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Recent Progress in Emerging Two‑Dimensional Transition Metal Carbides 被引量:4
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作者 Tianchen Qin Zegao Wang +3 位作者 Yuqing Wang Flemming Besenbacher Michal Otyepka Mingdong Dong 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第11期375-408,共34页
As a new member in two-dimensional materials family,transition metal carbides(TMCs)have many excellent properties,such as chemical stability,in-plane anisotropy,high conductivity and flexibility,and remarkable energy ... As a new member in two-dimensional materials family,transition metal carbides(TMCs)have many excellent properties,such as chemical stability,in-plane anisotropy,high conductivity and flexibility,and remarkable energy conversation efficiency,which predispose them for promising applications as transparent electrode,flexible electronics,broadband photodetectors and battery electrodes.However,up to now,their device applications are in the early stage,especially because their controllable synthesis is still a great challenge.This review systematically summarized the state-of-the-art research in this rapidly developing field with particular focus on structure,property,synthesis and applicability of TMCs.Finally,the current challenges and future perspectives are outlined for the application of 2D TMCs. 展开更多
关键词 Two-dimensional transition metal carbides Phase diagram SUPERCONDUCTIVITY Energy conversation and storage Largescale synthesis
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Adhesion between Nonreactive Liquid Metals and Transition Metal Carbides
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作者 李建国 《Rare Metals》 SCIE EI CAS CSCD 1992年第3期177-184,共8页
On the basis of the experimental work of adhesion(W)data,the adhesion between transition metal car- bides and pure liquid metals which do not react with carbides is studied.In view of great scattering of the ex- perim... On the basis of the experimental work of adhesion(W)data,the adhesion between transition metal car- bides and pure liquid metals which do not react with carbides is studied.In view of great scattering of the ex- perimental values of W,a critical analysis of these results is performed.The selected W values for 9 copper/carbide systems and 6 metal/TiC systems are used to discuss the various suggestions concerning the mechanism of adhesion and to evidence the role of the valence electrons of the both carbide and metal on the interactions between metals and carbides.The interactions between a metal and a carbide are essentially metal- lic interactions,resulting from the overlapping of the valence electrons at the metal/carbide interface. 展开更多
关键词 ADHESION Transition metal carbides Pure liquid metal
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Two-Dimensional Transition Metal Carbides and Nitrides(MXenes): Synthesis, Properties, and Electrochemical Energy Storage Applications 被引量:29
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作者 Chuanfang (John) Zhang Yonglu Ma +6 位作者 Xuetao Zhang Sina Abdolhosseinzadeh Hongwei Sheng Wei Lan Amir Pakdel Jakob Heier Frank Nüesch 《Energy & Environmental Materials》 2020年第1期29-55,共27页
A family of 2D transition metal carbides and nitrides known as MXenes has received increasing attention since the discovery of Ti3C2 in 2011. To date, about 30 different MXenes with well-defined structures and propert... A family of 2D transition metal carbides and nitrides known as MXenes has received increasing attention since the discovery of Ti3C2 in 2011. To date, about 30 different MXenes with well-defined structures and properties have been synthesized, and many more are theoretically predicted to exist. Due to the numerous assets including excellent mechanical properties, metallic conductivity,unique in-plane anisotropic structure, tunable band gap, and so on, MXenes rapidly positioned themselves at the forefront of the 2D materials world and have found numerous promising applications. Particular interest is devoted to applications in electrochemical energy storage, whereby 2D MXenes work either as electrodes,additives, separators, or hosts. This review summarizes recent advances in the synthesis, fundamental properties and composites of MXene and highlights the state-of-the-art electrochemical performance of MXene-based electrodes/devices.The progresses in the field of supercapacitors and Li-ion batteries, Li-S batteries, Naand other alkali metal ion batteries are reviewed, and current challenges and new opportunities for MXenes in this surging energy storage field are presented. In the focus of interest is the possibility to boost device-level performance, particularly that of rechargeable batteries, which are of utmost importance in future energy technologies. Very recently, the 2019 Nobel Prize in Chemistry was awarded to the inventors of the Li-ion battery. For sure, this will provide an additional stimulation to study fundamental aspects of electrochemical energy storage. 展开更多
