As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM c...As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM cells based on conventional silicon-based devices suffer from structural complexity and large footprintlimitations. Here, we demonstrate an ultrafast nonvolatile TCAM cell based on the MoTe2/hBN/multilayergraphene (MLG) van der Waals heterostructure using a top-gated partial floating-gate field-effect transistor(PFGFET) architecture. Based on its ambipolar transport properties, the carrier type in the source/drain andcentral channel regions of the MoTe2 channel can be efficiently tuned by the control gate and top gate, respectively,enabling the reconfigurable operation of the device in either memory or FET mode. When working inthe memory mode, it achieves an ultrafast 60 ns programming/erase speed with a current on-off ratio of ∼105,excellent retention capability, and robust endurance. When serving as a reconfigurable transistor, unipolar p-typeand n-type FETs are obtained by adopting ultrafast 60 ns control-gate voltage pulses with different polarities.The monolithic integration of memory and logic within a single device enables the content-addressable memory(CAM) functionality. Finally, by integrating two PFGFETs in parallel, a TCAM cell with a high current ratioof ∼10^(5) between the match and mismatch states is achieved without requiring additional peripheral circuitry.These results provide a promising route for the design of high-performance TCAM devices for future in-memorycomputing applications.展开更多
In recent years,research focusing on synaptic device based on phototransistors has provided a new method for asso-ciative learning and neuromorphic computing.A TiO_(2)/AlGaN/GaN heterostructure-based synaptic phototra...In recent years,research focusing on synaptic device based on phototransistors has provided a new method for asso-ciative learning and neuromorphic computing.A TiO_(2)/AlGaN/GaN heterostructure-based synaptic phototransistor is fabricated and measured,integrating a TiO_(2)nanolayer gate and a two-dimensional electron gas(2DEG)channel to mimic the synaptic weight and the synaptic cleft,respectively.The maximum drain to source current is 10 nA,while the device is driven at a reverse bias not exceeding-2.5 V.A excitatory postsynaptic current(EPSC)of 200 nA can be triggered by a 365 nm UVA light spike with the duration of 1 s at light intensity of 1.35μW·cm^(-2).Multiple synaptic neuromorphic functions,including EPSC,short-term/long-term plasticity(STP/LTP)and paried-pulse facilitation(PPF),are effectively mimicked by our GaN-based het-erostructure synaptic device.In the typical Pavlov’s dog experiment,we demonstrate that the device can achieve"retraining"process to extend memory time through enhancing the intensity of synaptic weight,which is similar to the working mecha-nism of human brain.展开更多
This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composi...This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composite featuring particle-rare coarse grain (CG) and particle-rich fine grain (FG) zones was successfully fabricated. Experimental results demonstrated that compared with the homogeneous structure, the dual-heterostructure composite achieved a significant increase in elongation by 116 % and a remarkable 165 % improvement in the strength-ductility product (SDP), while maintaining a high ultimate tensile strength (UTS) of 417±4 MPa. This substantial performance enhancement is primarily attributed to the additional strain hardening induced by hetero-deformation-induced (HDI) strain hardening and crack-blunting capabilities, as elucidated by microstructural characterization and crystal plasticity finite element modeling (CPFEM). Notably, the strain hardening contribution from the CG zones at the early stage of deformation (≤ 45 % of total plastic deformation amount) is minimal but increases significantly during the subsequent deformation stages. The dislocation increment rate in CG zones (219 %) is observed to be more than double that in FG zones (95 %), attributed to the large grain size and low dislocation density in CG zones, which provide more space for dislocation storage. In addition, the aggravated deformation inhomogeneity as deformation progresses leads to an increase in geometrically necessary dislocations (GNDs) generation near the heterogeneous interface, thereby enhancing HDI hardening. Fracture mechanism analysis indicated that the cracks mainly initiate in the FG region and are effectively blunted upon their propagation to the CG region, necessitating increased energy consumption and indicating higher fracture toughness for the dual-heterostructure composites. This study validates the effectiveness of the dual-heterostructure design in magnesium-based composites, providing a novel understanding of the deformation mechanism through both experimental analysis and CPFEM, paving the way for the development of high-performance, lightweight structural materials.展开更多
Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal condu...Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.展开更多
In this work,we studied the persistent photoconductivity(PPC)spectra in single HgTe/CdHgTe quantum wells with different growth parameters and different types of dark conductivity.The studies were performed in a wide r...In this work,we studied the persistent photoconductivity(PPC)spectra in single HgTe/CdHgTe quantum wells with different growth parameters and different types of dark conductivity.The studies were performed in a wide radiation quantum energy range of 0.62–3.1 eV both at T=4.2 K and at T=77 K.Common features of the PPC spectra for all structures were revealed,and their relation to the presence of a CdTe cap layer in all structures and the appropriate cadmium fraction in the CdHgTe barrier layers was shown.One of the features was associated with the presence of a deep level in the CdTe layer.In addition,the oscillatory behavior of the PPC spectra in the region from 0.8–1.1 eV to 1.2–1.5 eV was observed.It is associated with the cascade emission of longitudinal optical phonons in CdHgTe barrier.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
