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Grain-boundary segregation and grain growth in nanocrystalline substitutional solid solution alloys

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Journal of materials Science & Technology 2024年第1期168卷 239-249页

作者： Fawei Tang Chao Hou Hao Lu Zhi Zhao Xiaoyan Song Faculty of materials and Manufacturing Key Laboratory of Advanced Functional MaterialsMinistry of Education of ChinaBeijing University of TechnologyBeijing 100124China

A model for describing solute segregation at grain boundaries has been developed for substitutional solid solution alloys,which integrates multiple factors from atomic to microstructural scales.A concept of mo-lar Gibbs free energy of segregation was introduced to evaluate the segregating capability of the solute elements in a closed system,through which the influences of grain boundary structure,grain size,ma-terial composition,and external conditions were described.Based on the evaluation of various energy forms related to solute segregation and grain growth processes,the nature of the thermal stabilization of nanograin structures by solute segregation was disclosed.A criterion for the destabilization of nanostruc-tures,which is determined by the competition of the change rates between the molar Gibbs free energy of segregation and the total energy of grain boundaries with grain size,has been proposed.This study provided guideline to achieve high-temperature stability of nanograin structures of solid solution alloys even for the weakly segregating nanocrystalline systems.

关键词： Substitutional solid solution Grain boundary segregation Thermal stabilization Solute concentration Grain size

Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 747-762页

作者： Hanxiao GUO Peifeng GAO Xingzhe WANG key laboratory of Mechanics on Western Disaster and Environment of ministry of education Key Laboratory of Special Function Materials and Structure Design of Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting applications.With respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic fields.Traditional numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally demanding.Herein,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake coils.This approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic scale.We then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic scale.The results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and efficient.The proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets.

关键词： epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis

Multiscale confinement nitridation in molybdenum carbide for efficient hydrogen production

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Journal of Energy Chemistry 2024年第7期94卷 61-69页

作者： Liming Dai Chenchen Fang Xiaoyuan Zhang Xuefeng Xu Xuanxuan Chen Xinyue Zong Xueming Hu Wenyao Zhang Liang Xue Pan Xiong Yongsheng Fu Jingwen Sun Junwu Zhu key laboratory for Soft Chemistry and functional materials Ministry of EducationNanjing University of Science and TechnologyNanjing 210094JiangsuChina

The molybdenum carbide(Mo_(2)C)has been regarded as one of the most cost-efficient and stable electrocatalyst for the hydrogen evolution reaction(HER)by the virtue of its Pt-like electronic structures.However,the inherent limitation of high density of empty valence band significantly reduces its catalytic reactivity by reason of strong hydrogen desorption resistance.Herein,we propose a multiscale confinement synthesis method to design the nitrogen-rich Mo_(2)C for modulating the band structure via decomposing the pre-coordination bonded polymer in a pressure-tight tube sealing system.Pre-bonded c/N-Mo in the coordination precursor constructs a micro-confinement space,enabling the homogeneous nitrogenization in-situ happened during the formation of Mo_(2)C.Simultaneously,the evolved gases from the precursor decomposition in tube sealing system establish a macro-confinement environment,preventing the lattice N escape and further endowing a continuous nitridation.Combining the multiscale confinement effects,the nitrogen-rich Mo2C displays as high as 25%N-Mo concentration in carbide lattice,leading to a satisfactory band structure.Accordingly,the constructed nitrogen-rich Mo_(2)C reveals an adorable catalytic activity for HER in both alkaline and acid solution.It is anticipated that the multiscale confinement synthesis strategy presents guideline for the rational design of electrocatalysts and beyond.

关键词： Molybdenum carbide Hydrogen evolution reaction Multiscale confinement synthesis Valence band modulation Nitrogen doping

Complementary multicolor electrochromic devices with excellent stability based on porous tin oxide nanosheet scaffold

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Nano Research 2024年第4期17卷 3035-3042页

作者： Chenchen Bian Jinhui Wang Huanhuan Liu Yin Yan Ping Zhang Weilong Yang Sensen Jia Xiaodan Guo Guofa Cai key laboratory for special functional materials of ministry of education National&Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologySchool of Materials and Engineeringand Collaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004China

