Titanium(Ti)is a promising candidate for biomedical implants due to lightweight,superior corrosion resistance and biocompatibility.Nevertheless,pure Ti is confronted with poor wear resistance which poses a profound bo...Titanium(Ti)is a promising candidate for biomedical implants due to lightweight,superior corrosion resistance and biocompatibility.Nevertheless,pure Ti is confronted with poor wear resistance which poses a profound bottleneck for orthopedic implant applications.In this work,a novel and feasible route of mechanical milling(MM)and laser powder bed fusion(LPBF)was first developed for architecting highly tunable heterostructure in pure Ti,aiming to overcome wear resistance dilemma.During MM process,a spatial core-shell heterostructure within Ti particle was triggered by manipulating gradient and intense plastic deformation,accompanied with pre-existing dislocations.In subsequent LPBF process,the highly transient-melting kinetics and localized nature effectively perpetuated grain heterogeneity,hence creating a harmonic heterostructure within consolidated pure Ti.Consequently,the heterostructured Ti exhibited an excellent enhanced wear resistance(33.7%)compared to the homogeneous counterpart,which was attributed to a marvelous strength-plasticity synergy motivated by the hetero-deformation induced strengthening and strain-hardening.Furthermore,back-stress caused by geometrical necessary dislocation pile-ups offset partial wear shear-stress,also contributing to wear resistance enhancement.This study not only provides a manoeuvrable and paradigm route to fabricate Ti with conspicuous strength-plasticity synergy and wear resistance,but also sheds light on developing and extending cutting-edge biomedical implant applications.展开更多
1.Introduction.The Ti6Al4V alloy is extensively utilized across various indus-trial sectors due to its favorable characteristics,such as lightweight design,high strength,and resistance to corrosion[1].In effort s to f...1.Introduction.The Ti6Al4V alloy is extensively utilized across various indus-trial sectors due to its favorable characteristics,such as lightweight design,high strength,and resistance to corrosion[1].In effort s to further reduce weight,functional elements like electric actuators can be substituted with intelligent materials like shape memory alloys(SMAs)[2,3].Among SMAs,NiTi alloy stands out for its sens-ing and actuation capabilities,significantly enhancing the safety and reliability of engineering structures[4,5].Integrating Ti6Al4V and NiTi alloys within a single component holds the potential to provide precise feedback on mechanical,thermal,or environmen-tal conditions[6,7].展开更多
Nickel-based alloys applied in marine environments often face multiple challenges of stress,corrosion and wear.In this work,heterostructured NiCrTi alloy was prepared by spark plasma sintering coarse Ni20Cr and ultraf...Nickel-based alloys applied in marine environments often face multiple challenges of stress,corrosion and wear.In this work,heterostructured NiCrTi alloy was prepared by spark plasma sintering coarse Ni20Cr and ultrafine Ti powders.Apart that some are dissolved into the nickel alloy,Ti powders react in situ with Ni20Cr during sintering to form hard intermetallic Ni_(3)Ti.It builds up a typical heterostructure that endows NiCrTi alloy with well-balanced mechanical strength and plasticity,e.g.high yield strength of 1321 MPa,compressive strength of 2470 MPa,and compressive strain of 20%.On tribocorrosion,the hard shell enriched with Ti transforms to connected protrusion and form in situ surface texture.Oxides or wear debris are trapped at the textured surface and compacted to form a stable tribofilm.Thus negative synergy between corrosion and wear is observed for NiCrTi and high tribocorrosion resistance is achieved.At a potential of+0.3 V,the tribocorrosion rate of NiCrTi is reduced by an order of magnitude to 1.87×10^(-5)mm^(3)/(Nm)in comparison to the alloy Ni20Cr.展开更多
Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4...Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.展开更多
Heat treatment significantly influences homogeneous material microstructures and mechanical properties,which can be improved by an optimal heat treatment process.However,heat treatment application to heterogeneous mat...Heat treatment significantly influences homogeneous material microstructures and mechanical properties,which can be improved by an optimal heat treatment process.However,heat treatment application to heterogeneous materials presents significant challenges due to compositional and microstructural heterogeneities.Herein,a laminated heterostructured alloy comprising alternating316L stainless steel(SS)and 18Ni300 maraging steel(MS)layers fabricated using wire and arc additive manufacturing was investigated.A solution treatment was applied at900℃for 0.5 h.Subsequently,the solution-treated and asfabricated(AF)samples were aged at 500℃for 4 h;these samples were denoted SA and AT,respectively.The AT phase compositions and orientations were similar to those of AF.The SA 316L SS layer resembled that of AF,but the SA 18Ni300 MS layers exhibited a reduced austenite phase fraction and refined grain size,attributable to solid-state transformation.In the AT sample,aging induced the formation of nanoscale acicularωphase and ellipsoidal Ni_(3)Ti,Fe_(2)Mo,and X precipitates in the 18Ni300 MS layers.Conversely,the SA precipitates contained acicular Fe Ni_(2)and ellipsoidalω,Ni_(3)Ti,and X precipitates,and their fractions were lower than those in AT precipitates.The18Ni300 MS layer microhardness in the heat-treated samples increased due to nanoprecipitation,but the 316L SS layer microhardness resembled that of AF.The AT and SA ultimate tensile strengths increased to(1360±50)and(1473±41)MPa,respectively,attributable to precipitation strengthening.The SA 316L SS layer exhibited a high stress-induced martensite fraction,enhancing the ductility of heated samples.展开更多
Heterogeneous metallic structures constitute a novel class of materials with excellent mechanical properties.However,the existing process for obtaining heterostructures from a single material does not meet large-scale...Heterogeneous metallic structures constitute a novel class of materials with excellent mechanical properties.However,the existing process for obtaining heterostructures from a single material does not meet large-scale industrial requirements.In this study,a pure copper heterostructured laminate(HSL)composed of a surface elongatedgrain layer and a central equiaxed-grain layer was fabricated by rolling bonding and annealing.To study the effect of the interface on the mechanical properties of gradient-structured materials,both laminate metal composite(LMC)and non-composite laminate(NCL)were fabricated by cold-rolling pretreatment of the center layer(60%reduction)and cold-rolling bonding of the whole blank(67%reduction).Then,the HSL was obtained by controlling the post-annealing regimes,the microstructure of each layer was optimized,and a larger degree of microstructural heterogeneities,such as grain size,misorientation angle,and grain orientation,was obtained,which resulted in obvious mechanical differences.Tensile tests of the HSL,surface layer,center layer,and NCL specimens revealed that the HSL annealed at 300°C for 1 h had a significantly higher strength than the center layer and a higher elongation than the surface layer.The HSL had a tensile strength and elongation at fracture of 278.08 MPa and 46.2%,respectively,indicating a good balance of strength and plasticity.The improved properties were primarily attributed to the strengthening or strain hardening due to the inhomogeneous deformation of the heterogeneous layers in the laminate and the mutual constraint acquired by the distinct layers with strong mechanical differences.The HSL had an interfacial bonding strength of 178.5 MPa,which played a vital role in the coordinated deformation of the heterogeneous layers.This study proposes an HSL design method that effectively simplifies the process of obtaining heterostructures in homogeneous materials by controlling the cumulative deformation of the surface and center layers.展开更多