关键词 BATTERY energy storage MXene SUPERCAPACITOR transition metal carbide
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Carbon deficiency introduced plasticity of rock-salt-structured transition metal carbides
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作者 Buhao Zhang Youwei Wang +10 位作者 Jie Yin Yichen Wang Hangfeng Zhang Tamás Csanádi Ján Dusza Michael J.Reece Nan Lin Xiao Yang Xuejian Liu Zhengren Huang Dongliang Jiang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第33期205-214,共10页
High-hardness rock-salt structured transitional metal carbides(TMC)are attracting substantial interest as potential next-generation thermal protection materials.However,the intrinsic brittleness of TMC ceramics impede... High-hardness rock-salt structured transitional metal carbides(TMC)are attracting substantial interest as potential next-generation thermal protection materials.However,the intrinsic brittleness of TMC ceramics impedes their performance in aerodynamically harsh environments.In this work,a promising strategy is proposed to introduce plasticity in TaC–HfC solid solutions by manipulating carbon deficiency.The approach combines density-functional theory(DFT)with experiments and takes Pugh's ratio(k)as the criteria.Depletion of carbon atoms in TaC–HfC solid solutions results in the de-localizing of valence electrons,deviation of spatial modulus along different crystal plane directions,and leading to significant elastic anisotropy.The carbon deficient Ta_(0.8)Hf_(0.2)C_(0.8) is predicted to be a‘softer phase’with reduced modulus and Pugh's ratio(k=0.58).A series of Ta1–xHfxCy(x=0.2 and 0.8,y=0.8,0.9,and 1.0)bulk ceramics are experimentally fabricated by an excessive metal alloying method.Trigonal and hexagonal close-packed structured carbides are derived when the carbon deficiency y decreased to 0.7.The indentation modulus drops from 641.8±14.8 GPa for Ta_(0.8)Hf_(0.2)C_(1.0) to 555.8±9.9 GPa for Ta0.8Hf0.2C0.8.The specific stoichiometric composition of Ta_(0.8)Hf_(0.2)C_(0.8) is experimentally verified to possess both plasticity(k=0.41)and ultra-high nanohardness(41.3±1.3 GPa). 展开更多
关键词 BRITTLE PLASTICITY Transitional metal carbides Pugh's ratio Carbon deficiency
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Achieving ultra-broadband electromagnetic wave absorption in high-entropy transition metal carbides (HE TMCs) 被引量:8
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作者 Weiming ZHANG Huimin XIANG +3 位作者 Fu-Zhi DAI Biao ZHAO Shijiang WU Yanchun ZHOU 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2022年第4期545-555,共11页
Electronic devices pervade everyday life,which has triggered severe electromagnetic(EM)wave pollution.To face this challenge,developing EM wave absorbers with ultra-broadband absorption capacity is critically required... Electronic devices pervade everyday life,which has triggered severe electromagnetic(EM)wave pollution.To face this challenge,developing EM wave absorbers with ultra-broadband absorption capacity is critically required.Currently,nano-composite construction has been widely utilized to realize impedance match and broadband absorption.However,complex experimental procedures,limited thermal stability,and interior oxidation resistance are still unneglectable issues.Therefore,it is appealing to realize ultra-broadband EM wave absorption in single-phase materials with good stability.Aiming at this target,two high-entropy transition metal carbides(HE TMCs)including(Zr,Hf,Nb,Ta)C(HE TMC-2)and(Cr,Zr,Hf,Nb,Ta)C(HE TMC-3)are designed and synthesized,of which the microwave absorption performance is investigated in comparison with previously reported(Ti,Zr,Hf,Nb,Ta)C(HE TMC-1).Due to the synergistic effects of dielectric and magnetic losses,HE TMC-2 and HE TMC-3 exhibit better impedance match and wider effective absorption bandwidth(EAB).In specific,the exclusion of Ti element in HE TMC-2 endows it optimal minimum reflection loss(RL_(min))and EAB of−41.7 dB(2.11 mm,10.52 GHz)and 3.5 GHz(at 3.0 mm),respectively.Remarkably,the incorporation of Cr element in HE TMC-3 significantly improves the impedance match,thus realizing EAB of 10.5,9.2,and 13.9 GHz at 2,3,and 4 mm,respectively.The significance of this study lays on realizing ultra-broadband capacity in HE TMC-3(Cr,Zr,Hf,Nb,Ta),demonstrating the effectiveness of high-entropy component design in tailoring the impedance match. 展开更多
