Heat dissipation highly relies on the thermal conductivity(κ)of materials.Materials with large bandgaps and signifcant atomic mass ratios,such as BAs,SiC,andθ-TaN,have attracted considerable attention due to their p...Heat dissipation highly relies on the thermal conductivity(κ)of materials.Materials with large bandgaps and signifcant atomic mass ratios,such as BAs,SiC,andθ-TaN,have attracted considerable attention due to their potential for achieving ultra-highκ,with BAs serving as a particularly representative example due to its unique combination of large bandgap and high thermal conductivity.In this paper,the efects of atomic mass modifcation on phonon bandgap andκare systematically investigated using a BAs model,accounting for both three-and four-phonon scattering processes.A 20%increase inκcan be obtained by substituting B,achieved through widening the phonon bandgap,which suppresses phonon scattering.Notably,the AAOO four-phonon scattering channel is more suppressed than the AAO three-phonon channel,leading to an increased phonon lifetime(τ).For As,κcan also be enhanced by 5%when replaced by lighter atoms,such as^(69)As,primarily due to the increased phonon group velocity(υ).We systematically clarify how atomic-mass-induced bandgap variations afectτ,υ,and thereforeκin wide-bandgap systems.Our work provides a specifc scheme for further improving the ultra-highκof materials with large bandgaps,which possesses great guiding signifcance.展开更多
Aberration-corrected annular dark-field scanning transmission electron microscopy(ADF-STEM)is a powerful tool for structural and chemical analysis of materials.Conventional analyses of ADF-STEM images rely on human la...Aberration-corrected annular dark-field scanning transmission electron microscopy(ADF-STEM)is a powerful tool for structural and chemical analysis of materials.Conventional analyses of ADF-STEM images rely on human labeling,making them labor-intensive and prone to subjective error.Here,we introduce a deep-learning-based workflow combining a pix2pix network for image denoising and either a mathematical algorithm local intensity threshold segmentation(LITS)or another deep learning network UNet for chemical identification.After denoising,the processed images exhibit a five-fold improvement in signal-to-noise ratio and a 20%increase in accuracy of atomic localization.Then,we take atomic-resolution images of Y–Ce dual-atom catalysts(DACs)and Fe-doped ReSe_(2) nanosheets as examples to validate the performance.Pix2pix is applied to identify atomic sites in Y–Ce DACs with a location recall of 0.88 and a location precision of 0.99.LITS is used to further differentiate Y and Ce sites by the intensity of atomic sites.Furthermore,pix2pix and UNet workflow with better automaticity is applied to identification of Fe-doped ReSe_(2) nanosheets.Three types of atomic sites(Re,the substitution of Fe for Re,and the adatom of Fe on Re)are distinguished with the identification recall of more than 0.90 and the precision of higher than 0.93.These results suggest that this strategy facilitates high-quality and automated chemical identification of atomic-resolution images.展开更多
Single-atom Fe catalysts show significant promise in the electrocatalytic reduction of CO_(2)(CO_(2)RR),while their performance remains inferior to that of precious metal catalysts due to the overly strong binding of^...Single-atom Fe catalysts show significant promise in the electrocatalytic reduction of CO_(2)(CO_(2)RR),while their performance remains inferior to that of precious metal catalysts due to the overly strong binding of^(*)CO intermediates.Although the introduction of heteroatoms or transition metal sites can modulate the binding strength of^(*)CO on Fe sites,these regulators often induce competitive hydrogen evolution reaction(HER)with reduced Faraday efficiency(FE).In this work,we employ HER-inert Sn as a regulator to tune the electronic structure of Fe,weakening^(*)CO adsorption and enhancing CO_(2)RR performance.Diatomic Fe-Sn pairs supported on N-doped carbon(Fe-Sn/NC)were synthesized,achieving FE for CO exceeding 90%over a broad potential range from−0.4 to−0.9 V versus the reversible hydrogen electrode.Fe-Sn/NC shows a high turnover frequency of 1.5×10^(4)h^(-1),much higher than that of Fe/NC.Characterization results and theoretical calculations demonstrate that bonding Sn site to Fe generates electron-rich Fe centers,effectively reducing the adsorption strength of^(*)CO without triggering HER.Additionally,Fe-Sn/NC exhibits exceptional activity in hydrazine oxidation performance(HzOR).The HzOR-assisted CO_(2)RR system using Fe-Sn/NC as electrodes reduces energy consumption by 38%compared with the conventional CO_(2)RR coupled oxygen evolution reaction system.展开更多
The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the compl...The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the complex precipitation sequences.Here,a detailed investigation has been carried out on the atomic struc-tural evolution of T_(1) precipitate in an aged Al-Cu-Li-Mg-Ag alloy using state-of-the-art Cs-corrected high-angle annular dark field(HAADF)-coupled with integrated differential phase contrast(iDPC)-scanning transmission electron microscopy(STEM)and energy-dispersive X-ray spectroscopy(EDXS)techniques.An intermediate T_(1)’phase between T_(1p) and T_(1) phase,with a crystal structure and orientation rela-tionship consistent with T_(1),but exhibiting different atomic occupancy and chemical composition was found.We observed the atomic structural transformation from T_(1p) to T_(1)’phase(fcc→hcp),involving only 1/12<112>Al shear component.DFT calculation results validated our proposed structural models and the precipitation sequence.Besides,the distributions of minor solute elements(Ag,Mg,and Zn)in the pre-cipitates exhibited significant differences.These findings may contribute to a further understanding of the nucleation mechanism of T_(1) precipitate.展开更多
Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous Si...Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous SiO_(2) refractive index gradient anti-reflective film prepared by atomic layer deposition(ALD).A porous SiO_(2) film with gradual porosity was obtained by phosphoric acid etching of Al_(2)O_(3)/SiO_(2) multilayers with gradient Al2O3 ratios,achieving a gradual decrease in refractive index from the substrate to the surface.The film exhibited an average transmittance as high as 97.8%within the wavelength range from 320 nm to 1200 nm.The environmental adaptability was further enhanced by surface modification using rare earth oxide(REO)La_(2)O_(3),resulting in formation of a lotus leaf-like structure and achieving a water contact angle of 100.0°.These data proved that the modification significantly improved hydrophobic self-cleaning capability while maintaining exceptional transparency of the film.The surface structure of the modified film remained undamaged even after undergoing wipe testing,demonstrating its excellent surface durability.展开更多
Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Her...Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.展开更多
Single-atom catalysts(SACs),in which isolated metal atoms such as palladium(Pd)are anchored on solid supports,promise breakthroughs in energy conversion and catalysis.However,balancing their activity(reaction speed)an...Single-atom catalysts(SACs),in which isolated metal atoms such as palladium(Pd)are anchored on solid supports,promise breakthroughs in energy conversion and catalysis.However,balancing their activity(reaction speed)and stability(longevity)remains challenging,as the interplay between metal atoms,supports,and reactants is poorly understood.展开更多
The bismuth-telluride-based alloy is the only thermoelectric material commercialized for the applications of refrigeration and energy harvesting,but its low cost-effectiveness severely restricts its large-scale ap-pli...The bismuth-telluride-based alloy is the only thermoelectric material commercialized for the applications of refrigeration and energy harvesting,but its low cost-effectiveness severely restricts its large-scale ap-plication.The introduction of a porous structure in bulk thermoelectric materials has been theoretically proven to effectively reduce thermal conductivity and cost.However,the electrical properties of highly porous materials are considerably suppressed due to the strong carrier scattering at the interface be-tween the matrix and pores,ultimately leading to decreased figure of merit,ZT.Here,we use an atomic layer deposition strategy to introduce some hollow glass bubbles with nano-oxide layers into commercial Bi_(0.5)Sb_(1.5)Te_(3)for preparing high-performance porous thermoelectric materials.Experimental results indi-cate that the nano-oxide layers weaken carrier scattering at the interface between pores and matrix while maintaining high-strength phonon scattering,thereby optimizing carrier/phonon transport behaviors,and effectively increasing the ZT by 23.2%(from 0.99 to 1.22 at 350 K).Besides,our strategy has excellent universality confirmed by its effectiveness in improving the ZT of Bi_(2)Te_(2.7)Se_(0.3),therefore demonstrating great potential for developing low-cost and high-performance thermoelectric materials.展开更多
Carbon electrocatalyst materials based on lignocellulosic biomass with multi-components,various dimensions,high carbon content,and hierarchical morphology structures have gained great popularity in electrocatalytic ap...Carbon electrocatalyst materials based on lignocellulosic biomass with multi-components,various dimensions,high carbon content,and hierarchical morphology structures have gained great popularity in electrocatalytic applications recently.Due to the catalytic deficiency of neutral carbon atoms,the usage of single lignocellulosic-based carbon materials in electrocatalysis involving energy storage and conversion presents unsatisfactory applicability.However,atomic-level modulation of lignocellulose-based carbon materials can optimize the electronic structures,charge separation,transfer processes,and so forth,which results in substantially enhanced electrocatalytic performance of carbon-based catalysts.This paper reviews the recent advances in the rational design of lignocellulosic-based carbon materials as electrocatalysts from an atomic-level perspective,such as self/external heteroatom doping and metal modification.Then,through systematic discussion of the design principles and reaction mechanisms of the catalysts,the applications of the prepared lignocellulosic-based catalysts in rechargeable batteries and electrocatalysis are reviewed.Finally,the challenges in improving the catalytic performance of lignocellulosic-based carbon materials as electrocatalysts and the prospects in diverse applications are reviewed.This review contributes to the synthesis strategy of lignocellulose-based carbon electrocatalysts via atomic-level modulation,which in turn promotes the lignocellulose valorization for energy storage and conversion.展开更多
Atomic-scale strain mapping has become increasingly vital for investigating deformation mechanisms and the governing principles of solid materials.This is due to the significant impact of atomic-scale strain on the ph...Atomic-scale strain mapping has become increasingly vital for investigating deformation mechanisms and the governing principles of solid materials.This is due to the significant impact of atomic-scale strain on the physical,chemical,and mechanical properties of nanomaterials that comprise functional devices such as nanoelectronics,communication devices,electromechanical systems,and sensors.The advent of advanced electron microscopes has enabled the acquisition of high-magnification images with atomic resolution,providing an exceptional platform for measuring the atomic-scale strain of solid materials.However,accurate and unified strain mapping methods and standards for evaluating atomic-scale strain distribution remain scarce.Consequently,a unified strain mapping framework is proposed for atomic-scale strain measurement.Utilizing finite deformation analysis and the least-squares mathematical method,two types of atomic-scale strain field mapping methods have been developed,including the phase analysis-based methods(PAD and PAS)and the peak matching-based strain mapping method(PMS)for high-resolution scanning transmission electron microscope images.The prototypical 2D materials,graphene and molybdenum disulfide,serve as the subjects for the strain field mapping research,conducted through both simulation and experimentation.Upon comparing the theoretical strain mapping results of single-layer graphene and molybdenum disulfide with and without defects,it is demonstrated that the proposed strain mapping methods,particularly the PMS method,can accurately describe the large deformation surrounding a significant strain gradient.展开更多
The infinite-layer nickelates,proposed as analogs to superconducting cuprates,provide a promising platform for exploring the mechanisms of unconventional superconductivity.However,the superconductivity has been exclus...The infinite-layer nickelates,proposed as analogs to superconducting cuprates,provide a promising platform for exploring the mechanisms of unconventional superconductivity.However,the superconductivity has been exclusively observed in thin films under atmospheric pressure,underscoring the critical role of the heterointerface.展开更多
