single metal and multi-metal SACs with specific metal coordination need to be discovered.展开更多
Developing single-atom Fe–N_(4)/C catalysts is crucial for the large-scale implementation of proton exchange membrane fuel cells(PEMFCs).While Fe–N_(4)/C catalysts are inherently active in accelerating the slow ORR ...Developing single-atom Fe–N_(4)/C catalysts is crucial for the large-scale implementation of proton exchange membrane fuel cells(PEMFCs).While Fe–N_(4)/C catalysts are inherently active in accelerating the slow ORR process,their performance is still inferior to that of Pt/C.Herein,a trace Co-doped Fe single-atom catalyst(Fe(tCo)–N–C)containing more active Fe_(2)N_(8) sites has been synthesized.Interestingly,compared with typical FeN4 sites in an Fe–N–C electrocatalyst,the Fe_(2)N_(8) sites generate a larger Fe–N bond length due to Co-doping.The elongated Fe–N bond in Fe_(2)N_(8) lowers the d-band center and charge density of iron sites,enhancing the ORR process by facilitating the formation of*OOH and generation and desorption of*OH.Fe(tCo)–N–C manifested excellent acidic and alkaline ORR activity,with a half-wave potential(E_(1/2))of 0.80 V in HClO_(4) solution and 0.89 V in KOH medium.More importantly,high peak power densities(Pmax)were realized by applying Fe(tCo)–N–C in PEMFCs,with the Pmax reaching 890 mW cm^(-2) in H_(2)–O_(2) and 380 mW cm^(-2) in H_(2)–air.Additionally,trace Co dopants in the catalyst improved carbon graphitization and provided high ORR catalytic stability.This research introduces an innovative approach to engineering highly active Fe_(2)N_(8) sites,providing valuable insights for the sustainable progress of PEMFC technology.展开更多
At present,the catalysts commercially used for the oxygen reduction reaction of the cathode of proton exchange membrane fuel cells(PEMFCs)are carbon-supported platinum-based catalysts.However,the carbon supports are s...At present,the catalysts commercially used for the oxygen reduction reaction of the cathode of proton exchange membrane fuel cells(PEMFCs)are carbon-supported platinum-based catalysts.However,the carbon supports are susceptible to corrosion under harsh working conditions,which greatly shortens the life of the catalysts.Highly stable carbon supports are urgently required for high-performance PEMFCs.In this work,we developed structure-stable and highly graphitized three-dimensional network carbon nanofibers(CNF)derived from polyaniline by heat treatment at 1200℃.The CNF-1200-based catalyst(PtNi/CNF-1200)loaded with PtNi nanoparticles showed excellent stability.After 5000 cycles from 1.0 to 1.5 V in oxygen saturated 0.1 M HClO_(4) electrolyte,the losses in the half-wave potential and mass activity were only 5 mV and 15%,respectively,far lower than those of commercial Pt/C.The high graphitization degree of CNF-1200 promotes the corrosion resistance of the catalyst.In addition,nitrogen doping effectively facilitates the catalyst–support interaction,stabilizes the highly dispersed PtNi nanoparticles,and improves the stability and activity of PtNi/CNF-1200.展开更多
基金supported by the National Key Research and Development Program of China(No.2020YFC1808701)the Fundamental Research Funds for the Central Universities(No.buctrc202232).
文摘Nano zero-valent iron(nZVI)is widely used in soil remediation due to its high reactivity.However,the easy agglomeration,poor antioxidant ability and passivation layer of Fe-Cr coprecipitates of nZVI have limited its application scale in Cr-contaminated soil remediation,especially in high concentration of Cr-contaminated soil.Herein,we found that the carboxymethyl cellulose on nZVI particles could increase the zeta potential value of soil and change the phase of nZVI.Along with the presence of biochar,97.0%and 96.6%Cr immobilization efficiency through CMC-nZVI/BC were respectively achieved in high and low concentrations of Cr-contaminated soils after 90-days remediation.In addition,the immobilization efficiency of Cr(VI)only decreased by 5.1%through CMC-nZVI/BC treatment after 10 weeks aging in air,attributing to the strong antioxidation ability.As for the surrounding Crcontaminated groundwater,the Cr(VI)removal capacity of CMC-nZVI/BC was evaluated under different reaction conditions through column experiments and COMSOL Multiphysics.CMC-nZVI/BC could efficiently remove 85%of Cr(VI)in about 400 hr when the initial Cr(VI)concentration was 40 mg/L and the flow rate was 0.5 mL/min.This study demonstrates that uniformly dispersed CMC-nZVI/BC has an excellent remediation effect on different concentrations of Cr-contaminated soils.