关键词 transition metal carbide(TMC) high-entropy ceramics electromagnetic(EM)wave absorption dielectric and magnetic loss coupling ultra-broadband absorption
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Regulating the formation ability and mechanical properties of high-entropy transition metal carbides by carbon stoichiometry 被引量:2
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作者 Juntao Song Guiqing Chen +5 位作者 Huimin Xiang Fuzhi Dai Shun Dong Wenbo Han Xinghong Zhang Yanchun Zhou 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第26期181-189,共9页
Tremendous efforts have been dedicated to promote the formation ability of high-entropy transition metal carbides.However,the majority of methods for the synthesis of high-entropy transition metal carbides still face ... Tremendous efforts have been dedicated to promote the formation ability of high-entropy transition metal carbides.However,the majority of methods for the synthesis of high-entropy transition metal carbides still face the challenges of high temperature,low efficiency,additional longtime post-treatment and uncontrollable properties.To cope with these challenges,high-entropy transition metal carbides with regulatable carbon stoichiometry(HE TMC)were designed and synthesized,achieving improved ability for single phase solid solutions formation,promoting of sintering and controllable mechanical properties.Two typical composition series,i.e.,easily synthesized(ZrHfTaNb)C(ZHTNC)and difficultly synthesized(Zr_(0.25)Hf_(0.25)Ta_(0.25)Ti_(0.25))C(ZHTTC)are selected to demonstrate the promoting formation ability of single phase solid solutions from carbon stoichiometry deviations.Single phase high-entropy ZHTTC,which has been proven difficult in forming a single phase solid solution,can be prepared with the decrease of C/TM ratio under 2000℃;while the high-entropy ZHTNC,which has been proven easy in forming a single phase solid solution,can be synthesized at lower temperatures with the decrease of C/TM ratio.The synergistic effect of entropy stabilization and reduced chemical bond strength gaining from carbon stoichiometry deviations is responsible for the formation of single phase solid solutions and the promoted sintering of HE TMC.For example,the relative density of bulk(ZrHfTaNb)C(SPS-ZHTNC)increases from 90.98%to 94.25%with decreasing the C/TM atomic ratio from 0.9 to 0.74.More importantly,the room temperature flexural strength,fracture toughness and brittleness index of SPS-ZHTNCcan be tuned in the range of 384 MPa–419 MPa,4.41 MPam–4.73 MPamand 3.679μm–4.083μm,respectively.Thus,the HE TMCprepared by adjusting the ratio of carbon to refractory transition metal oxides have great potential for achieving low temperature synthesis,promoted sintering and tunable properties. 展开更多
关键词 Carbon stoichiometry High-entropy ceramics Transition metal carbide Low temperature synthesis Tunable mechanical properties
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Yarlongite:A New Metallic Carbide Mineral 被引量:3
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作者 SHI Nicheng BAI Wenji +5 位作者 LI Guowu XIONG Ming FANG Qingsong YANG Jingsui MA Zhesheng RONG He 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2009年第1期52-56,共5页
Yarlongite occurs in ophiolitic chromitite at the Luobusha mine (29°5′N 92°5′E, about 200 km ESE of Lhasa), Qusum County, Shannan Prefecture, Tibet Autonomous Region, People's Republic of China. Associa... Yarlongite occurs in ophiolitic chromitite at the Luobusha mine (29°5′N 92°5′E, about 200 km ESE of Lhasa), Qusum County, Shannan Prefecture, Tibet Autonomous Region, People's Republic of China. Associated minerals are: diamond, moissanite, wiistite, iridium ("osmiridium"), osmium ("iridosmine"), periclase, chromite, native iron, native nickel, native chromium, forsterite, Cr-rich diopside, intermetallic compounds Ni-Fe-Cr, Ni-Cr, Cr-C, etc. Yarlongite and its associated minerals were handpicked from a large heavy mineral sample of chromitite. The metallic carbides associated with yarlongite are cohenite, tongbaite, khamrabaevite and qusongite (IMA2007-034). Yarlongite occurs as irregular grains, with a size between 0.02 and 0.06 mm, steel-grey colour, H Mohs: 5^1/2-6. Tenacity: brittle. Cleavage: (0 0 1) perfect. Fracture: conchoidal. Chemical formula: (Cr4Fe4Ni)29C4, or (Cr,Fe,Ni)29C4, Crystal system: Hexagonal, Space Group: P63/mc, a = 18.839(2) A, c = 4.4960 (9) A, V = 745.7(2) A^3, Z = 6, Density (calc.) = 7.19 g/cm3 (with simplified formula). Yariongite has been approved as a new mineral by the CNMNC (IMA2007-035). Holotype material is deposited at the Geological Museum of China (No. Ml1650). 展开更多