Nanostructure engineering and composition rationalization are crucial for materials to become candidates for high-performance supercapacitor.Herein,a novel core-shell heterostructured electrode,combining CoS hollow na...Nanostructure engineering and composition rationalization are crucial for materials to become candidates for high-performance supercapacitor.Herein,a novel core-shell heterostructured electrode,combining CoS hollow nanorods with NiCoMn-layered double hydroxides(LDH)ternary metal nanosheets,were prepared on carbon cloth by reasonably controlled vulcanization and electrodeposition.By optimizing electrodeposition conditions,the material's structure and properties can be fine-tuned.The enhanced capacitance of the optimized carbon cloth(CC)@CoS/NiCoMn-LDH-300 electrode(4256.0 F g^(-1))lies in the open space provided by CoS and the establishment of a new charge transfer channel across the interfaces of CC@CoS/NiCoMn-LDH-300 nanosheets.This is further demonstrated by Density functional theory(DFT)simulations based on OHadsorption energy,which produces faster redox charge kinetics and significantly enhances the electrode's energy storage capacity.The hybrid supercapacitor,integrating the optimized CC@CoS/NiCoMn-LDH-300 electrode with active carbon,demonstrates the highest energy density of 86 Wh kg^(-1)(under the power density of 850 W kg^(-1))and the long cycle stability of 89.7%.This study aims to go beyond simple binary LDH by constructing a ternary LDH with a hierarchical core-shell heterostructure to provide an effective and feasible new concept for high-performance supercapacitor electrode materials via rational structure design.展开更多
In this work,the synthesis of uniform zeolitic imidazolate framework-coated Mo-glycerate spheres and their subsequent conversion into hierarchical architecture containing bimetallic selenides heterostructures and nitr...In this work,the synthesis of uniform zeolitic imidazolate framework-coated Mo-glycerate spheres and their subsequent conversion into hierarchical architecture containing bimetallic selenides heterostructures and nitrogen-doped carbon shell are reported.Selenization temperature plays a significant role in determining the phases,morphology,and lithium-ion storage performance of the composite.Notably,the optimal electrode demonstrates an ultrahigh reversible capacity of 1298.2 mAh/g after 100 cycles at 0.2 A/g and an outstanding rate capability with the capacity still maintained 505.7 mAh/g after 300 cycles at 1.0 A/g,surpassing the calculated theoretical capacity according to individual component and most of the reported MoSe@C-or ZnSe@C-based anodes.Furthermore,ex-situ X-ray diffraction patterns reveal the combined conversion and alloying reaction mechanisms of the composite.展开更多
Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a pro...Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.展开更多
This paper uses an innovative improved artificial bee colony(IABC)algorithm to aid in the fabrication of a highly responsive phasemodulation surface plasmon resonance(SPR)biosensor.In this biosensor’s sensing structu...This paper uses an innovative improved artificial bee colony(IABC)algorithm to aid in the fabrication of a highly responsive phasemodulation surface plasmon resonance(SPR)biosensor.In this biosensor’s sensing structure,a double-layer Ag-Au metal film is combined with a blue phosphorene/transition metal dichalcogenide(BlueP/TMDC)hybrid structure and graphene.In the optimization function of the IABC method,the reflectivity at resonance angle is incorporated as a constraint to achieve high phase sensitivity.The performance of the Ag-Au-BlueP/TMDC-graphene heterostructure as optimized by the IABC method is compared with that of a similar structure optimized using the traditional ABC algorithm.The results indicate that optimization using the IABC method gives significantly more phase sensitivity,together with lower reflectivity,than can be achieved with the traditional ABC method.The highest phase sensitivity of 3.662×10^(6) °/RIU is achieved with a bilayer of BlueP/WS2 and three layers of graphene.Moreover,analysis of the electric field distribution demonstrates that the optimal arrangement can be utilized for enhanced detection of small biomolecules.Thus,given the exceptional sensitivity achieved,the proposed method based on the IABC algorithm has great promise for use in the design of high-performance SPR biosensors with a variety of multilayer structures.展开更多
The lithium-oxygen battery(LOB)is a promising source of green energy due to its energy density.However,the development of this technology is limited by the insoluble discharge product it produces.In this work,a cathod...The lithium-oxygen battery(LOB)is a promising source of green energy due to its energy density.However,the development of this technology is limited by the insoluble discharge product it produces.In this work,a cathode material with a p-n heterostructure of polyaniline(PANI)/ZnS is prepared to trap visible light,utilizing a ZnS quantum dot(ZnS QD)network to form a large number of photogenerated electron–hole pairs,thus promoting the generation and decomposition of Li_(2)O_(2).The prepared PANI/ZnS has an ultra-low overpotential of 0.06 V under illumination.Furthermore,density functional theory theoretical calculation has demonstrated the ability of the heterostructures to adsorb oxygen-containing intermediates,which not only facilitates the growth of Li_(2)O_(2),but also reduces the reaction energy required to decompose Li_(2)O_(2).The present work provides a solution to the problem of insolubility of discharge products in photo-assisted LOB.展开更多
Surface adsorption plays a crucial role in various natural and industrial processes,particularly in the field of energy storage.The adsorption of sodium atoms on 2D layered materials can significantly impact their per...Surface adsorption plays a crucial role in various natural and industrial processes,particularly in the field of energy storage.The adsorption of sodium atoms on 2D layered materials can significantly impact their performance as carriers and electrodes in ion batteries.While it is commonly acknowledged that pristine graphene is not favorable for sodium ion adsorption,the suitability of other 2D materials with similar honeycomb symmetry remains unclear.In this study,we employ systematic first-principles calculations to explore interlayer interactions and electron transfer effects on sodium adsorption on 2D van der Waals(vdW)heterostructures(HTSs)surfaces.Our results demonstrate that sodium adsorption is energetically favorable on these substrates.Moreover,we find that the adsorption strength can be effectively tuned by manipulation of the electron accumulation or depletion of the layer directly interacting with the sodium atom.By stacking these layered materials with different electron abundancy to form vd W HTSs,the charge density of the substrate becomes tunable through interlayer charge transfer.In these vdW HTSs,the adsorption behavior of sodium is primarily controlled by the absorption layer and exhibits a linear correlation with its pz-band center.Additionally,we identify linear correlations between the sodium adsorption energies,the electron loss of the sodium atom,the interlayer charge transfer,and the heights of the adsorbed sodium atom.These discoveries underscore the impact of interlayer electron transfer and interactions on sodium ion adsorption on 2D vd W HTSs and providing new insights into material design for alkali atom adsorption.展开更多