Owing to the merits of high energy density,as well as clean and sustainable properties,hydrogen has been deemed to be a prominent alternative energy to traditional fossil fuels.Electrocatalytic hydrogen evolution reac...Owing to the merits of high energy density,as well as clean and sustainable properties,hydrogen has been deemed to be a prominent alternative energy to traditional fossil fuels.Electrocatalytic hydrogen evolution reaction(HER)has been considered to be mostly promising for achieving green hydrogen production,and has been widely studied in acidic and alkaline solutions.In particular,HER in alkaline media has high potential to achieve large-scale hydrogen production because of the increased durability of electrode materials.However,for the currently most prominent catalyst Pt,its HER kinetics in an alkaline solution is generally 2e3 orders lower than that occurring in an acidic solution because of the low Hþconcentration in alkaline electrolytes.Fortunately,construction of heterostructured electrocatalysts has proved to be an efficient strategy for boosting alkaline HER kinetics because of their various structural merits.The synergistic effect is a unique characteristic of heterostructures,which means that one functional active site serves as a promoter for water dissociation and another one takes a charge of moderate hydrogen adsorption,thus synergistically improving HER performance.In addition,each building block of the heterostructures is tunable,providing moreflexibility and chances to construct optimal catalysts.Furthermore,due to the presence of Fermi energy difference between the two components at the interface,the electronic structure of each component could possibly be rationally modulated,thus much enhanced HER performance in alkaline electrolyte can be ach-ieved.With a deeper understanding of on nanoscience and rapid development of nanotechnology,more sophisticated alternative designing strategies have been explored for constructing high-performance heterostructured electro-catalysts.This review presents an outline of the latest development of heterostructured catalysts toward alkaline HER and the rational design principles for constructing interfacial heterostructures to accelerate alkaline HER kinetics.The basic reaction pathways of HER in alkaline media arefirst described,and then emerging efficient strategies to promote alkaline HER kinetics,including synergistic effect,strain effect,electronic interaction,phase engineering,and ar-chitecture engineering.Finally,current existing challenges and research opportunities that deserve further investi-gation are proposed for the consideration of novel heterostructures towards practical applications.展开更多
We report a facile template-free fabrication of heterostructured Co_(3)O_(4)/CuO hollow nanospheres using pre-synthesized Co/Cu-glycerate as conformal precursor.The introduction of copper nitrate in the solvothermal r...We report a facile template-free fabrication of heterostructured Co_(3)O_(4)/CuO hollow nanospheres using pre-synthesized Co/Cu-glycerate as conformal precursor.The introduction of copper nitrate in the solvothermal reaction system of glycerol/isopropanol/cobalt nitrate readily induces the conversion from solid Co-glycerate to hollow Co/Cu-glycerate nanospheres,and the effect of the Co/Cu atomic ratio on the structure evolution of the metal glycerates as well as their corresponding oxides were investigated.When examined as anode materials for lithium-ion batteries,the well-defined Co_(3)O_(4)/CuO hollow nanospheres with Co/Cu molar ratio of 2.0 demonstrate excellent lithium storage performance,delivering a high reversible capacity of 930 mAh/g after 300 cycles at a current density of 0.5 A/g and a stable capacity of 650 mAh/g after 500 cycles even at a higher current density of 2.0 A/g,which are much better than their counterparts of bare CuO and Co_(3)O_(4).The enhanced lithium storage performance can be attributed to the synergistic effect of the CuO and Co_(3)O_(4)heterostructure with hollow spherical morphology,which greatly enhances the charge/electrolyte transfer and effectively buffers the volume changes upon lithiation/delithiation cycling.展开更多
Metals and alloys with heterogeneous microstructures are an emerging class of materials that exhibit exceptional mechanical properties,owing to the novel scientific principle of hetero-deformation induced(HDI)strength...Metals and alloys with heterogeneous microstructures are an emerging class of materials that exhibit exceptional mechanical properties,owing to the novel scientific principle of hetero-deformation induced(HDI)strengthening and hardening.For magnesium alloys,due to their low recrystallization temperature,poor ductility at room temperature,limited cold workability,and the tendency to generate strong basal texture during deformation,it is difficult to obtain heterostructures without relying on precipitation of the second phases.Here,three heterostructured Mg-2.9Y(wt.%)materials with varying accumulative equivalent true strains,i.e.,5%-5 cycles,7.5%-5 cycles,and 10%-5 cycles materials were fabricated via applying five complete triaxial compression cycles to the bulk alloy.The 5%-5 cycles material with an accumulative equivalent true strain of 0.37 is featured with long twin lamellae embedded in coarse grains.When the accumulative true strain increases to 0.72,a heterogeneous structure composed of long and short twin lamellae is formed inside the 7.5%-5 cycles material.As the equivalent true strain further increases to 1.01,the 10%-5 cycles material exhibits a mixed structure with densely refined twin lamellae embedded in the coarse-grained matrix.The room-temperature uniaxial tensile tests show that the yield strength of the materials processed by triaxial cyclic compression(TCC)has been significantly improved compared to that at the initial state,whereas ductility was not significantly sacrificed without the subsequent heat treatment.The dense and refined twin lamellae that serve as hard domains in this material provide a high density of interfaces and impede dislocation motion effectively.This results in significant HDI strengthening and hardening.These findings provide new insight into the design of heterostructured hexagonal close-packed materials with both high strength and good ductility.展开更多
Heterostructured metals and alloys are a new class of materials in which mechanical behaviors between the heterogeneous regions are significantly different,and the mechanical properties of bulk materials are superior ...Heterostructured metals and alloys are a new class of materials in which mechanical behaviors between the heterogeneous regions are significantly different,and the mechanical properties of bulk materials are superior to the superposition of individual regions.In this paper,three distinct types of heterostructures were constructed in Mg-2.77Y(wt.%)alloy by applying simple thermomechanical processing.Namely,Type I:the non-recrystallized grains of several tens of microns were embedded in the micron-scaled recrystallized grains that were distributed along shear bands and dispersed near grain boundaries;Type II:the aggregations of micron-scaled recrystallized grains were surrounded by the non-recrystallized grains;Type II:the micron-scaled recrystallized grains dominated the microstructure,and the non-recrystallized regions with diameters of tens of micrometers were surrounded by those fine recrystallized grains.Mechanical tests showed that the material with type III heterostructure had the optimal combination of yield strength and uniform elongation.This is attributed to its remarkable hetero-deformation induced(HDI)strengthening and dislocation strengthening.At the initial stage of plastic deformation(engineering strain below 4%),the rapid accumulation of geometrically necessary dislocations(GNDs)at the interfaces between recrystallized and non-recrystallized regions and between neighboring recrystallized grains lead to the significant HDI strengthening.As deformation proceeded,the HDI strengthening effect gradually decreased,and the traditional dislocation strengthening that was caused by GNDs accumulation at grain boundaries became significant.In-situ electron back-scattered diffraction(EBSD)testing revealed that the non-basal slip in the non-recrystallized regions became more remarkable in the late stage of deformation,which improved ductility and strain hardening of the alloy.These findings provide new insight into the design of high-performance hexagonal close-packed structural materials by using the concept of HDI strengthening.展开更多
Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after th...Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.展开更多
Vertically aligned TiO2/SrTiO3 core–shell heterostructured nanowire arrays with different shell thicknesses(5–40 nm)were fabricated on fluorine-doped tin oxide substrate via a hydrothermal process.Microstructural ch...Vertically aligned TiO2/SrTiO3 core–shell heterostructured nanowire arrays with different shell thicknesses(5–40 nm)were fabricated on fluorine-doped tin oxide substrate via a hydrothermal process.Microstructural characterization demonstrated that the TiO2 nanowires were uniformly coated by the singlecrystal SrTiO3 shell,where continuous and large-area interface could be clearly observed.By this means,significantly enhanced photoelectrochemical water splitting properties(0.78 mA·cm^-2 at 1.23 V vs.RHE)were successfully realized in well-designed sample(with a shell thickness of 5–10 nm)compared with those of pristine TiO2(0.38 mA·cm^-2 at 1.23 V vs.RHE).The improvement of photoelectrochemical properties was attributed to the improved charge injection and charge separation,which are calculated by the results of water oxidation and sulfite oxidation measurements.Based on these results,a mechanism was proposed that SrTiO3 shell acted as an electron–hole separation layer to improve the photocurrent density.On the other hand,the sample with an over-thick SrTiO3 shell(20–40 nm)exhibited slightly reduced photoelectrochemical properties(0.66 mA·cm^-2),which could be explained by the increase of the recombination rate in thethicker SrTiO3 shell.This work provided a facile strategy to improve and modulate the photoelectrochemical performance of heterostructured photoanodes.展开更多
A catalyst of ferroelectric-BaTiO_(3)@photoelectric-TiO_(2) nanohybrids(BaTiO_(3)@TiO_(2))with enhanced photocatalytic activity was synthesized via a hydrolysis precipitation combined with a hydrothermal approach.Comp...A catalyst of ferroelectric-BaTiO_(3)@photoelectric-TiO_(2) nanohybrids(BaTiO_(3)@TiO_(2))with enhanced photocatalytic activity was synthesized via a hydrolysis precipitation combined with a hydrothermal approach.Compared to pure TiO_(2),pure BaTiO_(3) and BaTiO_(3)/TiO_(2) physical mixture,the heterostructured BaTiO_(3)@TiO_(2) exhibits significantly improved photocatalytic activity and cycling stability in decomposing Rhodamine B(RhB)and the degradation efficiency is 1.7 times higher than pure TiO_(2) and 7.2 times higher than pure BaTiO_(3).These results are mainly attributed to the synergy effect of photoelectric TiO_(2),ferroelectric-BaTiO_(3) and the rationally designed interfacial structure.The mesoporous microstructure of TiO_(2) is of a high specific area and enables excellent photocatalytic activity.The ferroelectric polarization induced built-in electric field in BaTiO_(3) nanoparticles,and the intimate interfacial interactions at the interface of BaTiO_(3) and TiO_(2) are effective in driving the separation and transport of photogenerated charge carriers.This strategy will stimulate the design of heterostructured photocatalysts with outstanding photocatalytic performance via interface engineering.展开更多
Dispersive strain bands have been reported as a characteristic deformation feature of heterostructured materials,which helps to improve ductility.However,their formation mechanism is still not well understood.Here we ...Dispersive strain bands have been reported as a characteristic deformation feature of heterostructured materials,which helps to improve ductility.However,their formation mechanism is still not well understood.Here we report the formation of dispersed strain bands through dual-level hierarchical strain banding and its effect on the mechanical behavior of a heterostructured Fe-40Cu model material.Specifically,deformation started by the formation and propagation of dispersed microscale strain bands in the heterostructured Fe-40Cu material.High strain gradient was generated within the microscale strain bands during their propagation and was accommodated by the accumulation of geometrically necessary disloca-tions(GNDs).The dispersed microscale strain bands were not uniformly distributed,but instead grouped together to form macroscale strain bands that were uniformly distributed over the entire gage section to accommodate the majority of the applied strain.The formation of this dual-level hierarchical strain bands prevented the formation of large strain localization to fail the sample prematurely.It was also found that increasing the strain hardening capacity of soft copper zones provides more room for the accumulation of GNDs,resulting in higher constraint to microscale strain band propagation and consequently higher ductility.These observations suggest the possibility of tailoring microscale strain bands to optimize tensile performance of heterostructured materials.展开更多
To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with...To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with both the interphase properties and multi-metal synergistic effects.Herein,as a proof of concept,a delicate NiCo(OH)_(x)-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition,followed by an electrochemical etching-growth process,which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction,with an overpotential of 21 and 139 mV at 10 and 500 mA cm^(−2),respectively.Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)_(x)-Co_(y)W heteroge-neous interface resulted in favorable electron redistribution and faster electron transfer efficiency.The amorphous NiCo(OH)_(x) strengthened the water dissociation step,and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H_(2) desorption.In addition,NiCo(OH)_(x)-CoyW exhibited desirable urea oxidation reaction activity for matching H_(2) generation with a low voltage of 1.51 V at 50 mA cm^(−2).More importantly,the synthesis and testing of the NiCo(OH)_(x)-CoyW catalyst in this study were all solar-powered,sug-gesting a promising environmentally friendly process for practical applications.展开更多
The harsh melt-spinning and annealing processes of high saturation magnetization nanocrystalline softmagnetic alloys are the biggest obstacles for their industrialization. Here, we proposed a novel strategy to enlarge...The harsh melt-spinning and annealing processes of high saturation magnetization nanocrystalline softmagnetic alloys are the biggest obstacles for their industrialization. Here, we proposed a novel strategy to enlarge the processing window by annealing the partially crystallized precursor ribbons via a heterostructured crystallization process. The heterostructured evolution of Fe_(84.75)Si_(2)B_(9)P_(3)_(C0.5)Cu_(0.75)(at.%)alloy ribbons with different spinning rate were studied in detail, to demonstrate the gradient nucleation and grain refinement mechanisms. The nanocrystalline alloys made with industrially acceptable spinning rate of 25-30 m/s and normal annealing process exhibit excellent magnetic properties and fine nanostructure. The small quenched-in crystals/clusters in the free surface of the low spinning rate ribbons will not grow to coarse grains, because of the competitive grain growth and shielding effect of metalloid elements rich interlayer with a high stability. Avoiding the precipitation of quenched-in coarse grains in precursor ribbons is thus a new criterion for the composition and process design, which is more convenient than the former one with respect to the homogenous crystallization mechanism, and enable us to produce high performance nanocrystalline soft-magnetic alloys. This strategy is also suitable for improving the compositional adjustability, impurity tolerance, and enlarging the window of melt temperature,which is an important reference for the future development of composition and process.展开更多