关键词 yarlongite new mineral metallic carbides OPHIOLITE LUOBUSHA TIBET
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In-situ preparation, modulation and mechanism of refractory metal carbide gradient coating
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作者 Quan-cai ZHANG Hong WAN Jin-yu GONG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第12期4030-4040,共11页
TiC, ZrC and TaC modified layers were in-situ prepared on graphite matrix by chemical vapor infiltration method with metal salts as the activator. Taking the TiC modified layer as an example, through thermodynamic cal... TiC, ZrC and TaC modified layers were in-situ prepared on graphite matrix by chemical vapor infiltration method with metal salts as the activator. Taking the TiC modified layer as an example, through thermodynamic calculation and experiment, the thermal decomposition process of raw materials(Ti/K_(2)TiF_(6)) was analyzed, the formation mechanism of TiC was determined, and the distribution of TiC modified layer was modulated. The results show that activator K_(2)TiF_(6)has higher decomposition temperature than NH4Cl, which is conducive to improving the utilization rate of raw materials in the gas infiltration process. Increasing the content of Ti powder can increase the concentration of reaction gas and contribute to the formation of TiC modified layer. When the molar ratio of Ti to K_(2)TiF_(6)is 3:1, the surface thickness and infiltration depth of Ti C are 5.42 and 136.24 μm, respectively. Increasing the reaction temperature can improve the rate of in-situ reaction and the thickness of TiC surface layer. When the experimental temperature rises to 1600 °C, the TiC surface layer thickness increases to 20.27 μm. 展开更多
关键词 GRAPHITE TIC in-situ reaction gradient coating chemical vapor infiltration refractory metal carbide
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Experiment and simulation on degradation and burnout mechanisms of SiC MOSFET under heavy ion irradiation 被引量:2
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作者 张鸿 郭红霞 +9 位作者 雷志锋 彭超 张战刚 陈资文 孙常皓 何玉娟 张凤祁 潘霄宇 钟向丽 欧阳晓平 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第2期525-534,共10页
Experiments and simulation studies on 283 MeV I ion induced single event effects of silicon carbide(SiC) metal–oxide–semiconductor field-effect transistors(MOSFETs) were carried out. When the cumulative irradiation ... Experiments and simulation studies on 283 MeV I ion induced single event effects of silicon carbide(SiC) metal–oxide–semiconductor field-effect transistors(MOSFETs) were carried out. When the cumulative irradiation fluence of the SiC MOSFET reached 5×10^(6)ion·cm^(-2), the drain–gate channel current increased under 200 V drain voltage, the drain–gate channel current and the drain–source channel current increased under 350 V drain voltage. The device occurred single event burnout under 800 V drain voltage, resulting in a complete loss of breakdown voltage. Combined with emission microscope, scanning electron microscope and focused ion beam analysis, the device with increased drain–gate channel current and drain–source channel current was found to have drain–gate channel current leakage point and local source metal melt, and the device with single event burnout was found to have local melting of its gate, source, epitaxial layer and substrate. Combining with Monte Carlo simulation and TCAD electrothermal simulation, it was found that the initial area of single event burnout might occur at the source–gate corner or the substrate–epitaxial interface, electric field and current density both affected the lattice temperature peak. The excessive lattice temperature during the irradiation process appeared at the local source contact, which led to the drain–source channel damage. And the excessive electric field appeared in the gate oxide layer, resulting in drain–gate channel damage. 展开更多