基金supported by the National Key Projects for Fundamental Research and Development of China(2021YFA1500803)the National Natural Science Foundation of China(51825205,52120105002,22088102,22279150,22209186)+1 种基金the Beijing Natural Science Foundation(2222080)the Youth Innovation Promotion Association of the CAS(Y2021011)。
文摘Hydrogen evolution reaction(HER)plays a crucial role in developing clean and renewable hydrogen energy technologies.However,conventional HER catalysts rely on expensive and scarce noble metals,which is a significant challenge for practical application.Recently,twodimensional transition metal dichalcogenides(2D-TMDs)have emerged as attractive and cost-effective alternatives for efficient electrocatalysis in the HER.Substantial efforts have been dedicated to advancing the synthesis and application of 2D-TMDs.This review highlights the design and synthesis of high-performance 2D-TMDs-based HER electrocatalysts by combining theoretical calculations with experimental methods.Subsequently,recent advances in synthesizing different types of 2D TMDs with enhanced HER activity are summarized.Finally,the conclusion and perspectives of the 2D TMDs-based HER electrocatalysts are discussed.We expect that this review will provide new insights into the design and development of highly efficient 2D TMDs-based HER electrocatalysts for industrial applications.
基金financially supported by the National Key Research and Development program of China(2022YFB3504700)the National Natural Science Foundation of China(U23A20128)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0400304)the Research Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(No.E355B0020).
文摘Magnesium hydride(MgH_(2))has garnered significant attention as a promising material for high-capacity hydrogen storage.However,its commercial application remains challenging due to the high operating temperature and slow reaction kinetics.In this study,melt-spun Ti_(45)Cr_(40)Nb_(15)(with a BCC phase)hydride(designated as TiCrNbH_(x-)MS)was synthesized and used to form a nano-multiphase composite to improve the de-/rehydrogenation properties of MgH_(2) through ball milling.The incorporation of TiCrNbH_(x-)MS was shown to significantly enhance the hydrogen de-/rehydrogenation properties of MgH_(2).The MgH_(2)+20 wt%TiCrNbH_(x-)MS composite exhibits an appealing initial dehydrogenation temperature of 163℃ and can absorb hydrogen at room temperature.Notably,it releases 5.8 wt% hydrogen in 700 s at 230℃ and recharges 4.3 wt%hydrogen in just 2 mins at 150℃.Even after 100 cycles,it retains a reversible hydrogen capacity of 4.98 wt%.Kinetic analysis revealed that the dehydrogenation rate follows the Chou surface penetration model.Microstructural analysis showed that the FCC phase of the melt-spun TiCrNbH_(x-)MS hydride reversibly transformed into the BCC phase during the de-/rehydrogenation process in the composite.Numerous phase interfaces were generated and uniformly dispersed on the MgH_(2) surface,providing additional hydrogen diffusion pathways and heterogeneous nucleation sites for Mg/MgH_(2),thereby further improving the hydrogen de-/rehydrogenation kinetics of the system.This study offers valuable insights into the use of multiphase composites to enhance MgH_(2) performance.
文摘离子液体(ILs)改性固体催化剂是一种构筑高效电催化界面的方法。为了研究ILs阳离子在催化剂中Pt表面对燃料电池中氧还原反应(ORR)性能的影响,本研究自主合成了两种疏水质子型ILs ([EIM][NTf_(2)],[BIM][NTf_(2)])和两种疏水非质子型ILs([EMIM][NTf_(2)],[BMIM][NTf_(2)]),并对商业化Pt/C进行改性。在本研究采用的咪唑类疏水ILs中,质子型ILs改性催化剂的ORR活性均高于非质子型ILs改性催化剂,其中,由1-丁基咪唑双(三氟甲磺酰)亚胺改性后的催化剂([BIM][NTf_(2)]@Pt/C)活性最高。在酸性半电池中ORR半波电位高达0.913 V (vs.RHE),质量活性提升至商业化Pt/C的1.73倍,比活性提升至商业化Pt/C的3倍,同时达到5000圈循环后半波电位仅下降12 mV,性能仍高于商业化Pt/C。进一步材料表征和电化学测试表明,[BIM][NTf_(2)]@Pt/C电催化活性的增强归因于该ILs可增多Pt表面参与反应活性位点、强化Pt表面质子及质量传递,并可有效抑制Pt纳米颗粒溶解,从而起到了增强ORR活性及稳定性的作用。本研究深化了对ILs@Pt界面协同电催化机理的认识,为设计下一代高效燃料电池催化剂提供了理论依据。
基金supported by the National Natural Science Foundation of China(51741105)
文摘The investigation on Curie temperature and magnetocaloric effect of the FeCrMoCBYNi bulk metallic glass(BMG) with different crystallized phases was carried out by XRD,TEM and PPMS. The experimental results show that the Curie temperature(T_c) of Fe_(45)Cr_(15)Mo_(14)C_(15)B_6 Y_2 Ni_3 BMG with different annealing condition reaches a highest value of 95 K. The value of magnetic entropy change △S_M(T) of Sample 3 reaches a maxima of 0.48 J/(kg·K) at Tc temperature, which result from the interaction among the precipitated phases of(Fe,Cr)_(23)(C,B)_6, Fe_3 Mo_3 C and residual amorphous phase. Based on the experiment results, it can be obtained that the Curie temperature, magnetocaloric effect can reach their optimal value at low temperature, when the content of amorphous phase and precipitated phases type run up to certain value. The magnetic properties of Sample 1 with full amorphous phase and Sample 4 with full crystalline phase will both decrease.