There exists a severe strength-crack tolerance trade-off in dilute magnesium(Mg)alloys.Herein,a heterogeneous Mg-0.6Al-0.6Mn-0.5Zn-0.2Ce-0.2Nd(A200-10)alloy with a high density of dislocations was obtained through low...There exists a severe strength-crack tolerance trade-off in dilute magnesium(Mg)alloys.Herein,a heterogeneous Mg-0.6Al-0.6Mn-0.5Zn-0.2Ce-0.2Nd(A200-10)alloy with a high density of dislocations was obtained through low-temperature extrusion and short-term annealing.The microstructure consists of recrystallized(RXed)and unrecrystallized(unRXed)regions,with a precisely controlled volume fraction ratio of 3:1.The heterogeneous A200-10 alloy exhibits a high tensile yield strength(TYS)of~306 MPa and a superior tensile elongation(TEL)of~18.4%.Based on quasi-in-situ electron backscattered diffraction(EBSD)and scanning electron microscope(SEM)-digital image correlation(DIC)analysis,we find that plastic deformation occurs preferentially in the RXed regions,mediated by the mobiledislocations.As strain increases,strain gradient gradually accumulates at the interface between RXed and un RXed regions,generating hetero-deformation induced(HDI)strengthening and hardening.Besides,there is significant intergranular slip transfer in RXed regions,which can coordinate partial strain incompatibility.Furthermore,heterogeneous interfaces play a crucial role in enhancing crack tolerance.The heterogeneous interface functions as a bridging ligament to withstand stresses,and activates non-basal slips in the un RXed grains near the crack tip.Such activation of extra dislocations not only alleviates stress concentration but also dissipates the energy essential for microcrack propagation,thus effectively blunting the crack tip.Accordingly,the heterogeneous A200-10 alloy obtains an excellent strength and elongation combination.This work is anticipated to provide a valuable avenue for the development of Mg alloys with outstanding performance by regulating the appropriate heterostructure.展开更多
Step heterostructures are predicted to hold a profound catalytic performance because of the rearranged electronic structure at their interface.However,limitations in the morphology of heterostructures prepared by hydr...Step heterostructures are predicted to hold a profound catalytic performance because of the rearranged electronic structure at their interface.However,limitations in the morphology of heterostructures prepared by hydrothermal reactions or molten salt-assisted strategies make it challenging to directly assess charge distribution and evaluate a single interface's hydrogen evolution reaction(HER)performance.Here,we prepared two-dimensional MoO_(2)/MoS_(2) step heterostructures with a large specific surface area by the chemical vapor deposition method.Surface Kelvin probe force microscopy and electrical transport measurement verified the asymmetric charge distribution at a single interface.By fabricating a series of micro on-chip electrocatalytic devices,we investigate the HER performance for a single interface and confirm that the interface is essential for superior catalytic performance.We experimentally confirmed that the enhancement of the HER performance of step heterostructure is attributed to the asymmetric charge distribution at the interface.This work lays a foundation for designing highly efficient catalytic systems based on step heterostructures.展开更多
Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(elec...Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.展开更多
Rechargeable magnesium batteries(RMBs)have garnered significant attention in energy storage applications due to their high capacity,low cost,and high safety.However,the strong polarization effect and slow kinetic de-i...Rechargeable magnesium batteries(RMBs)have garnered significant attention in energy storage applications due to their high capacity,low cost,and high safety.However,the strong polarization effect and slow kinetic de-intercalation of Mg^(2+)in the cathode limit their commercial application.This study presents a novel interface-coupled V_(2)CT_(x)@VS_(4)heterostructure through a one-step hydrothermal process.In this architecture,V_(2)CT_(x)and VS_(4)can mutually support their structural framework,which effectively prevents the structural collapse of V_(2)CT_(x)MXene and the aggregation of VS_(4).Crucially,interfacial coupling between V_(2)CT_(x)and VS_(4)induces strong V-S bonds,substantially enhancing structural stability.Benefiting from these advantages,the heterostructure exhibits high specific capacity(226 mAh g^(-1)at 100 mA g^(-1))and excellent long-cycle stability(89% capacity retention after 1000 cycles at 500 mA g^(-1)).Furthermore,the Mg^(2+)storage mechanism in the V_(2)CT_(x)@VS_(4)composite was elucidated through a series of ex-situ characterizations.This work provides a feasible strategy for designing V_(2)CT_(x)MXene-based cathodes with high capacity and extended cyclability for RMBs.展开更多
The sandwich heterostructures(SHSs)are novel two-dimensional materials that hold great potential as efficient electro-catalysts.In this work,we computationally designed the BC_(3)/TM/Gr SHSs by intercalating transitio...The sandwich heterostructures(SHSs)are novel two-dimensional materials that hold great potential as efficient electro-catalysts.In this work,we computationally designed the BC_(3)/TM/Gr SHSs by intercalating transition metal atoms into the BC_(3)/graphene heterostructure.After the computational screening,only BC_(3)/Sc/Gr,BC_(3)/Ti/Gr,BC_(3)/Y/Gr and BC_(3)/Zr/Gr are validated as stable SHSs.The electron donation from the intercalated TM atom results in the formation of the negatively charged boron atom(B^(δ)-)and activation of the BC_(3)surface,making the BC_(3)/TM/Gr SHSs highly promising as single-atom catalysts(SACs).The BC_(3)/Sc/Gr and BC_(3)/Y/Gr SHSs exhibit potential in carbon dioxide reduction reaction(CO_(2)RR)and carbon monoxide reduction reaction(CORR)electro-catalysis.Particularly,when BC_(3)/Y/Gr SHS serves as CORR electro-catalyst,the step(∗CHO→∗CHOH)is a potential determining step,with an extremely low limiting potential(UL=-0.10 V).The BC_(3)/Ti/Gr and BC_(3)/Zr/Gr SHSs are suitable as hydrogen evolution reaction(HER)electro-catalysts.Specially,the BC_(3)/Ti/Gr SHS serves as an ideal HER electro-catalyst in acid condition,with close-to-zero adsorption free energy(△GH=0.006 eV)and fairly low overall activation barrier(0.20 eV).By analyzing the electronic properties,the unique adsorption activity of the B^(δ)-on H atom and unsaturated CO_(2)RR intermediates is elucidated as the origin of excellent catalytic activity of BC_(3)/TM/Gr SHSs,which is modulated by the intercalated TM atom.Our work is instructive to rational design of SACs towards energy conversion based on non-metal elements.展开更多