关键词 heavy ion silicon carbide metal–oxide–semiconductor field-effect transistors(SiC MOSFET) drain–gate channel drain–source channel single event burnout TCAD simulation
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Proton induced radiation effect of SiC MOSFET under different bias 被引量:1
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作者 张鸿 郭红霞 +11 位作者 雷志锋 彭超 马武英 王迪 孙常皓 张凤祁 张战刚 杨业 吕伟 王忠明 钟向丽 欧阳晓平 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期708-715,共8页
Radiation effects of silicon carbide metal–oxide–semiconductor field-effect transistors(SiC MOSFETs)induced by 20 MeV proton under drain bias(V_(D)=800 V,V_(G)=0 V),gate bias(V_(D)=0 V,V_(G)=10 V),turn-on bias(V_(D)... Radiation effects of silicon carbide metal–oxide–semiconductor field-effect transistors(SiC MOSFETs)induced by 20 MeV proton under drain bias(V_(D)=800 V,V_(G)=0 V),gate bias(V_(D)=0 V,V_(G)=10 V),turn-on bias(V_(D)=0.5 V,V_(G)=4 V)and static bias(V_(D)=0 V,V_(G)=0 V)are investigated.The drain current of SiC MOSFET under turn-on bias increases linearly with the increase of proton fluence during the proton irradiation.When the cumulative proton fluence reaches 2×10^(11)p·cm^(-2),the threshold voltage of SiC MOSFETs with four bias conditions shifts to the left,and the degradation of electrical characteristics of SiC MOSFETs with gate bias is the most serious.In the deep level transient spectrum test,it is found that the defect energy level of SiC MOSFET is mainly the ON2(E_(c)-1.1 eV)defect center,and the defect concentration and defect capture cross section of SiC MOSFET with proton radiation under gate bias increase most.By comparing the degradation of SiC MOSFET under proton cumulative irradiation,equivalent 1 MeV neutron irradiation and gamma irradiation,and combining with the defect change of SiC MOSFET under gamma irradiation and the non-ionizing energy loss induced by equivalent 1 MeV neutron in SiC MOSFET,the degradation of SiC MOSFET induced by proton is mainly caused by ionizing radiation damage.The results of TCAD analysis show that the ionizing radiation damage of SiC MOSFET is affected by the intensity and direction of the electric field in the oxide layer and epitaxial layer. 展开更多
关键词 PROTON silicon carbide metal–oxide–semiconductor field-effect transistor(SiC MOSFET) degradation defect ionization radiation damage
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Spectroscopic characterization of chain-to-ring structural evolution in platinum carbide clusters
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作者 Yu Zhang Shihu Du +5 位作者 Zhi Zhao Haiyan Han Gang Li Jinghan Zou Hua Xie Ling Jiang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第2期529-534,I0014,共7页
Metal carbides play an important role in catalysis and functional materials.However,the structural characterization of metal carbide clusters has been proven to be a challenging experimental target due to the difficul... Metal carbides play an important role in catalysis and functional materials.However,the structural characterization of metal carbide clusters has been proven to be a challenging experimental target due to the difficulty in size selection.Here we use the size-specific photoelectron velocity-map imaging spectroscopy to study the structures and properties of platinum carbide clusters.Quantum chemical calculations are carried out to identify the structures and to assign the experimental spectra.The results indicate that the cluster size of the chain-to-ring structural evolution for the PtC_(n)^(-)anions occurs at n=14,whereas that for the PtC_(n) neutrals at n=10,revealing a significant effect of charge on the structures of metal carbides.The greatest importance of these building blocks is the strong preference of the Pt atom to expose in the outer side of the chain or ring,exhibiting the active sites for catalyzing potential reactions.These findings provide unique spectroscopic snapshots for the formation and growth of platinum carbide clusters and have important implications in the development of related single-atom catalysts with isolated metal atoms dispersed on supports. 展开更多
关键词 CATALYSIS Functional material metal carbide Photoelectron velocity-map imaging spectroscopy Quantum chemical calculation
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A first-principles investigation on mechanical and metallic properties of titanium carbides under pressure 被引量:1