基金Project supported by the National Key R&D Program of China(2022YFB3504700)。
文摘Superlattice hydrogen storage alloys offer a compelling advantage with rapid hydriding rate and high storage capacity.However,its practical applications face challenges including complex structure,low dehydriding capacity,and cyclic instability.In this work,we successfully prepared La_(0.66)Mg_(0.34)Ni_(3.5-x)Co_(x) superlattice hydrogen storage alloys with enhanced dehydriding capacity and stability by partially substituting Co for Ni.X-ray diffraction(XRD)refinements analysis reveals the presence of(La,Mg)_(3)Ni_(9),(La,Mg)_5Ni_(19),and LaNi_(5) phases within the alloy.Following Co substitution in the La_(0.06)Mg_(0.34)Ni_(3.4)Co_(0.1)alloy,there is a significant increase in content of the(La,Mg)_(3)Ni_(9) phase and a reduction in the hysteresis factor,resulting in an improved reversible hydrogen storage capacity from 1.45 wt%to 1.60 wt%.The dehydriding kinetics of the alloy is controlled by diffusion model with an activation energy of 8.40 kJ/mol.Furthermore,the dehydriding enthalpy value of the Co-substituted alloy decreases from 30.84 to 29.85 kJ/mol.Impressively,the cycling performance of the alloy after Co substitution exhibits excellent stability,with a capacity retention rate of 92.3%after 100 cycles.These findings provide valuable insights for the development of cost-effective hydrogen storage materials.
基金Project supported by the Research Fund of State Key Laboratory for Marine Corrosion and Protection of Luoyang Ship Material Research Institute (LSMRI)(KF190413)。
文摘Metallic glasses have recently attracted great attention in terms of degrading dyes and other organic pollutants as an environmentally friendly material for wastewater remediation.Herein,we report a new type of amorphous catalyst Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) hollow balls.Results demonstrate that the catalyst can still completely decolorize the 20 mg/L methylene blue(MB)solution after reused for 50 times under conditions of pH=5,catalyst content 0.5 g/L,and temperature 80°C.The catalyst is easily broken during degradation,so the inner surface also provides additional active sites.The Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) amorphous alloy hollow balls were characterized by energy dispersive X-ray specroscopy(EDS),scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS),respectively.The elements in the catalytic system have a synergistic catalytic effect.Redox cycle Fe^(2+)/Fe^(3+),Co^(2+)/Co^(3+)and Mo^(4+)/Mo^(6+) promote mutual conversion and accelerate the catalytic process of their reaction with H_(2)O_(2),forming a self-stable redox cycle process.Among them,Fe^(2+)promotes the conversion of Co^(3+)to Co^(2+),and Mo^(4+) promotes the conversion of Fe^(3+)to Fe^(2+),mainly Fe^(2+)and Co^(2+)react with H_(2)O_(2) to generate•OH.Mo and Cr elements form MoO_(2) and Cr_(2)O_(3) plasma compounds on the surface,which act as a protective film to make the catalyst more stable and be repeated used more frequently.
基金This work was supported by the National Natural Science Foundation of China(No.52161028)the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(No.20213BCJ22017).