A low-alloyed Mg-1.2Zn-0.1Ca(wt.%)alloy was fabricated via low-temperature extrusion and annealing at 250℃for different times(10,30,and 90 min)to attain heterostructures with different fine-grained fractions,focusing...A low-alloyed Mg-1.2Zn-0.1Ca(wt.%)alloy was fabricated via low-temperature extrusion and annealing at 250℃for different times(10,30,and 90 min)to attain heterostructures with different fine-grained fractions,focusing on the effect of heterostructure on the mechanical properties.Partial dynamic recrystallization(RX)occurred during extrusion at 150℃,and a lamellar structure consisting of fine RX grains and coarse unRX grains was obtained.The subsequent annealing promoted static RX in the as-extruded alloy,leading to an increased fine-grained fraction from 67%to 95%.Meanwhile,the co-segregation of Zn and Ca atoms impeded the migration of grain boundaries,thus achieving a fine grain size of 0.8–1.6μm.The sample annealed for 10 min with a fine-grained fraction of 73%and an average RX grain size of 0.9μm exhibited a superior combination of high yield strength(305 MPa)and good ductility(20%).In comparison,an excellent elongation of 30%was achieved in the alloy with a nearly fully-RXed microstructure and an average grain size of 1.6μm after 90 min annealing,despite a lower yield strength of 228 MPa.In unRX grains,the hard orientation with(01–10)parallel to the extrusion direction and high-density dislocations made it more difficult to deform compared with the RX grains,thus producing hetero-deformation induced(HDI)strengthening.Besides fine grains and high-density dislocations,HDI strengthening is the key to achieving the superior mechanical properties of the low-alloyed Mg alloy.展开更多
Retina nociceptor,as a key sensory receptor,not only enables the transport of warning signals to the human central nervous system upon its exposure to noxious stimuli,but also triggers the motor response that minimize...Retina nociceptor,as a key sensory receptor,not only enables the transport of warning signals to the human central nervous system upon its exposure to noxious stimuli,but also triggers the motor response that minimizes potential sensitization.In this study,the capability of two-dimensional all-oxide-heterostructured artificial nociceptor as a single device with tunable properties was confirmed.Newly designed nociceptors utilize ultra-thin sub-stoichiometric TiO2–Ga2O3 heterostructures,where the thermally annealed Ga2O3 films play the role of charge transfer controlling component.It is discovered that the phase transformation in Ga2O3 is accompanied by substantial jump in conductivity,induced by thermally assisted internal redox reaction of Ga2O3 nanostructure during annealing.It is also experimentally confirmed that the charge transfer in alloxide heterostructures can be tuned and controlled by the heterointerfaces manipulation.Results demonstrate that the engineering of heterointerfaces of two-dimensional(2D)films enables the fabrication of either high-sensitive TiO2–Ga2O3(Ar)or high-threshold TiO2–Ga2O3(N2)nociceptors.The hypersensitive nociceptor mimics the functionalities of corneal nociceptors of human eye,whereas the delayed reaction of nociceptor is similar to high-threshold nociceptive characteristics of human sensory system.The long-term stability of 2D nociceptors demonstrates the capability of heterointerfaces engineering for e ective control of charge transfer at 2D heterostructured devices.展开更多
Metal-organic frameworks(MOFs) with high designability and structure diversity have been widely developed as promising photocatalytic materials,but most of them suffer from poor charge transportation and separation ef...Metal-organic frameworks(MOFs) with high designability and structure diversity have been widely developed as promising photocatalytic materials,but most of them suffer from poor charge transportation and separation efficiency.To address it,the construction of MOFs-based heterostructures has been thus highly inspired.In this minireview,we will first introduce the basic principles of photocata lytic water splitting and heterostructure systems,and then discuss state-of-the-art MOFs-based heterostructures for photocata lytic water splitting to produce hydrogen.Meanwhile,special attention will be paid to the key factors affecting the interfacial charge transfer of heterostructures,such as interface connection mode,morphology control,and modification.Eventually,the challenges and prospects faced by the construction of high-efficiency MOFs-based heterostructure water slitting photocatalysts are proposed.展开更多
Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activi...Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activity, selectivity and stability. In this work, a facile PdII-complex pyrolysis method is applied to synthesize the high-quality one-dimensional heterostructured Pd/Pd O nanowires(Pd/Pd O H-NWs).The as-prepared Pd/Pd O H-NWs have a large electrochemically active surface area, abundant defects and Pd/Pd O heterostructure. Electrochemical measurement results reveal that Pd/Pd O H-NWs exhibit up to 94% CO Faraday efficiency with a current density of 11.6 m A cm^(-2) at an applied potential of -0.8 V. Meanwhile, Pd/Pd O H-NWs can achieve a stable catalytic process of 12 h for CO_(2) ER. Such outstanding CO_(2) ER performance of Pd/Pd O H-NWs has also been verified in the flow cell test. The density functional theory calculations indicate that Pd/Pd O heterostructure can significantly weaken the CO adsorption on Pd sites, which improves the CO tolerance and consequently enhances the catalytic performance of Pd/Pd O H-NWs for CO_(2) ER. This work highlights a facile complex pyrolysis strategy for the synthesis of Pd-based CO_(2) ER catalysts and provides a new application instance of metal/metal oxide heterostructure in electrocatalysis.展开更多
基金National Key Research and Development Program of China (2023YFB4605800)Hunan Provincial Natural Science Foundation of China (2025JJ30015)+6 种基金The Natural Science Foundation of China (U24A20120,52475362,52275395)The Science and Technology Innovation Program of Hunan Province(2023RC3046)Young Elite Scientists Sponsorship Program by CAST(2020QNRC002)Central South University Innovation-Driven Research Programme (2023CXQD023)JiangXi Provincial Natural Science Foundation of China (20224ACB204013)The Project of State Key Laboratory of Precision Manufacturing for Extreme Service Performance,Central South UniversityThe Fundamental Research Funds for the Central Universities of Central South University (CX20240012)
文摘Titanium(Ti)is a promising candidate for biomedical implants due to lightweight,superior corrosion resistance and biocompatibility.Nevertheless,pure Ti is confronted with poor wear resistance which poses a profound bottleneck for orthopedic implant applications.In this work,a novel and feasible route of mechanical milling(MM)and laser powder bed fusion(LPBF)was first developed for architecting highly tunable heterostructure in pure Ti,aiming to overcome wear resistance dilemma.During MM process,a spatial core-shell heterostructure within Ti particle was triggered by manipulating gradient and intense plastic deformation,accompanied with pre-existing dislocations.In subsequent LPBF process,the highly transient-melting kinetics and localized nature effectively perpetuated grain heterogeneity,hence creating a harmonic heterostructure within consolidated pure Ti.Consequently,the heterostructured Ti exhibited an excellent enhanced wear resistance(33.7%)compared to the homogeneous counterpart,which was attributed to a marvelous strength-plasticity synergy motivated by the hetero-deformation induced strengthening and strain-hardening.Furthermore,back-stress caused by geometrical necessary dislocation pile-ups offset partial wear shear-stress,also contributing to wear resistance enhancement.This study not only provides a manoeuvrable and paradigm route to fabricate Ti with conspicuous strength-plasticity synergy and wear resistance,but also sheds light on developing and extending cutting-edge biomedical implant applications.