Electrochromic devices(ECDs)have been extensively investigated as promising candidates in broad cutting-edge applications,such as smart windows,electronic labels,adaptive camouflage,etc.However,they have suffered from either inadequate color variations or poor cycling stability for a long time.Herein,we developed a general strategy to boost the cyclic stability and enrich the color variations of ECDs by scrupulous design of the composition and nanostructure of electrodes,in which porous tin oxide(SnO_(2))nanosheets serve as the scaffold and typical metal oxides or conducting polymers as the active electrochromic materials.Various electrochromic composite materials,including polyaniline(PANI)@SnO_(2),V2O5@SnO_(2),and WO_(3)@SnO_(2) heterostructured nanoarrays were prepared by the facile wet-chemical method.These composite electrodes exhibit remarkable electrochromic performances,e.g.,superior cycling stability(more than 2000 cycles),rich color variations(more than 5 colors for PANI@SnO_(2)),and enlarged optical modulation.These excellent performances account for the heterogenous porous nanoarrays,which not only facilitate the intercalation/extraction of ions but also relieve the stress generated during the electrochemical process.In addition,diverse prototypes of complementary multicolor ECD with excellent cycling stability(over thousands of cycles)and rich color variations(8 colors)were realized for the first time.We believe that our work put forward a general strategy for developing high-quality multicolor complementary electrochromic devices.

关键词： electrochromism tin oxide metal oxide cycling stability multicolor complementary device

Anti-corrosive and highly reversible zinc metal anode enabled by the phenolic resin coating

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Rare Metals 2024年第5期43卷 2115-2124页

作者： Ya-Ping Wang Ya-Di Yang Shu-Qi Duan Li Wang Jia-Shuo Guo An-Qiang Pan School of materials Science and Engineering Hebei University of Technology key laboratory of special functional materials for Ecological Environment and Information (Hebei University of Technology) Ministry of Education key laboratory for New Type of functional materials in Hebei Province Hebei University of Technology School of materials Science and Engineering Central South University

Aqueous zinc-ion batteries have attracted much attention due to their high theoretical capacity,low cost high safety,and eco-friendly.However,challenges such as dendrite growth and side reactions severely hinder the electrochemical performance of the Zn anode,leading to low Coulombic efficiency （CE） or even short circuits Herein,phenolic resin （PF） is used as a protective coating on the surface of the zinc metal electrode.The PF layer can greatly improve the corrosion resistance of the Zn electrode in the electrolyte.Importantly,this artificial electrode/electrolyte interphase also elevates the nucleation barrier and restrains Zn2+2D diffusion,regulating the zinc deposition/dissolution behavior.As a result,PF@Zn symmetric cells exhibit superior performance than that of bare Zn symmetric cells,achieving a stable and dendrite-free cycle of 1400 h.Furthermore,the carbon nanotube MnO2||PF@Zn （CNT/MnO2||PF@Zn） full cell also delivers a long cycle life with a high-capacity retention of about 180.0 m Ah·g-1after 1400 cycles,far exceeding that of bare Zn anode.This work provides a facile strategy for achieving a dendrite-free and rechargeable zinc anode.

关键词： Rechargeable aqueous batteries Zn metal anode Phenolic resin Anti-corrosion

Phosphine-catalyzed acyl-transfer of heteroaryl ketones for the construction of N-fused heterocycles

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Chinese Chemical Letters 2024年第3期35卷 252-256页

作者： Yu Zhang De-Rui Han Dan Ye Hong Lu Hao Wei key laboratory of Synthetic and Natural functional Molecule of the ministry of education College of Chemistry&Materials ScienceNorthwest UniversityXi'an 710069China

An inexpensive phosphine catalyst was used effectively for a transition-metal-free acyl-transfer of N-containing heteroaryl ketones for the rapid synthesis of N-fused heterocycles.The key pre-aromatic spirocyclic intermediate initialized by the single electron transfer(SET)process of Togni's reagentⅡpromoted by the tertiary phosphine resulted in an intriguing and alternative tactic for the cleavage of C–C bonds.By using inexpensive tertiary phosphine as the catalyst,this skeleton-reorganizing approach of N-containing heteroaryl ketones allows a streamlined assembly of complex N-fused heterocycles with broad functional group tolerance.