In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit...In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit poor proton conductivity and limited catalytic activity.Herein,a novel Sr_(1.95)Fe_(1.4)Co_(0.1)Mo_(0.4)Zr_(0.1)O_(6-δ)(SFCMZ)anode is prepared as PCECs anode for EENDH.Zr doping increases the oxygen vacancies and enhances the proton conductivity of SFCMZ.Moreover,an alloy-oxide heterostructure(Co Fe@SFCMZ)is formed through in-situ exsolution of Co Fe alloy nanoparticles under reduction conditions,generating abundant oxygen vacancies and improving its catalytic activity.Co Fe@SFCMZ cell achieves an electrolysis current density of 0.87 A/cm^(2) at 700℃ under 1.6 V,with an ethane conversion rate of 34.22%and corresponding ethylene selectivity of 93.4%.These results demonstrate that Co Fe@SFCMZ anode exhibits excellent electrocatalytic activity,suggesting promising applications for EENDH.展开更多
Lithium-sulfur batteries(LSBs)are a promising candidate for next-generation energy storage solutions.However,challenges such as the shuttling effect and sluggish Li-S reaction kinetics of lithium polysulfides hinder t...Lithium-sulfur batteries(LSBs)are a promising candidate for next-generation energy storage solutions.However,challenges such as the shuttling effect and sluggish Li-S reaction kinetics of lithium polysulfides hinder their practical application.In this work,we present a mixed-phase heterostructure comprising Co_(0.85)Se and MoSe_(2),supported on nitrogen-doped carbon polyhedrons(NCP),as an effective sulfur host in the LSB cathode.Through a combination of theoretical calculations and experimental validation,we demonstrate that the Co_(0.85)Se-MoSe_(2)heterointerface significantly enhances electron transfer efficiency,thereby boosting the overall reaction kinetics of the sulfur cathode.As a result,the Co_(0.85)Se-MoSe_(2)/NCP/S electrodes exhibit initial specific capacities exceeding 1500 mAh g^(-1)at 0.1 C and retain 666 m Ah g^(-1)at 3 C,with a capacity fade rate of 0.044%per cycle over 500 cycles at 1.0 C.Notably,even at a high sulfur loading of 3 mg cm^(-2)and a reduced electrolyte volume of 6.7μL mgS^(-1),the Co_(0.85)SeMoSe_(2)/NCP/S electrodes maintain a capacity of 432 mAh g^(-1)after 100 cycles at 0.2 C.展开更多
The efficient limitation of the"shuttle effect"of polysulfide from the rational construction of electrocatalysts to accelerate the redox kinetics of polysulfides is extremely important.In this work,the cobal...The efficient limitation of the"shuttle effect"of polysulfide from the rational construction of electrocatalysts to accelerate the redox kinetics of polysulfides is extremely important.In this work,the cobalt/Nickel bimetallic alloy polyhedrons decorated on layered TiO_(2)heterostructure(Co Ni@TiO_(2)/C)derived from MXene and bimetallic metal-organic framework have been prepared through liquid-phase deposition and high-temperature annealing processes.This heterostructure presents excellent electrical conductivity,which facilitates ion diffusion and electron transfer within the battery.Besides,the heterostructure from anchoring the Co Ni bimetallic alloy on the layered TiO_(2)ensures the full exposure of active sites and accelerates polysulfide redox kinetics through chemisorption and catalytic conversion.Considering these advantages mentioned above,when applied as the lithium-sulfur batteries(LSBs)separator modifier,the cell assembled from the Co Ni@TiO_(2)/C modified separator demonstrates high specific capacity(1481.7 mAh/g at 0.5 C),superior rate capability(855.5 mAh/g at 3 C)and excellent cycling performance,which can maintain the high capacity of 856.09 mAh/g after 300 cycles with low capacity decay rate of 0.09%per cycle.Even under a high sulfur loading of 4.4 mg/cm^(2),the cell can still present excellent cycling stability.This study paves the way for the design of novel material for the construction of an outstanding functional separator layer and shines the light on the effective and feasible way for the inhibition of shuttle effect in lithium-sulfur batteries.展开更多
基金supported by the National Key Research&Development Projects of China(Grant No.2022YFA1204100)National Natural Science Foundation of China(Grant No.62488201)+1 种基金CAS Project for Young Scientists in Basic Research(YSBR-003)the Innovation Program of Quantum Science and Technology(2021ZD0302700)。
文摘As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories(TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However,TCAM cells based on conventional silicon-based devices suffer from structural complexity and large footprintlimitations. Here, we demonstrate an ultrafast nonvolatile TCAM cell based on the MoTe2/hBN/multilayergraphene (MLG) van der Waals heterostructure using a top-gated partial floating-gate field-effect transistor(PFGFET) architecture. Based on its ambipolar transport properties, the carrier type in the source/drain andcentral channel regions of the MoTe2 channel can be efficiently tuned by the control gate and top gate, respectively,enabling the reconfigurable operation of the device in either memory or FET mode. When working inthe memory mode, it achieves an ultrafast 60 ns programming/erase speed with a current on-off ratio of ∼105,excellent retention capability, and robust endurance. When serving as a reconfigurable transistor, unipolar p-typeand n-type FETs are obtained by adopting ultrafast 60 ns control-gate voltage pulses with different polarities.The monolithic integration of memory and logic within a single device enables the content-addressable memory(CAM) functionality. Finally, by integrating two PFGFETs in parallel, a TCAM cell with a high current ratioof ∼10^(5) between the match and mismatch states is achieved without requiring additional peripheral circuitry.These results provide a promising route for the design of high-performance TCAM devices for future in-memorycomputing applications.
基金supported by the National Key R&D Program of China(2021YFB3601000,2021YFB3601004)the National Key R&D Program of China(2022YFB3604702)the Chinese Academy of Sciences.
文摘In recent years,research focusing on synaptic device based on phototransistors has provided a new method for asso-ciative learning and neuromorphic computing.A TiO_(2)/AlGaN/GaN heterostructure-based synaptic phototransistor is fabricated and measured,integrating a TiO_(2)nanolayer gate and a two-dimensional electron gas(2DEG)channel to mimic the synaptic weight and the synaptic cleft,respectively.The maximum drain to source current is 10 nA,while the device is driven at a reverse bias not exceeding-2.5 V.A excitatory postsynaptic current(EPSC)of 200 nA can be triggered by a 365 nm UVA light spike with the duration of 1 s at light intensity of 1.35μW·cm^(-2).Multiple synaptic neuromorphic functions,including EPSC,short-term/long-term plasticity(STP/LTP)and paried-pulse facilitation(PPF),are effectively mimicked by our GaN-based het-erostructure synaptic device.In the typical Pavlov’s dog experiment,we demonstrate that the device can achieve"retraining"process to extend memory time through enhancing the intensity of synaptic weight,which is similar to the working mecha-nism of human brain.