基金supported by the National Natural Science Foundation of China(Grant No.52235006)the National Key Research and Development Program of China(Grant No.2022YFB4600500)+3 种基金the National Natural Science Foundation of China(Grant Nos.52025053 and 52105303)the Natural Science Foundation of Jilin Province(Grant No.20220101209JC)the Postdoctoral Fellow-ship Program of CPSF(Grant GZC20240587 and GZC20230944)the Graduate Innovation Fund of Jilin University(2024CX063).
文摘1.Introduction.The Ti6Al4V alloy is extensively utilized across various indus-trial sectors due to its favorable characteristics,such as lightweight design,high strength,and resistance to corrosion[1].In effort s to further reduce weight,functional elements like electric actuators can be substituted with intelligent materials like shape memory alloys(SMAs)[2,3].Among SMAs,NiTi alloy stands out for its sens-ing and actuation capabilities,significantly enhancing the safety and reliability of engineering structures[4,5].Integrating Ti6Al4V and NiTi alloys within a single component holds the potential to provide precise feedback on mechanical,thermal,or environmen-tal conditions[6,7].
基金financially supported by the Liaoning Revitalization Talents Program(No.XLYC2203133)the Fundamental Research Funds for the Central Universities(No.N2302018)the Ningbo Yuyao City Science and Technology Plan Project(No.2023J03010010).
文摘Nickel-based alloys applied in marine environments often face multiple challenges of stress,corrosion and wear.In this work,heterostructured NiCrTi alloy was prepared by spark plasma sintering coarse Ni20Cr and ultrafine Ti powders.Apart that some are dissolved into the nickel alloy,Ti powders react in situ with Ni20Cr during sintering to form hard intermetallic Ni_(3)Ti.It builds up a typical heterostructure that endows NiCrTi alloy with well-balanced mechanical strength and plasticity,e.g.high yield strength of 1321 MPa,compressive strength of 2470 MPa,and compressive strain of 20%.On tribocorrosion,the hard shell enriched with Ti transforms to connected protrusion and form in situ surface texture.Oxides or wear debris are trapped at the textured surface and compacted to form a stable tribofilm.Thus negative synergy between corrosion and wear is observed for NiCrTi and high tribocorrosion resistance is achieved.At a potential of+0.3 V,the tribocorrosion rate of NiCrTi is reduced by an order of magnitude to 1.87×10^(-5)mm^(3)/(Nm)in comparison to the alloy Ni20Cr.
基金the financial support from the Key Research and Development Program sponsored by the Ministry of Science and Technology(MOST)(2022YFB4002000,2022YFA1203400)the National Natural Science Foundation of China(22102172,22072145,22372155,22005294,21925205,21721003)。
文摘Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.
基金supported by the National Natural Science Foundation of China(No.52301050)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(No.2022QNRC001the China Postdoctoral Science Foundation(No.2023M741701)。
文摘Heat treatment significantly influences homogeneous material microstructures and mechanical properties,which can be improved by an optimal heat treatment process.However,heat treatment application to heterogeneous materials presents significant challenges due to compositional and microstructural heterogeneities.Herein,a laminated heterostructured alloy comprising alternating316L stainless steel(SS)and 18Ni300 maraging steel(MS)layers fabricated using wire and arc additive manufacturing was investigated.A solution treatment was applied at900℃for 0.5 h.Subsequently,the solution-treated and asfabricated(AF)samples were aged at 500℃for 4 h;these samples were denoted SA and AT,respectively.The AT phase compositions and orientations were similar to those of AF.The SA 316L SS layer resembled that of AF,but the SA 18Ni300 MS layers exhibited a reduced austenite phase fraction and refined grain size,attributable to solid-state transformation.In the AT sample,aging induced the formation of nanoscale acicularωphase and ellipsoidal Ni_(3)Ti,Fe_(2)Mo,and X precipitates in the 18Ni300 MS layers.Conversely,the SA precipitates contained acicular Fe Ni_(2)and ellipsoidalω,Ni_(3)Ti,and X precipitates,and their fractions were lower than those in AT precipitates.The18Ni300 MS layer microhardness in the heat-treated samples increased due to nanoprecipitation,but the 316L SS layer microhardness resembled that of AF.The AT and SA ultimate tensile strengths increased to(1360±50)and(1473±41)MPa,respectively,attributable to precipitation strengthening.The SA 316L SS layer exhibited a high stress-induced martensite fraction,enhancing the ductility of heated samples.
基金Supported by National Key Research and Development Program of China(Grant No.2018YFA0707300)General Program of National Natural Science Foundation of China(Grant No.51905372)Postdoctoral Science Foundation of China(Grant No.2020T130463)。
文摘Heterogeneous metallic structures constitute a novel class of materials with excellent mechanical properties.However,the existing process for obtaining heterostructures from a single material does not meet large-scale industrial requirements.In this study,a pure copper heterostructured laminate(HSL)composed of a surface elongatedgrain layer and a central equiaxed-grain layer was fabricated by rolling bonding and annealing.To study the effect of the interface on the mechanical properties of gradient-structured materials,both laminate metal composite(LMC)and non-composite laminate(NCL)were fabricated by cold-rolling pretreatment of the center layer(60%reduction)and cold-rolling bonding of the whole blank(67%reduction).Then,the HSL was obtained by controlling the post-annealing regimes,the microstructure of each layer was optimized,and a larger degree of microstructural heterogeneities,such as grain size,misorientation angle,and grain orientation,was obtained,which resulted in obvious mechanical differences.Tensile tests of the HSL,surface layer,center layer,and NCL specimens revealed that the HSL annealed at 300°C for 1 h had a significantly higher strength than the center layer and a higher elongation than the surface layer.The HSL had a tensile strength and elongation at fracture of 278.08 MPa and 46.2%,respectively,indicating a good balance of strength and plasticity.The improved properties were primarily attributed to the strengthening or strain hardening due to the inhomogeneous deformation of the heterogeneous layers in the laminate and the mutual constraint acquired by the distinct layers with strong mechanical differences.The HSL had an interfacial bonding strength of 178.5 MPa,which played a vital role in the coordinated deformation of the heterogeneous layers.This study proposes an HSL design method that effectively simplifies the process of obtaining heterostructures in homogeneous materials by controlling the cumulative deformation of the surface and center layers.