关键词： Phosphine catalysis Acyl-transfer N-Fused heterocycles C–C bond activation Aromatization

Theoretical screening of cooperative N-bridged dual-atom sites for efficient electrocatalytic nitrogen reduction with remolding insight

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Nano Research 2024年第4期17卷 3413-3422页

作者： Huimei Chen Yan Yang Chi Jiao Zhiwen Zhuo Junjie Mao Yan Liu key laboratory of functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China

The electrocatalytic nitrogen reduction reaction(e-NRR)is a promising alternative method for the Haber–Bosch process.However,it still faces many challenges in searching for high activity,stability,and selectivity catalysts and ascertaining the catalytic mechanism with complete insight.Here,a series of graphene-based N-bridged dual-atom catalysts(M1-N-M2/NC)are systematically investigated via first-principle calculation and a high-throughput screening strategy.The result unveils that N_(2) adsorption on M1-N-M2/NC in bridge-on adsorption mode can effectively break the scaling relationship on single-atom catalysts(SACs).Moreover,V-N-Ru/NC and V-N-Os/NC are systematically screened out as promising e-NRR catalysts,with extremely low limiting potentials of-0.20 and-0.18 V,respectively.Furthermore,the adsorption site competition between*N_(2) and*H,as well as the competitive twin reactions of hydrogen evolution reaction(HER)on intermediates(N_(n)H_(m))during the e-NRR process,is systematically evaluated to form a remodeling insight for the reactions in mechanism,and the e-NRR of new proposed dual-atom catalysts(DACs)is strategically optimized for its high-efficiency performance potential via our remolding insight in e-NRR mechanism.This work provides new ideas and insights for the design and mechanism of e-NRR catalysts and an effective strategy for rapidly screening highly efficient e-NRR catalysts.

关键词： nitrogen reduction dual-atom catalysts high-throughput screening hydrogen evolution reaction density functional theory calculations

High-frequency magnetic properties of biphase Ce_(2)Fe_(17)N_(3)/α-Fe microflakes with easy-plane anisotropy

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Journal of Rare Earths 2024年第1期42卷 110-115,I0004页

作者： Ke Wang Hang Zhang Yuandong Huang Zhibiao Xu Fashen Li Tao Wang key laboratory for Magnetism and Magnetic materials of MOE Lanzhou UniversityLanzhou730000China key laboratory of special Function materials and Structure Design Ministry of EducationLanzhou UniversityLanzhou730000China

Soft magnetic composites(SMCs)are effective as magnetic powder cores in an inductor.Due to high saturation magnetization,large magnetocrystalline anisotropy and high operating frequency of M(metal)-RE(rear earth)soft magnetic composites,it is possible to miniaturize inductor cores by reducing total loss,especially eddy current loss and excess loss at high frequencies.In this article,the characteristics of Ce_(2)Fe_(17)N_(3)/α-Fe(CFN/F)loss per volume and effective permeability reaching a high frequency of 3 MHz are investigated.The biphase CFN/F composite exhibits a high permeability of 16 at 70 MHz,which is two times greater than that of pure Ce_(2)Fe_(17)N_(3)(CFN)powders.The total loss is as low as 545 mW/cm^(3)at 3 MHz and 6 mT.The direct current(DC)-bias properties have a percent of permeability exceeding 65% at H=7960 A/m.This phenomenon indicates that our material has a higher working frequency and lower core loss than other materials;the biphase CFN/F structure is a promising and efficient approach for developing the miniaturized radio frequency(RF)inductor core.

关键词： High frequency Soft magnetic composites Easy-plane anisotropy Permeability spectra Core loss Rare earths

Supramolecular polymer network constructed by a functionalized polyimidazolium salt derived from metal-carbene template approach

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Science China Chemistry 2024年第4期67卷 1224-1228页

作者： Ming-Ming Gan Zi-En Zhang Yi-Fan Zhang Heng Zhang Li-Ying Sun Ying-Feng Han key laboratory of Synthetic and Natural functional Molecule Chemistry of the ministry of education Xi’an Key Laboratory of Functional Supramolecular Structure and MaterialsCollege of Chemistry and Materials ScienceNorthwest UniversityXi’an 710127China

In this study,we present a supramolecular templating approach for constructing polyimidazolium salt containing crown ether and cyclobutane moieties.This strategy involves the formation of metal-carbene templates,photochemical cycloaddition,and subsequent demetallation of metal ions.Driven by the host-guest chemistry between crown ether units and ammonium salts,we successfully fabricated a supramolecular polymer SPN1,which features imidazolium receptors and cyclobutane units.The obtained SPN1 demonstrates outstanding reversible stimulus-response,antibacterial behavior and conductivity.

关键词： metal-carbene template crown ether polyimidazolium salt host-guest chemistry