基金support from the China Scholarship Council(No.202107000038)support from the National Natural Science Foundation of China(Nos.52004227,52061040,and 12222209)the China Postdoctoral Science Foundation(No:2021M692512).
文摘This study aims to achieve a synergy of strength and ductility in magnesium-based nanocomposite materials through the design of a dual-heterostructure. Utilizing ball milling and hot extrusion, a nano-TiC/AZ61 composite featuring particle-rare coarse grain (CG) and particle-rich fine grain (FG) zones was successfully fabricated. Experimental results demonstrated that compared with the homogeneous structure, the dual-heterostructure composite achieved a significant increase in elongation by 116 % and a remarkable 165 % improvement in the strength-ductility product (SDP), while maintaining a high ultimate tensile strength (UTS) of 417±4 MPa. This substantial performance enhancement is primarily attributed to the additional strain hardening induced by hetero-deformation-induced (HDI) strain hardening and crack-blunting capabilities, as elucidated by microstructural characterization and crystal plasticity finite element modeling (CPFEM). Notably, the strain hardening contribution from the CG zones at the early stage of deformation (≤ 45 % of total plastic deformation amount) is minimal but increases significantly during the subsequent deformation stages. The dislocation increment rate in CG zones (219 %) is observed to be more than double that in FG zones (95 %), attributed to the large grain size and low dislocation density in CG zones, which provide more space for dislocation storage. In addition, the aggravated deformation inhomogeneity as deformation progresses leads to an increase in geometrically necessary dislocations (GNDs) generation near the heterogeneous interface, thereby enhancing HDI hardening. Fracture mechanism analysis indicated that the cracks mainly initiate in the FG region and are effectively blunted upon their propagation to the CG region, necessitating increased energy consumption and indicating higher fracture toughness for the dual-heterostructure composites. This study validates the effectiveness of the dual-heterostructure design in magnesium-based composites, providing a novel understanding of the deformation mechanism through both experimental analysis and CPFEM, paving the way for the development of high-performance, lightweight structural materials.
基金financially supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(No.2016R1A3B1908249,RS202400407199).
文摘Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.
基金supported by the Russian Science Foundation (Grant No. 22-12-00298)supported by the Center of Excellence "Center of Photonics" funded by the Ministry of Science and Higher Education of the Russian Federation, Contract #075-15-2022-316the Theoretical Physics and Mathematics Advancement Foundation "BASIS" scholarship for the support.
文摘In this work,we studied the persistent photoconductivity(PPC)spectra in single HgTe/CdHgTe quantum wells with different growth parameters and different types of dark conductivity.The studies were performed in a wide radiation quantum energy range of 0.62–3.1 eV both at T=4.2 K and at T=77 K.Common features of the PPC spectra for all structures were revealed,and their relation to the presence of a CdTe cap layer in all structures and the appropriate cadmium fraction in the CdHgTe barrier layers was shown.One of the features was associated with the presence of a deep level in the CdTe layer.In addition,the oscillatory behavior of the PPC spectra in the region from 0.8–1.1 eV to 1.2–1.5 eV was observed.It is associated with the cascade emission of longitudinal optical phonons in CdHgTe barrier.
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supported by the National Natural Science Foundation of China(52203147)the Zhejiang Provincial Natural Science Foundation of China(LQ22B010006)+2 种基金the significant science and technology projects of LongMen Laboratory in Henan Province(231100221100)the significant science and technology projects of LongMen Laboratory in Henan Province(231100220100)the Key research and development program of Henan province(231111222200).
文摘Nanostructure engineering and composition rationalization are crucial for materials to become candidates for high-performance supercapacitor.Herein,a novel core-shell heterostructured electrode,combining CoS hollow nanorods with NiCoMn-layered double hydroxides(LDH)ternary metal nanosheets,were prepared on carbon cloth by reasonably controlled vulcanization and electrodeposition.By optimizing electrodeposition conditions,the material's structure and properties can be fine-tuned.The enhanced capacitance of the optimized carbon cloth(CC)@CoS/NiCoMn-LDH-300 electrode(4256.0 F g^(-1))lies in the open space provided by CoS and the establishment of a new charge transfer channel across the interfaces of CC@CoS/NiCoMn-LDH-300 nanosheets.This is further demonstrated by Density functional theory(DFT)simulations based on OHadsorption energy,which produces faster redox charge kinetics and significantly enhances the electrode's energy storage capacity.The hybrid supercapacitor,integrating the optimized CC@CoS/NiCoMn-LDH-300 electrode with active carbon,demonstrates the highest energy density of 86 Wh kg^(-1)(under the power density of 850 W kg^(-1))and the long cycle stability of 89.7%.This study aims to go beyond simple binary LDH by constructing a ternary LDH with a hierarchical core-shell heterostructure to provide an effective and feasible new concept for high-performance supercapacitor electrode materials via rational structure design.
基金supported by the National Natural Science Foundation of China(No.22265017)the Open Fund of Key Laboratory of Eco-functional Polymer Materials of the Ministry of Education(No.KF-21-04).