基金supported by the National Natural Science Foundation of China(No.22179098)。
文摘Owing to the merits of high energy density,as well as clean and sustainable properties,hydrogen has been deemed to be a prominent alternative energy to traditional fossil fuels.Electrocatalytic hydrogen evolution reaction(HER)has been considered to be mostly promising for achieving green hydrogen production,and has been widely studied in acidic and alkaline solutions.In particular,HER in alkaline media has high potential to achieve large-scale hydrogen production because of the increased durability of electrode materials.However,for the currently most prominent catalyst Pt,its HER kinetics in an alkaline solution is generally 2e3 orders lower than that occurring in an acidic solution because of the low Hþconcentration in alkaline electrolytes.Fortunately,construction of heterostructured electrocatalysts has proved to be an efficient strategy for boosting alkaline HER kinetics because of their various structural merits.The synergistic effect is a unique characteristic of heterostructures,which means that one functional active site serves as a promoter for water dissociation and another one takes a charge of moderate hydrogen adsorption,thus synergistically improving HER performance.In addition,each building block of the heterostructures is tunable,providing moreflexibility and chances to construct optimal catalysts.Furthermore,due to the presence of Fermi energy difference between the two components at the interface,the electronic structure of each component could possibly be rationally modulated,thus much enhanced HER performance in alkaline electrolyte can be ach-ieved.With a deeper understanding of on nanoscience and rapid development of nanotechnology,more sophisticated alternative designing strategies have been explored for constructing high-performance heterostructured electro-catalysts.This review presents an outline of the latest development of heterostructured catalysts toward alkaline HER and the rational design principles for constructing interfacial heterostructures to accelerate alkaline HER kinetics.The basic reaction pathways of HER in alkaline media arefirst described,and then emerging efficient strategies to promote alkaline HER kinetics,including synergistic effect,strain effect,electronic interaction,phase engineering,and ar-chitecture engineering.Finally,current existing challenges and research opportunities that deserve further investi-gation are proposed for the consideration of novel heterostructures towards practical applications.
基金supported by the National Natural Science Foundation of China(No.52077175).
文摘We report a facile template-free fabrication of heterostructured Co_(3)O_(4)/CuO hollow nanospheres using pre-synthesized Co/Cu-glycerate as conformal precursor.The introduction of copper nitrate in the solvothermal reaction system of glycerol/isopropanol/cobalt nitrate readily induces the conversion from solid Co-glycerate to hollow Co/Cu-glycerate nanospheres,and the effect of the Co/Cu atomic ratio on the structure evolution of the metal glycerates as well as their corresponding oxides were investigated.When examined as anode materials for lithium-ion batteries,the well-defined Co_(3)O_(4)/CuO hollow nanospheres with Co/Cu molar ratio of 2.0 demonstrate excellent lithium storage performance,delivering a high reversible capacity of 930 mAh/g after 300 cycles at a current density of 0.5 A/g and a stable capacity of 650 mAh/g after 500 cycles even at a higher current density of 2.0 A/g,which are much better than their counterparts of bare CuO and Co_(3)O_(4).The enhanced lithium storage performance can be attributed to the synergistic effect of the CuO and Co_(3)O_(4)heterostructure with hollow spherical morphology,which greatly enhances the charge/electrolyte transfer and effectively buffers the volume changes upon lithiation/delithiation cycling.
基金fundings supported by the National Key Research and Development Program of China(No.2021YFA1200203)the National Natural Science Foundation of China(Nos.52371097,52301136,51922026,and 52071068)。
文摘Metals and alloys with heterogeneous microstructures are an emerging class of materials that exhibit exceptional mechanical properties,owing to the novel scientific principle of hetero-deformation induced(HDI)strengthening and hardening.For magnesium alloys,due to their low recrystallization temperature,poor ductility at room temperature,limited cold workability,and the tendency to generate strong basal texture during deformation,it is difficult to obtain heterostructures without relying on precipitation of the second phases.Here,three heterostructured Mg-2.9Y(wt.%)materials with varying accumulative equivalent true strains,i.e.,5%-5 cycles,7.5%-5 cycles,and 10%-5 cycles materials were fabricated via applying five complete triaxial compression cycles to the bulk alloy.The 5%-5 cycles material with an accumulative equivalent true strain of 0.37 is featured with long twin lamellae embedded in coarse grains.When the accumulative true strain increases to 0.72,a heterogeneous structure composed of long and short twin lamellae is formed inside the 7.5%-5 cycles material.As the equivalent true strain further increases to 1.01,the 10%-5 cycles material exhibits a mixed structure with densely refined twin lamellae embedded in the coarse-grained matrix.The room-temperature uniaxial tensile tests show that the yield strength of the materials processed by triaxial cyclic compression(TCC)has been significantly improved compared to that at the initial state,whereas ductility was not significantly sacrificed without the subsequent heat treatment.The dense and refined twin lamellae that serve as hard domains in this material provide a high density of interfaces and impede dislocation motion effectively.This results in significant HDI strengthening and hardening.These findings provide new insight into the design of heterostructured hexagonal close-packed materials with both high strength and good ductility.
基金funding from the National Natural Science Foundation of China(No.51922026)the Fundamental Research Funds for the Central Universities(Nos.N2002005,N2007011)the 111 Project(No.B20029).
文摘Heterostructured metals and alloys are a new class of materials in which mechanical behaviors between the heterogeneous regions are significantly different,and the mechanical properties of bulk materials are superior to the superposition of individual regions.In this paper,three distinct types of heterostructures were constructed in Mg-2.77Y(wt.%)alloy by applying simple thermomechanical processing.Namely,Type I:the non-recrystallized grains of several tens of microns were embedded in the micron-scaled recrystallized grains that were distributed along shear bands and dispersed near grain boundaries;Type II:the aggregations of micron-scaled recrystallized grains were surrounded by the non-recrystallized grains;Type II:the micron-scaled recrystallized grains dominated the microstructure,and the non-recrystallized regions with diameters of tens of micrometers were surrounded by those fine recrystallized grains.Mechanical tests showed that the material with type III heterostructure had the optimal combination of yield strength and uniform elongation.This is attributed to its remarkable hetero-deformation induced(HDI)strengthening and dislocation strengthening.At the initial stage of plastic deformation(engineering strain below 4%),the rapid accumulation of geometrically necessary dislocations(GNDs)at the interfaces between recrystallized and non-recrystallized regions and between neighboring recrystallized grains lead to the significant HDI strengthening.As deformation proceeded,the HDI strengthening effect gradually decreased,and the traditional dislocation strengthening that was caused by GNDs accumulation at grain boundaries became significant.In-situ electron back-scattered diffraction(EBSD)testing revealed that the non-basal slip in the non-recrystallized regions became more remarkable in the late stage of deformation,which improved ductility and strain hardening of the alloy.These findings provide new insight into the design of high-performance hexagonal close-packed structural materials by using the concept of HDI strengthening.