In this paper,hierarchical ultra-thin core/shell Ni_(3)S_(2)@MoS_(2)nano-arrays with Mo atomic site grown on nickel foam(Ni_(3)S_(2)@MoS_(2)-NF)were designed and synthesized through the hydrothermal method.When they a...In this paper,hierarchical ultra-thin core/shell Ni_(3)S_(2)@MoS_(2)nano-arrays with Mo atomic site grown on nickel foam(Ni_(3)S_(2)@MoS_(2)-NF)were designed and synthesized through the hydrothermal method.When they are tested as photoelectric catalysis electrodes to anti-bacteria,the Ni_(3)S_(2)@MoS_(2)within core/shell structure exhibits about several times higher rate capability and outstanding cycling stability than traditional photocatalysts.After reacting with water and oxygen,large numbers of extracellular reactive oxygen species on the surface of Ni_(3)S_(2)@MoS_(2)are observed.These reactive oxygen species can penetrate bacterial cells,resulting in a rapid rise of intracellular reactive oxygen species in a short time.The integrity of the bacterial cell membrane is also destroyed,which can be observed in both scanning and transmission images.The synthetic primer was used to specifically label the gene fragment with antibiotic resistance,which was oxidized and eliminated after the photoelectron catalysis(PEC)reaction,proving that this material for PEC antibacterial can not only kill bacteria.Successful elimination of antibiotic-resistance gene fragments can also be achieved.展开更多
Liquefied natural gas storage and transportation as well as space propulsion systems have sparked inter-est in the martensitic transformation and behaviours of 316 L stainless steels(SS)under ultra-cryogenic deformati...Liquefied natural gas storage and transportation as well as space propulsion systems have sparked inter-est in the martensitic transformation and behaviours of 316 L stainless steels(SS)under ultra-cryogenic deformation.In this study,high-resolution transmission electron microscopy(HRTEM)and molecular dy-namics(MD)simulations were used to investigate the atomic arrangements and crystalline defects of deformation-induced γ-austenite→ε-martensite→α'-martensite and γ→α'martensitic transforma-tions in 316 L SS at 15 and 173 K.Theγ→εtransformation involves the glide of Shockley partial dislocations on(111)γplanes without a change in atomic spacing.The formation of anα'inclusion in a singleε-band is achieved by a continuous lattice distortion,accompanied by the formation of a tran-sition zone ofα'and the expansion of the average atomic spacings due to dislocation shuffling.Asα'grows further intoγ,the orientation relationship(OR)of theα'changes by lattice bending.This pro-cess follows the Bogers-Burgers-Olson-Cohen model despite it not occurring on intersecting shear bands.Stacking faults and twins can also serve as nucleation sites forα'at 173 K.We also found that direct transformation of γ→α'occurs by the glide of √6aγ[11(2)]/12 dislocations on every(111)γplane with misfit dislocations.Overall,this study provides,for the first time,insights into the atomic-scale mech-anisms of various two-step and one-step martensitic transformations induced by cryogenic deformation and corresponding local strain,enhancing our understanding of the role of martensitic transformation under ultra-cryogenic-temperature deformation in controlling the properties.展开更多
Efficient water dissociation catalysts are important for reducing the activation energy barrier of water molecules in the field of energy conversio n.Herein,symmetry-bro ken Rh ensemble induced by mandated charge was ...Efficient water dissociation catalysts are important for reducing the activation energy barrier of water molecules in the field of energy conversio n.Herein,symmetry-bro ken Rh ensemble induced by mandated charge was established to boost the catalytic activity toward water dissociation.As an experimental verification,the turnover frequency of 1.0-RTO_(V4)in hydrogen generation from ammonia borane hydrolysis reaches up to 2838 min-1(24828 min^(-1)depend on Rh dispersion),exceeding the benchmark set up by state-of-the-art catalysts.The transfer of mandated charge from O_(V)to Rh near O_(V)breaks the local symmetry of Rh nanoparticle and forms Rh^(γ-)(electron-aggregation Rh)-Rh interfacial atomic ensemble.This symmetry-broken Rh ensemble is the reason for the high activity of the catalyst.This work provides an effective electronic regulation strategy based on symmetry-broken atomic ensemble induced by mandated charge,designed to stimulate the limiting activity of metal catalyst in the field of next generation energy chemistry.展开更多
In order to better build the neutral beam injector with negative ion source(NNBI),the pre-research on key technologies has been carried out for the comprehensive research facility for fusion technology(CRFFT).Cesium s...In order to better build the neutral beam injector with negative ion source(NNBI),the pre-research on key technologies has been carried out for the comprehensive research facility for fusion technology(CRFFT).Cesium seeding into negative-ion sources is a prerequisite to obtain the required negative hydrogen ion.The performance of ion source largely depends on the cesium conditions in the source.It is very necessary to quantitatively measure the amount of cesium in the source during the plasma on and off periods(vacuum stage).展开更多
The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction(ORR)is essential for the commercialization of proton exchange membrane fuel cells(PEMFCs).Herein,we designed Pt...The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction(ORR)is essential for the commercialization of proton exchange membrane fuel cells(PEMFCs).Herein,we designed Pt@Pt_(3)Ti core-shell nanoparticles with atomic-controllable shells through precise thermal diffusing Ti into Pt nanoparticles for effective and durable ORR.Combining theoretical and experiment analysis,we found that the lattice strain of Pt_(3)Ti shells can be tailored by precisely controlling the thick-ness of Pt_(3)Ti shell in atomic-scale on account of the lattice constant difference between Pt and Pt_(3)Ti to optimize adsorption properties of Pt_(3)Ti for ORR intermediates,thus enhancing its performance.The Pt@Pt_(3)Ti catalyst with one-atomic Pt_(3)Ti shell(Pt@1L-Pt_(3)Ti/TiO_(2)-C)demonstrates excellent performance with mass activity of 592 mA mgpt-1 and durability nearly 19.5-fold that of commercial Pt/C with negligible decay(2%)after 30,000 potential cycles(0.6-1.0 V vs.RHE).Notably,at higher potential cycles(1.0 V-1.5 V vs.RHE),Pt@1L-Pt_(3)Ti/TiO_(2)-C also showed far superior durability than Pt/C(9.6%decayed while 54.8% for commercial Pt/C).This excellent stability is derived from the intrinsic stability of Pt_(3)Ti alloy and the confinement effect of TiO_(2)-C.The catalyst's enhancement was further confirmed in PEMFC configuration.展开更多
Hydrogenation catalysts frequently impose a compromise between activity and selectivity,where maximizing one property inevitably diminishes the other.Researchers from the Dalian Institute of Chemical Physics(DICP)of t...Hydrogenation catalysts frequently impose a compromise between activity and selectivity,where maximizing one property inevitably diminishes the other.Researchers from the Dalian Institute of Chemical Physics(DICP)of the Chinese Academy of Sciences,in collaboration with scholars from University of Science and Technology of China and the Karlsruhe Institute of Technology in Germany,cracked this dilemma by engineering bimetallic catalysts with atomic precision-a breakthrough that boosts hydrogenation efficiency by 35-fold while maintaining pinpoint accuracy,resolving the stubborn activity-selectivity paradox.展开更多