文摘In this work,the synthesis of uniform zeolitic imidazolate framework-coated Mo-glycerate spheres and their subsequent conversion into hierarchical architecture containing bimetallic selenides heterostructures and nitrogen-doped carbon shell are reported.Selenization temperature plays a significant role in determining the phases,morphology,and lithium-ion storage performance of the composite.Notably,the optimal electrode demonstrates an ultrahigh reversible capacity of 1298.2 mAh/g after 100 cycles at 0.2 A/g and an outstanding rate capability with the capacity still maintained 505.7 mAh/g after 300 cycles at 1.0 A/g,surpassing the calculated theoretical capacity according to individual component and most of the reported MoSe@C-or ZnSe@C-based anodes.Furthermore,ex-situ X-ray diffraction patterns reveal the combined conversion and alloying reaction mechanisms of the composite.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074213,11574108,and 12104253)the National Key R&D Program of China(Grant No.2022YFA1403103)+2 种基金the Major Basic Program of the Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Provincial(Grant No.ZR2023MA082)the Project of Introduction and Cultivation for Young Innovative Talents in Colleges and Universities of Shandong Province。
文摘Ferromagnetic materials play an important role in memory materials,but conventional control methods are often limited by issues such as high power consumption and volatility.Multiferroic heterostructures provide a promising alternative to achieve low power consumption and nonvolatile electric control of magnetic properties.In this paper,a two-dimensional multiferroic van der Waals heterostructure OsCl_(2)/Sc_(2)CO_(2),which is composed of ferromagnetic monolayer OsCl_(2)and ferroelectric monolayer Sc_(2)CO_(2),is studied by first-principles density functional theory.The results show that by reversing the direction of the electric polarization of Sc_(2)CO_(2),OsCl_(2)can be transformed from a semiconductor to a half-metal,demonstrating a nonvolatile electrical manipulation of the heterostructure through ferroelectric polarization.The underlying physical mechanism is explained by band alignments and charge density differences.Furthermore,based on the heterostructure,we construct a multiferroic tunnel junction with a tunnel electroresistance ratio of 3.38×10^(14)%and a tunnel magnetoresistance ratio of 5.04×10^(6)%,allowing control of conduction states via instantaneous electric or magnetic fields.The findings provide a feasible strategy for designing advanced nanodevices based on the giant tunnel electroresistance and tunnel magnetoresistance effects.
基金funded by the National Natural Science Foundation of China(Grant No.52375547)the Natural Science Foundation of Chongqing,China(Grant Nos.CSTB2022NSCQ-BHX0736 and CSTB2022NSCQ-MSX1523)the Chongqing Scientific Institution Incentive Performance Guiding Special Projects(Grant No.CSTB2024JXJL-YFX0034).
文摘This paper uses an innovative improved artificial bee colony(IABC)algorithm to aid in the fabrication of a highly responsive phasemodulation surface plasmon resonance(SPR)biosensor.In this biosensor’s sensing structure,a double-layer Ag-Au metal film is combined with a blue phosphorene/transition metal dichalcogenide(BlueP/TMDC)hybrid structure and graphene.In the optimization function of the IABC method,the reflectivity at resonance angle is incorporated as a constraint to achieve high phase sensitivity.The performance of the Ag-Au-BlueP/TMDC-graphene heterostructure as optimized by the IABC method is compared with that of a similar structure optimized using the traditional ABC algorithm.The results indicate that optimization using the IABC method gives significantly more phase sensitivity,together with lower reflectivity,than can be achieved with the traditional ABC method.The highest phase sensitivity of 3.662×10^(6) °/RIU is achieved with a bilayer of BlueP/WS2 and three layers of graphene.Moreover,analysis of the electric field distribution demonstrates that the optimal arrangement can be utilized for enhanced detection of small biomolecules.Thus,given the exceptional sensitivity achieved,the proposed method based on the IABC algorithm has great promise for use in the design of high-performance SPR biosensors with a variety of multilayer structures.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.52171206 and52271209)Key Project of Hebei Natural Science Foundation(Nos.F2024201031 and E20202201030)+4 种基金Beijing-Tianjin-Hebei Collaborative Innovation Community Construction Project(No.21344301D)the Second Batch of Young Talent of Hebei Province(Nos.70280016160250 and 70280011808)Key Fund in Hebei Province Department of Education China(No.ZD2021014)the Central Government Guide Local Funding Projects for Scientific and Technological Development(Nos.216Z4404G and 206Z4402G)Interdisciplinary Research Program of Natural Science of Hebei University(No.DXK202107)。
文摘The lithium-oxygen battery(LOB)is a promising source of green energy due to its energy density.However,the development of this technology is limited by the insoluble discharge product it produces.In this work,a cathode material with a p-n heterostructure of polyaniline(PANI)/ZnS is prepared to trap visible light,utilizing a ZnS quantum dot(ZnS QD)network to form a large number of photogenerated electron–hole pairs,thus promoting the generation and decomposition of Li_(2)O_(2).The prepared PANI/ZnS has an ultra-low overpotential of 0.06 V under illumination.Furthermore,density functional theory theoretical calculation has demonstrated the ability of the heterostructures to adsorb oxygen-containing intermediates,which not only facilitates the growth of Li_(2)O_(2),but also reduces the reaction energy required to decompose Li_(2)O_(2).The present work provides a solution to the problem of insolubility of discharge products in photo-assisted LOB.
基金the financial support by the National Key Research and Development Program of China(No.2019YFA0708700)the National Natural Science Foundation of China(Nos.62305196,U23B2087 and 62375158)+4 种基金the China Postdoctoral Science Foundation(No.GZC20231498)the Qingdao Postdoctoral Innovation Project(No.QDBSH20240102078)the Postdoctoral Innovation Program of Shandong Province(No.SDCX-ZG-202400318)Science and Technology Research Project of Hubei Provincial Department of Education(No.D20212603)Hubei University of Arts and Science(No.2020kypytd002)。
文摘Surface adsorption plays a crucial role in various natural and industrial processes,particularly in the field of energy storage.The adsorption of sodium atoms on 2D layered materials can significantly impact their performance as carriers and electrodes in ion batteries.While it is commonly acknowledged that pristine graphene is not favorable for sodium ion adsorption,the suitability of other 2D materials with similar honeycomb symmetry remains unclear.In this study,we employ systematic first-principles calculations to explore interlayer interactions and electron transfer effects on sodium adsorption on 2D van der Waals(vdW)heterostructures(HTSs)surfaces.Our results demonstrate that sodium adsorption is energetically favorable on these substrates.Moreover,we find that the adsorption strength can be effectively tuned by manipulation of the electron accumulation or depletion of the layer directly interacting with the sodium atom.By stacking these layered materials with different electron abundancy to form vd W HTSs,the charge density of the substrate becomes tunable through interlayer charge transfer.In these vdW HTSs,the adsorption behavior of sodium is primarily controlled by the absorption layer and exhibits a linear correlation with its pz-band center.Additionally,we identify linear correlations between the sodium adsorption energies,the electron loss of the sodium atom,the interlayer charge transfer,and the heights of the adsorbed sodium atom.These discoveries underscore the impact of interlayer electron transfer and interactions on sodium ion adsorption on 2D vd W HTSs and providing new insights into material design for alkali atom adsorption.