文摘Laser 3D printing,also known as laser additive manufacturing(LAM),is favored for its ability to form bulk metallic glass(BMG)and its composite materials(BMGcs)with freeform geometries.In this work,two different kinds of Fe_(41)Co_(7)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2)amorphous coatings(A and B)were prepared by using LAM technology under air-and water-cooled conditions,respectively;meanwhile,to reduce the cracks generated due to the residual thermal stresses,coating C obtained by air-sweep annealing of B with a low energy-density laser.The morphology and amorphous content and microstructure of the coatings were investigated,the results show many cracks in coating B deposited under water-cooled conditions,and its microstructure shows an amorphous-crystal-nanocrystalline mixed structure.Cracking was suppressed in coating C,obtained by air-sweep annealing based on coating B,but the amorphous content was reduced from 32.6 to 13.4%.And the hardness and corrosion resistance of the coating will increase with the increase in the amorphous content.Finally,the internal friction behavior of a BMGcs was prepared on the basis of the process of sample C is compared with that of as-cast amorphous alloys.The results show that the low temperature internal friction behavior of BMGcs is affected by the defects produced during printing,and the high temperature internal friction behavior is affected by the precipitated hard phase.
基金supported by the National Natural Science Foundation of China(92061125,21978294)Beijing Natural Science Foundation(Z200012)+3 种基金Jiangxi Natural Science Foundation(20212ACB213009)DNL Cooperation Fund,CAS(DNL201921)Self-deployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055B003)Hebei Natural Science Foundation(B2020103043)。
文摘Developing novel oxygen reduction reaction(ORR)catalysts with high activity is urgent for proton exchange membrane fuel cells.Herein,we investigated a group of size-dependent Pt-based catalysts as promising ORR catalysts by density functional theory calculations,ranging from single-atom,nanocluster to bulk Pt catalysts.The results showed that the ORR overpotential of these Pt-based catalysts increased when its size enlarged to the nanoparticle scale or reduced to the single-atom scale,and the Pt_(38)cluster had the lowest ORR overpotential(0.46 V)compared with that of Pt_(111)(0.57 V)and single atom Pt(0.7 V).Moreover,we established a volcano curve relationship between the ORR overpotential and binding energy of O*(ΔE_(O*),confirming the intermediate species anchored on Pt38cluster with suitable binding energy located at top of volcano curve.The interaction between intermediate species and Pt-based catalysts were also investigated by the charge distribution and projected density of state and which further confirmed the results of volcano curve.
基金the National Natural Science Foundation of China(No.50334010)
文摘Single pass compression tests were conducted on Gleeblel500 thermal simulator. The effect of different deformation parameters on the grain size of dynamically recrystallized austenite was analyzed. A mathematical model of dynamic recrystallization and a material database of JB800 steel, whose tensile strength is above 800 MPa, were set up. A subprogram was compiled using Fortran language and called by Marc finite element software. A thermal coupled elastoplastic finite element model was established to simulate the compression process. The grain size of recrystallized austenite obtained by different recrystallization models was simulated. The results show that the optimized dynamic recrystallization model of JB800 bainitic steel has a higher precision and yields good agreement with metallographic observations.
基金Supported by the Talent Development Plan for High-level Public Health Technical Personnel Project(Subject leader−01-47).
文摘Post-exposure prophylaxis(PEP)represents the critical intervention for preventing rabies and comprises three essential components:thorough wound cleansing,vaccination,and administration of rabies immunoglobulin(RIG)or monoclonal antibodies(mAbs)for category III exposures.The World Health Organization(WHO)endorses the use of mAb cocktails as an effective replacement for RIG in PEP protocols.Since 2016,four anti-rabies monoclonal antibodies(RmAbs)have received clinical approval for use in India and China.This article provides an overview of the current research status of RmAb.By reviewing clinical studies related to RmAb,it highlights the clinical advantages of RmAb over HRIG in terms of efficacy,accessibility,safety,acceptability,and clinical application in special populations.Additionally,it explores the future clinical prospects of RmAb,including their use in extremely high-risk cases,their impact on circulating antibodies,and their potential role in rabies treatment.
基金supported in part by the National Key Research and Development Program(No.2022 YFB3504705)the State Key Laboratory of Mechanical Transmission in Chongqing University(No.SKLMT-ZZKT-2022R02)+1 种基金the Automobile Collaboration Center Unveiling Project(No.2022CDJDX-004)the Mechanical transmission laboratory independent topic general project,multi-field coupling mechanism,and performance improvement method of the electromechanical transmission system(No.SKLMT-ZZKT-2022M08).
文摘The key technologies of fuel cell systems have a great impact on their performance and lifetime.However,most of the current analyses in reviews only focus on a single system or one aspect of the technology.It is highly necessary to systematically analyze the new development and research trends of vehicular fuel cell systems.This paper proposes a quantitative and visual analysis based on bibliometrics to more intuitively reveal the research direction in this field.Key information on hydrogen/air subsystems,energy management strategies,and thermal management subsystems are analyzed by combining the literature analysis and technical discussion.In detail,the possible reasons behind the variations in the number of articles published within different periods of the subsystem are revealed.Then,through qualitative analysis of representative papers with high citations in different periods,the main research methods adopted by scholars in different periods are derived.Finally,the technology research trends of control methods that need to be addressed in the future are summarized for different subsystems.This paper provides a reference for researchers in the field to understand more clearly the current trends in the field and provide new ideas to break through the challenges of developing high-performance fuel cell systems.