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作者 Xiaojing Sha Namin Xiao +1 位作者 Yongjun Guan Xiaosu Yi 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2018年第10期1953-1958,共6页
The titanium carbides are potential candidates to achieve both high hardness and refractory property. We carried out a structural search for titanium carbides at three pressures of 0 GPa, 30 GPa and 50 GPa. A phase di... The titanium carbides are potential candidates to achieve both high hardness and refractory property. We carried out a structural search for titanium carbides at three pressures of 0 GPa, 30 GPa and 50 GPa. A phase diagram of the Ti-C system at 0 K was obtained by elucidating formation enthalpies as a function of compositions, and their mechanical and metallic properties of titanium carbides were investigated sys- tematically. We also discussed the relation of titanium concentration to the both mechanical and metallic properties of titanium carbides. It has been found that the average valence electron density and tractil-ity improved at higher concentrations of titanium, while the degree of covalent bonding directionality decreased. To this effect, the hardness of titanium carbide decreases as the content of titanium increases. Our results indicated that the titanium content significantly affected the metallic properties of the Ti-C system. 展开更多
关键词 First-principles calculation Transition metal carbides Mechanical property and hardness High pressure phase stability
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Single-source precursor derived high-entropy metal–carbide nanowires:Microstructure and growth evolution 被引量:2
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作者 Junhao Zhao Yulei Zhang +4 位作者 Hui Chen Yanqin Fu Qing Miao Jiachen Meng Jiachen Li 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2023年第11期2041-2052,共12页
In recent years,high-entropy metal carbides(HECs)have attracted significant attention due to their exceptional physical and chemical properties.The combination of excellent performance exhibited by bulk HEC ceramics a... In recent years,high-entropy metal carbides(HECs)have attracted significant attention due to their exceptional physical and chemical properties.The combination of excellent performance exhibited by bulk HEC ceramics and distinctive geometric characteristics has paved the way for the emergence of one-dimensional(1D)HECs as novel materials with unique development potential.Herein,we successfully fabricated novel(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires derived via Fe-assisted single-sourced precursor pyrolysis.Prior to the synthesis of the nanowires,the composition and microstructure of(Ti,Zr,Hf,Nb,Ta)-containing precursor(PHECs)were analyzed,and divinylbenzene(DVB)was used to accelerate the conversion process of the precursor and contribute to the formation of HECs,which also provided a partial carbon source for the nanowire growth.Additionally,multi-branched,single-branched,and single-branched bending nanowires were synthesized by adjusting the ratio of PHECs to DVB.The obtained single-branched(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires possessed smooth surfaces with an average diameter of 130–150 nm and a length of several tens of micrometers,which were a single-crystal structure and typically grew along the[11¯1]direction.Also,the growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires was in agreement with top-type vapor–liquid–solid mechanism.This work not only successfully achieved the fabrication of HEC nanowires by a catalyst-assisted polymer pyrolysis,but also provided a comprehensive analysis of the factors affecting their yield and morphology,highlighting the potential application of these attractive nano-materials. 展开更多
关键词 (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))C nanowires high-entropy metal carbides(HECs) (Ti Zr Hf Nb Ta)-containing precursors vapor–liquid–solid(VLS)mechanism
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The ground-state structure and physical properties of RuC: first-principles calculations
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作者 张美光 闫海燕 +1 位作者 张刚台 王晖 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第7期410-415,共6页