基金Financial support from The National Natural Science Foundation of China(Nos.52222409,U24A20104,and52401049)The National Key Research and Development Program(No.2024YFB3408900)Partial financial support comes from the Fundamental Research Funds for the Central Universities,JLU。
文摘There exists a severe strength-crack tolerance trade-off in dilute magnesium(Mg)alloys.Herein,a heterogeneous Mg-0.6Al-0.6Mn-0.5Zn-0.2Ce-0.2Nd(A200-10)alloy with a high density of dislocations was obtained through low-temperature extrusion and short-term annealing.The microstructure consists of recrystallized(RXed)and unrecrystallized(unRXed)regions,with a precisely controlled volume fraction ratio of 3:1.The heterogeneous A200-10 alloy exhibits a high tensile yield strength(TYS)of~306 MPa and a superior tensile elongation(TEL)of~18.4%.Based on quasi-in-situ electron backscattered diffraction(EBSD)and scanning electron microscope(SEM)-digital image correlation(DIC)analysis,we find that plastic deformation occurs preferentially in the RXed regions,mediated by the mobiledislocations.As strain increases,strain gradient gradually accumulates at the interface between RXed and un RXed regions,generating hetero-deformation induced(HDI)strengthening and hardening.Besides,there is significant intergranular slip transfer in RXed regions,which can coordinate partial strain incompatibility.Furthermore,heterogeneous interfaces play a crucial role in enhancing crack tolerance.The heterogeneous interface functions as a bridging ligament to withstand stresses,and activates non-basal slips in the un RXed grains near the crack tip.Such activation of extra dislocations not only alleviates stress concentration but also dissipates the energy essential for microcrack propagation,thus effectively blunting the crack tip.Accordingly,the heterogeneous A200-10 alloy obtains an excellent strength and elongation combination.This work is anticipated to provide a valuable avenue for the development of Mg alloys with outstanding performance by regulating the appropriate heterostructure.
基金National Natural Science Foundation of China,Grant/Award Numbers:52288102,52090022,62274087,52472306Science Research Project of Hebei Education Department,Grant/Award Number:BJ2021040Natural Science Foundation of Hebei Province of China,Grant/Award Numbers:E2024203054,E2022203109。
文摘Step heterostructures are predicted to hold a profound catalytic performance because of the rearranged electronic structure at their interface.However,limitations in the morphology of heterostructures prepared by hydrothermal reactions or molten salt-assisted strategies make it challenging to directly assess charge distribution and evaluate a single interface's hydrogen evolution reaction(HER)performance.Here,we prepared two-dimensional MoO_(2)/MoS_(2) step heterostructures with a large specific surface area by the chemical vapor deposition method.Surface Kelvin probe force microscopy and electrical transport measurement verified the asymmetric charge distribution at a single interface.By fabricating a series of micro on-chip electrocatalytic devices,we investigate the HER performance for a single interface and confirm that the interface is essential for superior catalytic performance.We experimentally confirmed that the enhancement of the HER performance of step heterostructure is attributed to the asymmetric charge distribution at the interface.This work lays a foundation for designing highly efficient catalytic systems based on step heterostructures.
基金supported by the National Natural Science Foundation of China(Nos.22175060 and 22376062)JSPS Grant-in-Aid for Scientific Research(Nos.JP21H05235,JP22H05478 and JP22F22358)+1 种基金China Postdoctoral Science Foundation(No.2022M722867)the Key Research Project of Higher Education Institutions in Henan Province(No.23A530001).
文摘Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.
基金Financial support from the National Natural Science Foundation of China(52302317)is gratefully acknowledged。
文摘Rechargeable magnesium batteries(RMBs)have garnered significant attention in energy storage applications due to their high capacity,low cost,and high safety.However,the strong polarization effect and slow kinetic de-intercalation of Mg^(2+)in the cathode limit their commercial application.This study presents a novel interface-coupled V_(2)CT_(x)@VS_(4)heterostructure through a one-step hydrothermal process.In this architecture,V_(2)CT_(x)and VS_(4)can mutually support their structural framework,which effectively prevents the structural collapse of V_(2)CT_(x)MXene and the aggregation of VS_(4).Crucially,interfacial coupling between V_(2)CT_(x)and VS_(4)induces strong V-S bonds,substantially enhancing structural stability.Benefiting from these advantages,the heterostructure exhibits high specific capacity(226 mAh g^(-1)at 100 mA g^(-1))and excellent long-cycle stability(89% capacity retention after 1000 cycles at 500 mA g^(-1)).Furthermore,the Mg^(2+)storage mechanism in the V_(2)CT_(x)@VS_(4)composite was elucidated through a series of ex-situ characterizations.This work provides a feasible strategy for designing V_(2)CT_(x)MXene-based cathodes with high capacity and extended cyclability for RMBs.
基金supported by the National Natural Science Foundation of China(No.51972150)the National Key Research Program of China(No.2022YFA1503101)+1 种基金Science and Technology Development Fund,Macao SAR(FDCT No.0024/2022/ITP)the Project of National Center for International Research on Intelligent Nano-Materials and Detection Technology in Environmental Protection,Soochow University(No.SDGH2303).