The vortex dynamics after the initial ring dark solitons in two-component ultracold Rydberg atomic systems have been investigated.The two parameters characterizing the Rydberg long-range interaction—namely,the Rydber...The vortex dynamics after the initial ring dark solitons in two-component ultracold Rydberg atomic systems have been investigated.The two parameters characterizing the Rydberg long-range interaction—namely,the Rydberg strength and the blockade radius—along with the initial depth,are identified as the main factors that affect the vortex dynamics.In the absence of Rydberg soft-core potential and spin-orbit coupling,the late vortex dipoles move along x-or y-axis first.However,this work demonstrates that,with certain Rydberg strength and blockade radius,the late vortex dipoles move towards the edge at an oblique angle to the coordinate axes,and it reveals that the Rydberg nonlocal nonlinear interaction shortens the lifetime of late vortices.When the intra-component and inter-component Rydberg strengths are different,the backgrounds of the two components gradually complement each other,and the lifetime of late vortices is significantly shortened.The presented results show that the Rydberg dressing breaks the rule that the initial average depth determines the number and paths of vortices.The motion features of vortex dipoles in the ultracold Rydberg atomic system have been ascertained,and their directions of movement can be predicted to some degree based on the rotation directions and initial positions of the vortices.展开更多
Photocatalytic oxygen reduction for hydrogen peroxide(H_(2)O_(2))synthesis presents a green and costeffective production method.However,achieving highly selective H_(2)O_(2)synthesis remains challenging,necessitating ...Photocatalytic oxygen reduction for hydrogen peroxide(H_(2)O_(2))synthesis presents a green and costeffective production method.However,achieving highly selective H_(2)O_(2)synthesis remains challenging,necessitating precise control over free radical reaction pathways and minimizing undesirable oxidative by-products.Herein,we report for the visible light-driven simultaneous co-photocatalytic reduction of O2to H_(2)O_(2)and oxidation of biomass using the atomic rubidium-nitride modified carbon nitride(CNRb).The optimized CNRb catalyst demonstrates a record photoreduction rate of 8.01 mM h^(-1)for H_(2)O_(2)generation and photooxidation rate of 3.75 mM h^(-1)for furfuryl alcohol to furoic acid,achieving a remarkable solar-to-chemical conversion(SCC)efficiency of up to 2.27%.Experimental characterizations and DFT calculation disclosed that the introducing atomic Rb–N configurations allows for the high-selective generation of superoxide radicals while suppressing hydroxyl free radical formation.This is because the Rb–N serves as the new alternative site to perceive a stronger connection position for O2adsorption and reinforce the capability to extract protons,thereby triggering a high selective redox product formation.This study holds great potential in precisely regulating reactive radical processes at the atomic level,thereby paving the way for efficient synthesis of H_(2)O_(2)coupled with biomass valorization.展开更多
Normally,a transparent inert film is coated on the surface of TiO_(2) particles to enhance the weatherability of the pigment.Liquid-phase coating process is mainly used in industry,which difficult to get really unifor...Normally,a transparent inert film is coated on the surface of TiO_(2) particles to enhance the weatherability of the pigment.Liquid-phase coating process is mainly used in industry,which difficult to get really uniform films.This work combining nanoparticle fluidization technology with atomic layer deposition(ALD) technology to achieve precise surface modification of a large number of micro-nano particles.First,we explored the fluidization characteristics of TiO_(2) nanoparticles in a home-made atmospheric fluidized bed ALD reactor(FB-ALD) to ensure the uniform fluidization of a large number of nanoparticles.Then TiCl_(4) and H_(2)O were used as precursors to deposit amorphous TiO_(2) films on the surface of TiO_(2) nanoparticles at 80℃ under atmospheric pressure,and the growth per cycle was about 0.109 nm per cycle.After 30 ALD cycles,the film thickness was about 3.1 nm,which could almost fully suppress the photocatalytic activity of TiO_(2).Compared with other traditional coating materials,amorphous TiO_(2) has higher light refractive index,and realizes the suppression of the photocatalytic activity of TiO_(2) without introducing other substances,demonstrating greater application potential in TiO_(2) pigment coating field.The process is a gas-phase coating method,which is efficient,no waste water,and easy to scale up.This work shown the excellent property of interface engineering in improving pigment weatherability and can also provide guidance for the nanoparticle surface modification.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2023YFA1407001)the Department of Science and Technology of Jiangsu Province(Grant No.BK20220032)+1 种基金support from the Guang Dong Basic and Applied Basic Research Foundation(Grant No.2023A1515010365)support from the Postgraduate Research and Practice Innovation Program of Jiangsu Province under Grant No.KYCX25_1934。
文摘Heat dissipation highly relies on the thermal conductivity(κ)of materials.Materials with large bandgaps and signifcant atomic mass ratios,such as BAs,SiC,andθ-TaN,have attracted considerable attention due to their potential for achieving ultra-highκ,with BAs serving as a particularly representative example due to its unique combination of large bandgap and high thermal conductivity.In this paper,the efects of atomic mass modifcation on phonon bandgap andκare systematically investigated using a BAs model,accounting for both three-and four-phonon scattering processes.A 20%increase inκcan be obtained by substituting B,achieved through widening the phonon bandgap,which suppresses phonon scattering.Notably,the AAOO four-phonon scattering channel is more suppressed than the AAO three-phonon channel,leading to an increased phonon lifetime(τ).For As,κcan also be enhanced by 5%when replaced by lighter atoms,such as^(69)As,primarily due to the increased phonon group velocity(υ).We systematically clarify how atomic-mass-induced bandgap variations afectτ,υ,and thereforeκin wide-bandgap systems.Our work provides a specifc scheme for further improving the ultra-highκof materials with large bandgaps,which possesses great guiding signifcance.