基金supported by the National Key Research and Development Project (2016YFC0204702)the National Natural Science Foundation of China (51478070, 21501016, 51108487)+2 种基金the Innovative Research Team of Chongqing (CXTDG201602014)the Natural Science Foundation of Chongqing (cstc2016jcyjA0481)Youth Innovation Promotion Association of Chinese Academy of Sciences (2015316)~~
文摘Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.
基金financially supported by the National Natural Science Foundation of China (Nos. 51232006, 51472218 and 11474249)the National Basic Research Program of China (No. 2015CB654900)
文摘Vertically aligned TiO2/SrTiO3 core–shell heterostructured nanowire arrays with different shell thicknesses(5–40 nm)were fabricated on fluorine-doped tin oxide substrate via a hydrothermal process.Microstructural characterization demonstrated that the TiO2 nanowires were uniformly coated by the singlecrystal SrTiO3 shell,where continuous and large-area interface could be clearly observed.By this means,significantly enhanced photoelectrochemical water splitting properties(0.78 mA·cm^-2 at 1.23 V vs.RHE)were successfully realized in well-designed sample(with a shell thickness of 5–10 nm)compared with those of pristine TiO2(0.38 mA·cm^-2 at 1.23 V vs.RHE).The improvement of photoelectrochemical properties was attributed to the improved charge injection and charge separation,which are calculated by the results of water oxidation and sulfite oxidation measurements.Based on these results,a mechanism was proposed that SrTiO3 shell acted as an electron–hole separation layer to improve the photocurrent density.On the other hand,the sample with an over-thick SrTiO3 shell(20–40 nm)exhibited slightly reduced photoelectrochemical properties(0.66 mA·cm^-2),which could be explained by the increase of the recombination rate in thethicker SrTiO3 shell.This work provided a facile strategy to improve and modulate the photoelectrochemical performance of heterostructured photoanodes.
基金Project(cstc2020jcyj-msxm X0930) supported by the Natural Science Foundation of Chongqing,ChinaProject(KJQN201901522) supported by Technological Research Program of Chongqing Municipal Education Commission,ChinaProject(cx2020068) supported by the Venture&Innovation Support Program for Chongqing Overseas Returnees,China。
文摘A catalyst of ferroelectric-BaTiO_(3)@photoelectric-TiO_(2) nanohybrids(BaTiO_(3)@TiO_(2))with enhanced photocatalytic activity was synthesized via a hydrolysis precipitation combined with a hydrothermal approach.Compared to pure TiO_(2),pure BaTiO_(3) and BaTiO_(3)/TiO_(2) physical mixture,the heterostructured BaTiO_(3)@TiO_(2) exhibits significantly improved photocatalytic activity and cycling stability in decomposing Rhodamine B(RhB)and the degradation efficiency is 1.7 times higher than pure TiO_(2) and 7.2 times higher than pure BaTiO_(3).These results are mainly attributed to the synergy effect of photoelectric TiO_(2),ferroelectric-BaTiO_(3) and the rationally designed interfacial structure.The mesoporous microstructure of TiO_(2) is of a high specific area and enables excellent photocatalytic activity.The ferroelectric polarization induced built-in electric field in BaTiO_(3) nanoparticles,and the intimate interfacial interactions at the interface of BaTiO_(3) and TiO_(2) are effective in driving the separation and transport of photogenerated charge carriers.This strategy will stimulate the design of heterostructured photocatalysts with outstanding photocatalytic performance via interface engineering.
基金Y.T.Zhu acknowledges the support of the National Key R&D Program of China(Grant No.2021YFA1200202)the National Natural Science Foundation of China(Grant No.51931003)the Hong Kong Research Grants Council(Grant No.GRF 11214121)。
文摘Dispersive strain bands have been reported as a characteristic deformation feature of heterostructured materials,which helps to improve ductility.However,their formation mechanism is still not well understood.Here we report the formation of dispersed strain bands through dual-level hierarchical strain banding and its effect on the mechanical behavior of a heterostructured Fe-40Cu model material.Specifically,deformation started by the formation and propagation of dispersed microscale strain bands in the heterostructured Fe-40Cu material.High strain gradient was generated within the microscale strain bands during their propagation and was accommodated by the accumulation of geometrically necessary disloca-tions(GNDs).The dispersed microscale strain bands were not uniformly distributed,but instead grouped together to form macroscale strain bands that were uniformly distributed over the entire gage section to accommodate the majority of the applied strain.The formation of this dual-level hierarchical strain bands prevented the formation of large strain localization to fail the sample prematurely.It was also found that increasing the strain hardening capacity of soft copper zones provides more room for the accumulation of GNDs,resulting in higher constraint to microscale strain band propagation and consequently higher ductility.These observations suggest the possibility of tailoring microscale strain bands to optimize tensile performance of heterostructured materials.
基金This work was financially supported by the National Natural Science Foundations of China(21878061).
文摘To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with both the interphase properties and multi-metal synergistic effects.Herein,as a proof of concept,a delicate NiCo(OH)_(x)-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition,followed by an electrochemical etching-growth process,which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction,with an overpotential of 21 and 139 mV at 10 and 500 mA cm^(−2),respectively.Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)_(x)-Co_(y)W heteroge-neous interface resulted in favorable electron redistribution and faster electron transfer efficiency.The amorphous NiCo(OH)_(x) strengthened the water dissociation step,and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H_(2) desorption.In addition,NiCo(OH)_(x)-CoyW exhibited desirable urea oxidation reaction activity for matching H_(2) generation with a low voltage of 1.51 V at 50 mA cm^(−2).More importantly,the synthesis and testing of the NiCo(OH)_(x)-CoyW catalyst in this study were all solar-powered,sug-gesting a promising environmentally friendly process for practical applications.