文摘The sandwich heterostructures(SHSs)are novel two-dimensional materials that hold great potential as efficient electro-catalysts.In this work,we computationally designed the BC_(3)/TM/Gr SHSs by intercalating transition metal atoms into the BC_(3)/graphene heterostructure.After the computational screening,only BC_(3)/Sc/Gr,BC_(3)/Ti/Gr,BC_(3)/Y/Gr and BC_(3)/Zr/Gr are validated as stable SHSs.The electron donation from the intercalated TM atom results in the formation of the negatively charged boron atom(B^(δ)-)and activation of the BC_(3)surface,making the BC_(3)/TM/Gr SHSs highly promising as single-atom catalysts(SACs).The BC_(3)/Sc/Gr and BC_(3)/Y/Gr SHSs exhibit potential in carbon dioxide reduction reaction(CO_(2)RR)and carbon monoxide reduction reaction(CORR)electro-catalysis.Particularly,when BC_(3)/Y/Gr SHS serves as CORR electro-catalyst,the step(∗CHO→∗CHOH)is a potential determining step,with an extremely low limiting potential(UL=-0.10 V).The BC_(3)/Ti/Gr and BC_(3)/Zr/Gr SHSs are suitable as hydrogen evolution reaction(HER)electro-catalysts.Specially,the BC_(3)/Ti/Gr SHS serves as an ideal HER electro-catalyst in acid condition,with close-to-zero adsorption free energy(△GH=0.006 eV)and fairly low overall activation barrier(0.20 eV).By analyzing the electronic properties,the unique adsorption activity of the B^(δ)-on H atom and unsaturated CO_(2)RR intermediates is elucidated as the origin of excellent catalytic activity of BC_(3)/TM/Gr SHSs,which is modulated by the intercalated TM atom.Our work is instructive to rational design of SACs towards energy conversion based on non-metal elements.
基金financially supported by the National Natural Science Foundation of China(Nos.52272190 and 22178023)the National Key R&D Program of China(No.2021YFB4001401)。
文摘In response to the increasing demand of ethylene,electrochemical ethane nonoxidative dehydrogenation(EENDH)to ethylene by protonic ceramic electrolysis cells(PCECs)is developed.However,existing anode materials exhibit poor proton conductivity and limited catalytic activity.Herein,a novel Sr_(1.95)Fe_(1.4)Co_(0.1)Mo_(0.4)Zr_(0.1)O_(6-δ)(SFCMZ)anode is prepared as PCECs anode for EENDH.Zr doping increases the oxygen vacancies and enhances the proton conductivity of SFCMZ.Moreover,an alloy-oxide heterostructure(Co Fe@SFCMZ)is formed through in-situ exsolution of Co Fe alloy nanoparticles under reduction conditions,generating abundant oxygen vacancies and improving its catalytic activity.Co Fe@SFCMZ cell achieves an electrolysis current density of 0.87 A/cm^(2) at 700℃ under 1.6 V,with an ethane conversion rate of 34.22%and corresponding ethylene selectivity of 93.4%.These results demonstrate that Co Fe@SFCMZ anode exhibits excellent electrocatalytic activity,suggesting promising applications for EENDH.
基金support from the 2BoSS project of the ERA-MIN3 program with the Spanish grant number PCI2022-132985/AEI/10.13039/501100011033funding from the Generalitat de Catalunya 2021SGR01581 and 2021SGR00457+9 种基金the European Union NextGenerationEU/PRTR,the Natural Science Foundation of Chongqing(No.2023NSCQ-MSX1669)the Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJZDK202401110)support of the Supercomputing Center of Lanzhou University,Chinasupported by MCIN with funding from European Union NextGenerationEU(PRTR-C17.I1)by Generalitat de Catalunya(In-CAEM Project)support from the project AMaDE(PID2023-149158OB-C43)funded by MCIN/AEI/10.13039/501100011033/funding from the CSC-UAB PhD scholarship programfunding from Grant IU16-014206(METCAM-FIB)funded by the European Union through the European Regional Development Fund(ERDF)support of the Ministry of Research and Universities,Generalitat de Catalunya。
文摘Lithium-sulfur batteries(LSBs)are a promising candidate for next-generation energy storage solutions.However,challenges such as the shuttling effect and sluggish Li-S reaction kinetics of lithium polysulfides hinder their practical application.In this work,we present a mixed-phase heterostructure comprising Co_(0.85)Se and MoSe_(2),supported on nitrogen-doped carbon polyhedrons(NCP),as an effective sulfur host in the LSB cathode.Through a combination of theoretical calculations and experimental validation,we demonstrate that the Co_(0.85)Se-MoSe_(2)heterointerface significantly enhances electron transfer efficiency,thereby boosting the overall reaction kinetics of the sulfur cathode.As a result,the Co_(0.85)Se-MoSe_(2)/NCP/S electrodes exhibit initial specific capacities exceeding 1500 mAh g^(-1)at 0.1 C and retain 666 m Ah g^(-1)at 3 C,with a capacity fade rate of 0.044%per cycle over 500 cycles at 1.0 C.Notably,even at a high sulfur loading of 3 mg cm^(-2)and a reduced electrolyte volume of 6.7μL mgS^(-1),the Co_(0.85)SeMoSe_(2)/NCP/S electrodes maintain a capacity of 432 mAh g^(-1)after 100 cycles at 0.2 C.
基金supported by National Natural Science Foundation of China(Nos.52472194,52101243)Natural Science Foundation of Guangdong Province,China(No.2023A1515012619)the Science and Technology Planning Project of Guangzhou(No.202201010565)。
文摘The efficient limitation of the"shuttle effect"of polysulfide from the rational construction of electrocatalysts to accelerate the redox kinetics of polysulfides is extremely important.In this work,the cobalt/Nickel bimetallic alloy polyhedrons decorated on layered TiO_(2)heterostructure(Co Ni@TiO_(2)/C)derived from MXene and bimetallic metal-organic framework have been prepared through liquid-phase deposition and high-temperature annealing processes.This heterostructure presents excellent electrical conductivity,which facilitates ion diffusion and electron transfer within the battery.Besides,the heterostructure from anchoring the Co Ni bimetallic alloy on the layered TiO_(2)ensures the full exposure of active sites and accelerates polysulfide redox kinetics through chemisorption and catalytic conversion.Considering these advantages mentioned above,when applied as the lithium-sulfur batteries(LSBs)separator modifier,the cell assembled from the Co Ni@TiO_(2)/C modified separator demonstrates high specific capacity(1481.7 mAh/g at 0.5 C),superior rate capability(855.5 mAh/g at 3 C)and excellent cycling performance,which can maintain the high capacity of 856.09 mAh/g after 300 cycles with low capacity decay rate of 0.09%per cycle.Even under a high sulfur loading of 4.4 mg/cm^(2),the cell can still present excellent cycling stability.This study paves the way for the design of novel material for the construction of an outstanding functional separator layer and shines the light on the effective and feasible way for the inhibition of shuttle effect in lithium-sulfur batteries.