基金The work was supported by the National Natural Science Foundation of China(No.92061125,22209186)Beijing Natural Science Foundation(No.Z200012)+1 种基金Jiangxi Natural Science Foundation(No.20212ACB213009,20223BBG74004)Youth Innovation Promotion Association,CAS(No.2023343)。
文摘Single-atom catalysts(SACs)attract significant attention owing to their high catalytic activity,high metal atom utilization efficiency,and well-defined and configurable active sites.However,achieving single-atom dispersion of active metals at high metal loadings remains challenging,limiting the performance of SACs in many practical applications.Herein,we provide a comprehensive review of recent methods developed for synthesizing high-loading SACs,critically exploring their advantages,limitations,and wider applicability.Additionally,we showcase the benefits of high-loading SACs in the oxygen reduction reaction(ORR),water electrolysis,photocatalytic hydrogen production and CO oxidation.Although great recent progress has been made in the synthesis of high loading SACs,simple and universal routes that allowed the preprogrammed preparation of single metal and multi-metal SACs with specific metal coordination need to be discovered.
基金This work was supported by the Beijing Natural Science Foundation(No.2202052 and Z200012)National Natural Science Foundation of China(No.92061125)+2 种基金Hebei Natural Science Foundation(B2020103043)Science and Technology Program of Inner Mongolia(2021GG0237)Key R&D Program of Henan Province(No.231111241800).
文摘Developing single-atom Fe–N_(4)/C catalysts is crucial for the large-scale implementation of proton exchange membrane fuel cells(PEMFCs).While Fe–N_(4)/C catalysts are inherently active in accelerating the slow ORR process,their performance is still inferior to that of Pt/C.Herein,a trace Co-doped Fe single-atom catalyst(Fe(tCo)–N–C)containing more active Fe_(2)N_(8) sites has been synthesized.Interestingly,compared with typical FeN4 sites in an Fe–N–C electrocatalyst,the Fe_(2)N_(8) sites generate a larger Fe–N bond length due to Co-doping.The elongated Fe–N bond in Fe_(2)N_(8) lowers the d-band center and charge density of iron sites,enhancing the ORR process by facilitating the formation of*OOH and generation and desorption of*OH.Fe(tCo)–N–C manifested excellent acidic and alkaline ORR activity,with a half-wave potential(E_(1/2))of 0.80 V in HClO_(4) solution and 0.89 V in KOH medium.More importantly,high peak power densities(Pmax)were realized by applying Fe(tCo)–N–C in PEMFCs,with the Pmax reaching 890 mW cm^(-2) in H_(2)–O_(2) and 380 mW cm^(-2) in H_(2)–air.Additionally,trace Co dopants in the catalyst improved carbon graphitization and provided high ORR catalytic stability.This research introduces an innovative approach to engineering highly active Fe_(2)N_(8) sites,providing valuable insights for the sustainable progress of PEMFC technology.
基金The work was supported by the National Natural Science Foundation of China(No.92061125,22209186)Beijing Natural Science Foundation(No.Z200012)+1 种基金Jiangxi Natural Science Foundation(No.20212ACB213009,20223BBG74004)Youth Innovation Promotion Association,CAS(No.2023343).
文摘At present,the catalysts commercially used for the oxygen reduction reaction of the cathode of proton exchange membrane fuel cells(PEMFCs)are carbon-supported platinum-based catalysts.However,the carbon supports are susceptible to corrosion under harsh working conditions,which greatly shortens the life of the catalysts.Highly stable carbon supports are urgently required for high-performance PEMFCs.In this work,we developed structure-stable and highly graphitized three-dimensional network carbon nanofibers(CNF)derived from polyaniline by heat treatment at 1200℃.The CNF-1200-based catalyst(PtNi/CNF-1200)loaded with PtNi nanoparticles showed excellent stability.After 5000 cycles from 1.0 to 1.5 V in oxygen saturated 0.1 M HClO_(4) electrolyte,the losses in the half-wave potential and mass activity were only 5 mV and 15%,respectively,far lower than those of commercial Pt/C.The high graphitization degree of CNF-1200 promotes the corrosion resistance of the catalyst.In addition,nitrogen doping effectively facilitates the catalyst–support interaction,stabilizes the highly dispersed PtNi nanoparticles,and improves the stability and activity of PtNi/CNF-1200.