基金supported by the National Key Research and Development Program of China(2022YFA1505700)National Natural Science Foundation of China(22475214 and 22205232)+2 种基金Talent Plan of Shanghai Branch,Chinese Academy of Sciences(CASSHB-QNPD-2023-020)Natural Science Foundation of Fujian Province(2023J06044)the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences(CXZX-2022-JQ06 and CXZX-2022-GH03)。
文摘Aberration-corrected annular dark-field scanning transmission electron microscopy(ADF-STEM)is a powerful tool for structural and chemical analysis of materials.Conventional analyses of ADF-STEM images rely on human labeling,making them labor-intensive and prone to subjective error.Here,we introduce a deep-learning-based workflow combining a pix2pix network for image denoising and either a mathematical algorithm local intensity threshold segmentation(LITS)or another deep learning network UNet for chemical identification.After denoising,the processed images exhibit a five-fold improvement in signal-to-noise ratio and a 20%increase in accuracy of atomic localization.Then,we take atomic-resolution images of Y–Ce dual-atom catalysts(DACs)and Fe-doped ReSe_(2) nanosheets as examples to validate the performance.Pix2pix is applied to identify atomic sites in Y–Ce DACs with a location recall of 0.88 and a location precision of 0.99.LITS is used to further differentiate Y and Ce sites by the intensity of atomic sites.Furthermore,pix2pix and UNet workflow with better automaticity is applied to identification of Fe-doped ReSe_(2) nanosheets.Three types of atomic sites(Re,the substitution of Fe for Re,and the adatom of Fe on Re)are distinguished with the identification recall of more than 0.90 and the precision of higher than 0.93.These results suggest that this strategy facilitates high-quality and automated chemical identification of atomic-resolution images.
文摘Single-atom Fe catalysts show significant promise in the electrocatalytic reduction of CO_(2)(CO_(2)RR),while their performance remains inferior to that of precious metal catalysts due to the overly strong binding of^(*)CO intermediates.Although the introduction of heteroatoms or transition metal sites can modulate the binding strength of^(*)CO on Fe sites,these regulators often induce competitive hydrogen evolution reaction(HER)with reduced Faraday efficiency(FE).In this work,we employ HER-inert Sn as a regulator to tune the electronic structure of Fe,weakening^(*)CO adsorption and enhancing CO_(2)RR performance.Diatomic Fe-Sn pairs supported on N-doped carbon(Fe-Sn/NC)were synthesized,achieving FE for CO exceeding 90%over a broad potential range from−0.4 to−0.9 V versus the reversible hydrogen electrode.Fe-Sn/NC shows a high turnover frequency of 1.5×10^(4)h^(-1),much higher than that of Fe/NC.Characterization results and theoretical calculations demonstrate that bonding Sn site to Fe generates electron-rich Fe centers,effectively reducing the adsorption strength of^(*)CO without triggering HER.Additionally,Fe-Sn/NC exhibits exceptional activity in hydrazine oxidation performance(HzOR).The HzOR-assisted CO_(2)RR system using Fe-Sn/NC as electrodes reduces energy consumption by 38%compared with the conventional CO_(2)RR coupled oxygen evolution reaction system.
基金supported by the Pre-research fund(No.412130024).
文摘The T_(1)(Al_(2) CuLi)phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li.However,its formation and evolution still need to be further clarified during aging due to the complex precipitation sequences.Here,a detailed investigation has been carried out on the atomic struc-tural evolution of T_(1) precipitate in an aged Al-Cu-Li-Mg-Ag alloy using state-of-the-art Cs-corrected high-angle annular dark field(HAADF)-coupled with integrated differential phase contrast(iDPC)-scanning transmission electron microscopy(STEM)and energy-dispersive X-ray spectroscopy(EDXS)techniques.An intermediate T_(1)’phase between T_(1p) and T_(1) phase,with a crystal structure and orientation rela-tionship consistent with T_(1),but exhibiting different atomic occupancy and chemical composition was found.We observed the atomic structural transformation from T_(1p) to T_(1)’phase(fcc→hcp),involving only 1/12<112>Al shear component.DFT calculation results validated our proposed structural models and the precipitation sequence.Besides,the distributions of minor solute elements(Ag,Mg,and Zn)in the pre-cipitates exhibited significant differences.These findings may contribute to a further understanding of the nucleation mechanism of T_(1) precipitate.
文摘Broadband transparent films play a pivotal role in various applications such as lenses and solar cells,particularly porous structured transparent films exhibit significant potential.This study investigates a porous SiO_(2) refractive index gradient anti-reflective film prepared by atomic layer deposition(ALD).A porous SiO_(2) film with gradual porosity was obtained by phosphoric acid etching of Al_(2)O_(3)/SiO_(2) multilayers with gradient Al2O3 ratios,achieving a gradual decrease in refractive index from the substrate to the surface.The film exhibited an average transmittance as high as 97.8%within the wavelength range from 320 nm to 1200 nm.The environmental adaptability was further enhanced by surface modification using rare earth oxide(REO)La_(2)O_(3),resulting in formation of a lotus leaf-like structure and achieving a water contact angle of 100.0°.These data proved that the modification significantly improved hydrophobic self-cleaning capability while maintaining exceptional transparency of the film.The surface structure of the modified film remained undamaged even after undergoing wipe testing,demonstrating its excellent surface durability.
基金supported by National Natural Science Foundation of China(No.523B2070,No.52225606).