基金supported financially by the National Key Research and Development Program of China (No.2016YFB0300501)the National Natural Science Foundation of China (Nos.51771159,51774217,51801224,51971186)+3 种基金the Zhejiang Provincial Natural Science Foundation (No.LQ18E010006)the Ningbo Major Special Projects of the Plan"Science and Technology Innovation 2025"(No.2018B10084)financial support from general research fund (GRF)the Hong Kong Government,through the general research fund (GRF,Nos.CityU11200719,CityU11213118 and CityU11209317)。
文摘The harsh melt-spinning and annealing processes of high saturation magnetization nanocrystalline softmagnetic alloys are the biggest obstacles for their industrialization. Here, we proposed a novel strategy to enlarge the processing window by annealing the partially crystallized precursor ribbons via a heterostructured crystallization process. The heterostructured evolution of Fe_(84.75)Si_(2)B_(9)P_(3)_(C0.5)Cu_(0.75)(at.%)alloy ribbons with different spinning rate were studied in detail, to demonstrate the gradient nucleation and grain refinement mechanisms. The nanocrystalline alloys made with industrially acceptable spinning rate of 25-30 m/s and normal annealing process exhibit excellent magnetic properties and fine nanostructure. The small quenched-in crystals/clusters in the free surface of the low spinning rate ribbons will not grow to coarse grains, because of the competitive grain growth and shielding effect of metalloid elements rich interlayer with a high stability. Avoiding the precipitation of quenched-in coarse grains in precursor ribbons is thus a new criterion for the composition and process design, which is more convenient than the former one with respect to the homogenous crystallization mechanism, and enable us to produce high performance nanocrystalline soft-magnetic alloys. This strategy is also suitable for improving the compositional adjustability, impurity tolerance, and enlarging the window of melt temperature,which is an important reference for the future development of composition and process.
基金the Key-Area Research and Development Program of Guangdong Province(No.2020B010186002)the Natural Science Foundation of Guangdong for Research Team(No.2015A030312003)。
文摘A low-alloyed Mg-1.2Zn-0.1Ca(wt.%)alloy was fabricated via low-temperature extrusion and annealing at 250℃for different times(10,30,and 90 min)to attain heterostructures with different fine-grained fractions,focusing on the effect of heterostructure on the mechanical properties.Partial dynamic recrystallization(RX)occurred during extrusion at 150℃,and a lamellar structure consisting of fine RX grains and coarse unRX grains was obtained.The subsequent annealing promoted static RX in the as-extruded alloy,leading to an increased fine-grained fraction from 67%to 95%.Meanwhile,the co-segregation of Zn and Ca atoms impeded the migration of grain boundaries,thus achieving a fine grain size of 0.8–1.6μm.The sample annealed for 10 min with a fine-grained fraction of 73%and an average RX grain size of 0.9μm exhibited a superior combination of high yield strength(305 MPa)and good ductility(20%).In comparison,an excellent elongation of 30%was achieved in the alloy with a nearly fully-RXed microstructure and an average grain size of 1.6μm after 90 min annealing,despite a lower yield strength of 228 MPa.In unRX grains,the hard orientation with(01–10)parallel to the extrusion direction and high-density dislocations made it more difficult to deform compared with the RX grains,thus producing hetero-deformation induced(HDI)strengthening.Besides fine grains and high-density dislocations,HDI strengthening is the key to achieving the superior mechanical properties of the low-alloyed Mg alloy.
基金supported by Research and Development Program of the Ghent University Global Campus,South Korea.
文摘Retina nociceptor,as a key sensory receptor,not only enables the transport of warning signals to the human central nervous system upon its exposure to noxious stimuli,but also triggers the motor response that minimizes potential sensitization.In this study,the capability of two-dimensional all-oxide-heterostructured artificial nociceptor as a single device with tunable properties was confirmed.Newly designed nociceptors utilize ultra-thin sub-stoichiometric TiO2–Ga2O3 heterostructures,where the thermally annealed Ga2O3 films play the role of charge transfer controlling component.It is discovered that the phase transformation in Ga2O3 is accompanied by substantial jump in conductivity,induced by thermally assisted internal redox reaction of Ga2O3 nanostructure during annealing.It is also experimentally confirmed that the charge transfer in alloxide heterostructures can be tuned and controlled by the heterointerfaces manipulation.Results demonstrate that the engineering of heterointerfaces of two-dimensional(2D)films enables the fabrication of either high-sensitive TiO2–Ga2O3(Ar)or high-threshold TiO2–Ga2O3(N2)nociceptors.The hypersensitive nociceptor mimics the functionalities of corneal nociceptors of human eye,whereas the delayed reaction of nociceptor is similar to high-threshold nociceptive characteristics of human sensory system.The long-term stability of 2D nociceptors demonstrates the capability of heterointerfaces engineering for e ective control of charge transfer at 2D heterostructured devices.
基金supported by the National Natural Science Foundation of China(21633009,21925206,21901240)the Dalian National Laboratory for Clean Energy(DNL)Cooperation Fund,CAS(no.DNL 201913)+3 种基金DICP&QIBEBT(UN201805)International Partnership Program of Chinese Academy of Sciences(121421KYSB20190025)the DICP foundation of innovative research(DICP I201927)the support from Liao Ning Revitalization Talents Program(XLYC1807241)。
文摘Metal-organic frameworks(MOFs) with high designability and structure diversity have been widely developed as promising photocatalytic materials,but most of them suffer from poor charge transportation and separation efficiency.To address it,the construction of MOFs-based heterostructures has been thus highly inspired.In this minireview,we will first introduce the basic principles of photocata lytic water splitting and heterostructure systems,and then discuss state-of-the-art MOFs-based heterostructures for photocata lytic water splitting to produce hydrogen.Meanwhile,special attention will be paid to the key factors affecting the interfacial charge transfer of heterostructures,such as interface connection mode,morphology control,and modification.Eventually,the challenges and prospects faced by the construction of high-efficiency MOFs-based heterostructure water slitting photocatalysts are proposed.
基金supported by the National Natural Science Foundation of China(51873100)Natural Science Foundation of Shaanxi Province(2020JZ-23)+2 种基金the Fundamental Research Funds for the Central Universities(GK202101005 and 2021CBLZ004)the Innovation Team Project for Graduate Student at Shaanxi Normal University(TD2020048Y)the 111 Project(B14041)。
文摘Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activity, selectivity and stability. In this work, a facile PdII-complex pyrolysis method is applied to synthesize the high-quality one-dimensional heterostructured Pd/Pd O nanowires(Pd/Pd O H-NWs).The as-prepared Pd/Pd O H-NWs have a large electrochemically active surface area, abundant defects and Pd/Pd O heterostructure. Electrochemical measurement results reveal that Pd/Pd O H-NWs exhibit up to 94% CO Faraday efficiency with a current density of 11.6 m A cm^(-2) at an applied potential of -0.8 V. Meanwhile, Pd/Pd O H-NWs can achieve a stable catalytic process of 12 h for CO_(2) ER. Such outstanding CO_(2) ER performance of Pd/Pd O H-NWs has also been verified in the flow cell test. The density functional theory calculations indicate that Pd/Pd O heterostructure can significantly weaken the CO adsorption on Pd sites, which improves the CO tolerance and consequently enhances the catalytic performance of Pd/Pd O H-NWs for CO_(2) ER. This work highlights a facile complex pyrolysis strategy for the synthesis of Pd-based CO_(2) ER catalysts and provides a new application instance of metal/metal oxide heterostructure in electrocatalysis.