文摘Polymeric perylene diimide(PDI)has been evidenced as a good candidate for photocatalytic water oxidation,yet the origin of the photocatalytic oxygen evolution activity remains unclear and needs further exploration.Herein,with crystal and atomic structures of the self-assembled PDI revealed from the X-ray diffraction pattern,the electronic structure is theoretically illustrated by the first-principles density functional theory calculations,suggesting the suitable band structure and the direct electronic transition for efficient photocatalytic oxygen evolution over PDI.It is confirmed that the carbonyl O atoms on the conjugation structure serve as the active sites for oxygen evolution reaction by the crystal orbital Hamiltonian group analysis.The calculations of reaction free energy changes indicate that the oxygen evolution reaction should follow the reaction pathway of H_(2)O→^(*)OH→^(*)O→^(*)OOH→^(*)O_(2)with an overpotential of 0.81 V.Through an in-depth theoretical computational analysis in the atomic and electronic structures,the origin of photocatalytic oxygen evolution activity for PDI is well illustrated,which would help the rational design and modification of polymeric photocatalysts for efficient oxygen evolution.
文摘Single-atom catalysts(SACs),in which isolated metal atoms such as palladium(Pd)are anchored on solid supports,promise breakthroughs in energy conversion and catalysis.However,balancing their activity(reaction speed)and stability(longevity)remains challenging,as the interplay between metal atoms,supports,and reactants is poorly understood.
基金supported by the National Natural Science Foundation of China(Nos.U21A2054,21905007)the Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(Grant No.202255464).
文摘The bismuth-telluride-based alloy is the only thermoelectric material commercialized for the applications of refrigeration and energy harvesting,but its low cost-effectiveness severely restricts its large-scale ap-plication.The introduction of a porous structure in bulk thermoelectric materials has been theoretically proven to effectively reduce thermal conductivity and cost.However,the electrical properties of highly porous materials are considerably suppressed due to the strong carrier scattering at the interface be-tween the matrix and pores,ultimately leading to decreased figure of merit,ZT.Here,we use an atomic layer deposition strategy to introduce some hollow glass bubbles with nano-oxide layers into commercial Bi_(0.5)Sb_(1.5)Te_(3)for preparing high-performance porous thermoelectric materials.Experimental results indi-cate that the nano-oxide layers weaken carrier scattering at the interface between pores and matrix while maintaining high-strength phonon scattering,thereby optimizing carrier/phonon transport behaviors,and effectively increasing the ZT by 23.2%(from 0.99 to 1.22 at 350 K).Besides,our strategy has excellent universality confirmed by its effectiveness in improving the ZT of Bi_(2)Te_(2.7)Se_(0.3),therefore demonstrating great potential for developing low-cost and high-performance thermoelectric materials.
基金supported by the National Natural Science Foundation of China(32071721,32071720,32271814,32301530,32471806)Tianjin Excellent Special Commissioner for Agricultural Science and Technology Project(23ZYCGSN00580)+4 种基金Young Elite Scientist Sponsorship Program by Cast(No.YESS20230242)Natural Science Foundation of Tianjin(23JCZDJC00630)the China Postdoctoral Science Foundation under Grant Number(2023M741363,2023M740563)the Postdoctoral Innovation Project of Shandong Province(SDCX-ZG-202302031)China Scholarship Council(No.202408120091,No.202408120105).
文摘Carbon electrocatalyst materials based on lignocellulosic biomass with multi-components,various dimensions,high carbon content,and hierarchical morphology structures have gained great popularity in electrocatalytic applications recently.Due to the catalytic deficiency of neutral carbon atoms,the usage of single lignocellulosic-based carbon materials in electrocatalysis involving energy storage and conversion presents unsatisfactory applicability.However,atomic-level modulation of lignocellulose-based carbon materials can optimize the electronic structures,charge separation,transfer processes,and so forth,which results in substantially enhanced electrocatalytic performance of carbon-based catalysts.This paper reviews the recent advances in the rational design of lignocellulosic-based carbon materials as electrocatalysts from an atomic-level perspective,such as self/external heteroatom doping and metal modification.Then,through systematic discussion of the design principles and reaction mechanisms of the catalysts,the applications of the prepared lignocellulosic-based catalysts in rechargeable batteries and electrocatalysis are reviewed.Finally,the challenges in improving the catalytic performance of lignocellulosic-based carbon materials as electrocatalysts and the prospects in diverse applications are reviewed.This review contributes to the synthesis strategy of lignocellulose-based carbon electrocatalysts via atomic-level modulation,which in turn promotes the lignocellulose valorization for energy storage and conversion.
基金support from the National Natural Science Foundation of China through Grants 12172190,11872035,11632010,and 12302236。
文摘Atomic-scale strain mapping has become increasingly vital for investigating deformation mechanisms and the governing principles of solid materials.This is due to the significant impact of atomic-scale strain on the physical,chemical,and mechanical properties of nanomaterials that comprise functional devices such as nanoelectronics,communication devices,electromechanical systems,and sensors.The advent of advanced electron microscopes has enabled the acquisition of high-magnification images with atomic resolution,providing an exceptional platform for measuring the atomic-scale strain of solid materials.However,accurate and unified strain mapping methods and standards for evaluating atomic-scale strain distribution remain scarce.Consequently,a unified strain mapping framework is proposed for atomic-scale strain measurement.Utilizing finite deformation analysis and the least-squares mathematical method,two types of atomic-scale strain field mapping methods have been developed,including the phase analysis-based methods(PAD and PAS)and the peak matching-based strain mapping method(PMS)for high-resolution scanning transmission electron microscope images.The prototypical 2D materials,graphene and molybdenum disulfide,serve as the subjects for the strain field mapping research,conducted through both simulation and experimentation.Upon comparing the theoretical strain mapping results of single-layer graphene and molybdenum disulfide with and without defects,it is demonstrated that the proposed strain mapping methods,particularly the PMS method,can accurately describe the large deformation surrounding a significant strain gradient.
基金supported by the National Natural Science Foundation of China[52125307(to P.G.),12404192(to R.C.S),12274061(to L.Q.)]Key Research and Development Program from the Ministry of Science and Technology(2023YFA1406301)the support from the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘The infinite-layer nickelates,proposed as analogs to superconducting cuprates,provide a promising platform for exploring the mechanisms of unconventional superconductivity.However,the superconductivity has been exclusively observed in thin films under atmospheric pressure,underscoring the critical role of the heterointerface.
基金supported by the Fund of AHBMC-AHU Joint Laboratory of Biomedical Material(No.2022340102000659)the 512 Talent Cultivation Plan of Bengbu Medical College(No.51201313)+1 种基金the Young Scientist Fund of Bengbu Medical College(No.2021byyfyyq02)the Scientific Research Fund of Anhui Provincial Education Department(No.2023AH040290).
文摘In this paper,hierarchical ultra-thin core/shell Ni_(3)S_(2)@MoS_(2)nano-arrays with Mo atomic site grown on nickel foam(Ni_(3)S_(2)@MoS_(2)-NF)were designed and synthesized through the hydrothermal method.When they are tested as photoelectric catalysis electrodes to anti-bacteria,the Ni_(3)S_(2)@MoS_(2)within core/shell structure exhibits about several times higher rate capability and outstanding cycling stability than traditional photocatalysts.After reacting with water and oxygen,large numbers of extracellular reactive oxygen species on the surface of Ni_(3)S_(2)@MoS_(2)are observed.These reactive oxygen species can penetrate bacterial cells,resulting in a rapid rise of intracellular reactive oxygen species in a short time.The integrity of the bacterial cell membrane is also destroyed,which can be observed in both scanning and transmission images.The synthetic primer was used to specifically label the gene fragment with antibiotic resistance,which was oxidized and eliminated after the photoelectron catalysis(PEC)reaction,proving that this material for PEC antibacterial can not only kill bacteria.Successful elimination of antibiotic-resistance gene fragments can also be achieved.
基金supported by the Henry Royce Institute for Advanced Materials,funded through Engineering and Physical Sciences Research Council(EPSRC)grants EP/R00661X/1,EP/S019367/1,EP/P025021/1,and EP/P025498/1.
文摘Liquefied natural gas storage and transportation as well as space propulsion systems have sparked inter-est in the martensitic transformation and behaviours of 316 L stainless steels(SS)under ultra-cryogenic deformation.In this study,high-resolution transmission electron microscopy(HRTEM)and molecular dy-namics(MD)simulations were used to investigate the atomic arrangements and crystalline defects of deformation-induced γ-austenite→ε-martensite→α'-martensite and γ→α'martensitic transforma-tions in 316 L SS at 15 and 173 K.Theγ→εtransformation involves the glide of Shockley partial dislocations on(111)γplanes without a change in atomic spacing.The formation of anα'inclusion in a singleε-band is achieved by a continuous lattice distortion,accompanied by the formation of a tran-sition zone ofα'and the expansion of the average atomic spacings due to dislocation shuffling.Asα'grows further intoγ,the orientation relationship(OR)of theα'changes by lattice bending.This pro-cess follows the Bogers-Burgers-Olson-Cohen model despite it not occurring on intersecting shear bands.Stacking faults and twins can also serve as nucleation sites forα'at 173 K.We also found that direct transformation of γ→α'occurs by the glide of √6aγ[11(2)]/12 dislocations on every(111)γplane with misfit dislocations.Overall,this study provides,for the first time,insights into the atomic-scale mech-anisms of various two-step and one-step martensitic transformations induced by cryogenic deformation and corresponding local strain,enhancing our understanding of the role of martensitic transformation under ultra-cryogenic-temperature deformation in controlling the properties.
基金supported by the National Natural Science Foundation of China(No.22279118,No.22309164)the China Postdoctoral Science Foundation(No.2023M733214)+1 种基金the Young Top Talent Program of Zhongyuan-Yingcai-Jihua(No.30602674)the Special Projects of Henan Province Key Research and Development and Promotion(Science and Technology Research)(No.232102241033)。
文摘Efficient water dissociation catalysts are important for reducing the activation energy barrier of water molecules in the field of energy conversio n.Herein,symmetry-bro ken Rh ensemble induced by mandated charge was established to boost the catalytic activity toward water dissociation.As an experimental verification,the turnover frequency of 1.0-RTO_(V4)in hydrogen generation from ammonia borane hydrolysis reaches up to 2838 min-1(24828 min^(-1)depend on Rh dispersion),exceeding the benchmark set up by state-of-the-art catalysts.The transfer of mandated charge from O_(V)to Rh near O_(V)breaks the local symmetry of Rh nanoparticle and forms Rh^(γ-)(electron-aggregation Rh)-Rh interfacial atomic ensemble.This symmetry-broken Rh ensemble is the reason for the high activity of the catalyst.This work provides an effective electronic regulation strategy based on symmetry-broken atomic ensemble induced by mandated charge,designed to stimulate the limiting activity of metal catalyst in the field of next generation energy chemistry.
基金supported by the HFIPS Director’s Fund(Nos.YZJJQY202204 and 2021YZGH02)the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)+1 种基金the Natural Science Foundation of Anhui Province(No.2208085MA19)the National Key R&D Program of China(Nos.2017YFE300103 and 2017YFE300503)。
文摘In order to better build the neutral beam injector with negative ion source(NNBI),the pre-research on key technologies has been carried out for the comprehensive research facility for fusion technology(CRFFT).Cesium seeding into negative-ion sources is a prerequisite to obtain the required negative hydrogen ion.The performance of ion source largely depends on the cesium conditions in the source.It is very necessary to quantitatively measure the amount of cesium in the source during the plasma on and off periods(vacuum stage).
基金supported by the National Natural Science Foundation of China(No.21875039)the Project on the Integration of Industry-Education-Research of Fujian Province(No.2021H6020)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology).
文摘The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction(ORR)is essential for the commercialization of proton exchange membrane fuel cells(PEMFCs).Herein,we designed Pt@Pt_(3)Ti core-shell nanoparticles with atomic-controllable shells through precise thermal diffusing Ti into Pt nanoparticles for effective and durable ORR.Combining theoretical and experiment analysis,we found that the lattice strain of Pt_(3)Ti shells can be tailored by precisely controlling the thick-ness of Pt_(3)Ti shell in atomic-scale on account of the lattice constant difference between Pt and Pt_(3)Ti to optimize adsorption properties of Pt_(3)Ti for ORR intermediates,thus enhancing its performance.The Pt@Pt_(3)Ti catalyst with one-atomic Pt_(3)Ti shell(Pt@1L-Pt_(3)Ti/TiO_(2)-C)demonstrates excellent performance with mass activity of 592 mA mgpt-1 and durability nearly 19.5-fold that of commercial Pt/C with negligible decay(2%)after 30,000 potential cycles(0.6-1.0 V vs.RHE).Notably,at higher potential cycles(1.0 V-1.5 V vs.RHE),Pt@1L-Pt_(3)Ti/TiO_(2)-C also showed far superior durability than Pt/C(9.6%decayed while 54.8% for commercial Pt/C).This excellent stability is derived from the intrinsic stability of Pt_(3)Ti alloy and the confinement effect of TiO_(2)-C.The catalyst's enhancement was further confirmed in PEMFC configuration.
文摘Hydrogenation catalysts frequently impose a compromise between activity and selectivity,where maximizing one property inevitably diminishes the other.Researchers from the Dalian Institute of Chemical Physics(DICP)of the Chinese Academy of Sciences,in collaboration with scholars from University of Science and Technology of China and the Karlsruhe Institute of Technology in Germany,cracked this dilemma by engineering bimetallic catalysts with atomic precision-a breakthrough that boosts hydrogenation efficiency by 35-fold while maintaining pinpoint accuracy,resolving the stubborn activity-selectivity paradox.
基金supported by the Natural Science Foundation of Hubei Province of China(Grant No.2025AFB370)。
文摘The vortex dynamics after the initial ring dark solitons in two-component ultracold Rydberg atomic systems have been investigated.The two parameters characterizing the Rydberg long-range interaction—namely,the Rydberg strength and the blockade radius—along with the initial depth,are identified as the main factors that affect the vortex dynamics.In the absence of Rydberg soft-core potential and spin-orbit coupling,the late vortex dipoles move along x-or y-axis first.However,this work demonstrates that,with certain Rydberg strength and blockade radius,the late vortex dipoles move towards the edge at an oblique angle to the coordinate axes,and it reveals that the Rydberg nonlocal nonlinear interaction shortens the lifetime of late vortices.When the intra-component and inter-component Rydberg strengths are different,the backgrounds of the two components gradually complement each other,and the lifetime of late vortices is significantly shortened.The presented results show that the Rydberg dressing breaks the rule that the initial average depth determines the number and paths of vortices.The motion features of vortex dipoles in the ultracold Rydberg atomic system have been ascertained,and their directions of movement can be predicted to some degree based on the rotation directions and initial positions of the vortices.
基金National Natural Science Foundation of China(22309032,22109120,and 62104170)Guangdong Basic and Applied Basic Research Foundation(2022A1515011737)+2 种基金Science and Technology Program of Guangzhou(2023A04J1395)GDAS’Project of Science and Technology Development(2021GDASYL-20210102010)Zhejiang Provincial Natural Science Foundation of China(LY23F040001)。
文摘Photocatalytic oxygen reduction for hydrogen peroxide(H_(2)O_(2))synthesis presents a green and costeffective production method.However,achieving highly selective H_(2)O_(2)synthesis remains challenging,necessitating precise control over free radical reaction pathways and minimizing undesirable oxidative by-products.Herein,we report for the visible light-driven simultaneous co-photocatalytic reduction of O2to H_(2)O_(2)and oxidation of biomass using the atomic rubidium-nitride modified carbon nitride(CNRb).The optimized CNRb catalyst demonstrates a record photoreduction rate of 8.01 mM h^(-1)for H_(2)O_(2)generation and photooxidation rate of 3.75 mM h^(-1)for furfuryl alcohol to furoic acid,achieving a remarkable solar-to-chemical conversion(SCC)efficiency of up to 2.27%.Experimental characterizations and DFT calculation disclosed that the introducing atomic Rb–N configurations allows for the high-selective generation of superoxide radicals while suppressing hydroxyl free radical formation.This is because the Rb–N serves as the new alternative site to perceive a stronger connection position for O2adsorption and reinforce the capability to extract protons,thereby triggering a high selective redox product formation.This study holds great potential in precisely regulating reactive radical processes at the atomic level,thereby paving the way for efficient synthesis of H_(2)O_(2)coupled with biomass valorization.
基金supported by the National Natural Science Foundation of China(21808214)Research Project Supported by Shanxi Scholarship Council of China(2023-126)Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(20220013)。
文摘Normally,a transparent inert film is coated on the surface of TiO_(2) particles to enhance the weatherability of the pigment.Liquid-phase coating process is mainly used in industry,which difficult to get really uniform films.This work combining nanoparticle fluidization technology with atomic layer deposition(ALD) technology to achieve precise surface modification of a large number of micro-nano particles.First,we explored the fluidization characteristics of TiO_(2) nanoparticles in a home-made atmospheric fluidized bed ALD reactor(FB-ALD) to ensure the uniform fluidization of a large number of nanoparticles.Then TiCl_(4) and H_(2)O were used as precursors to deposit amorphous TiO_(2) films on the surface of TiO_(2) nanoparticles at 80℃ under atmospheric pressure,and the growth per cycle was about 0.109 nm per cycle.After 30 ALD cycles,the film thickness was about 3.1 nm,which could almost fully suppress the photocatalytic activity of TiO_(2).Compared with other traditional coating materials,amorphous TiO_(2) has higher light refractive index,and realizes the suppression of the photocatalytic activity of TiO_(2) without introducing other substances,demonstrating greater application potential in TiO_(2) pigment coating field.The process is a gas-phase coating method,which is efficient,no waste water,and easy to scale up.This work shown the excellent property of interface engineering in improving pigment weatherability and can also provide guidance for the nanoparticle surface modification.