We have extensively explored the ground-state structure of RuC using the particle swarm optimization algorithm for crystal structural prediction. A hexagonal I:t-3m structure has been proposed ms the best candidate, ... We have extensively explored the ground-state structure of RuC using the particle swarm optimization algorithm for crystal structural prediction. A hexagonal I:t-3m structure has been proposed ms the best candidate, which is energetically more favorable than the previously proposed zinc blend structure. The R-3m-RuC possesses alternative stacking of double hexagonal close-packed Ru atom layers and C atom layers, and it is dynamically stable evidenced by the calculation of phonon dispersion. The calculated large bulk modulus, shear modulus, and elastic constant C44 reveal that it is an ultra-incompressible and hard material. The evidence of strong covalent bonding of Ru C, which plays an important role to form a hard material, is manifested by the partial densities of states analysis. 展开更多
关键词 transition metal carbides structure prediction ultra-incompressible material
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Structural and Electronic Properties of ConC3-/0 and ConC4-/0 (n=1-4) Clusters: Mass-Selected Anion Photoelectron Spectroscopy and Density Functional Theory Calculations 被引量:1
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作者 徐西玲 袁金云 +2 位作者 杨斌 许洪光 郑卫军 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2017年第6期717-726,I0002,I0003,共12页
We investigated the structural evolution and elecfronic properties of ConC3-/0 and ConC4-/0 (n=1-4) clusters by using mass-selected photoelectron spectroscopy and density functional theory calculations. The adiabati... We investigated the structural evolution and elecfronic properties of ConC3-/0 and ConC4-/0 (n=1-4) clusters by using mass-selected photoelectron spectroscopy and density functional theory calculations. The adiabatic and vertical detachment energies of CO1-4C3- and COl-4C4- were obtained from their photoelectron spectra. By comparing the theoretical results with the experimental data, the global minimum structures were determined. The results indicate that the carbon atoms of ConC3-/0 and ConC4-/0 (n=1-4) are separated from each other gradually with increasing number of cobalt atoms but a C2 unit still remains at n=4. It is interesting that the Co2C3- and Co2C4- anions have planar structures whereas the neutral Co2C3 and Co2C4 have linear structures with the Co atoms at two ends. The Co3C3- anion has a planar structure with a Co2C2 four-membered ring and a Co3C four-membered ring sharing a Co-Co bond, while the neutral Co3C3 is a three-dimensional structure with a C2 unit and a C atom connecting to two faces of the Co3 triangle. 展开更多
关键词 Photoelectron spectroscopy Transition metal carbide Structural evolution Density functional calculations
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Designing of highly selective and high-temperature endurable RWGS heterogeneous catalysts: recent advances and the future directions 被引量:14
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作者 Xiong Su Xiaoli Yang +1 位作者 Bo Zhao Yanqiang Huang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2017年第5期854-867,共14页
Reverse water gas shift(RWGS) reaction can be served as a pivotal stage of transitioning the abundant CO;resource into chemicals or hydrocarbon fuels, which is attractive for the CO;utilization and of eventually sig... Reverse water gas shift(RWGS) reaction can be served as a pivotal stage of transitioning the abundant CO;resource into chemicals or hydrocarbon fuels, which is attractive for the CO;utilization and of eventually significance in enabling a rebuilt ecological system for unconventional fuels. This concept is appealing when the process is considered as a solution for the storage of renewable energy, which may also find a variety of potential end uses for the outer space exploration. However, a big challenge to this issue is the rational design of high temperature endurable RWGS catalysts with desirable CO product selectivity. In this work, we present a comprehensive overview of recent publications on this research topic,mainly focusing on the catalytic performance of RWGS reaction over three major kinds of heterogeneous catalysts, including supported metal catalysts, mixed oxide catalysts and transition metal carbides. The reaction thermodynamic analysis, kinetics and mechanisms are also described in detail. The present review attempts to provide a general guideline about the construction of well-performed heterogeneous catalysts for the RWGS reaction, as well as discussing the challenges and further prospects of this process. 展开更多
关键词 RWGS reaction Carbon dioxide hydrogenation Supported metal catalyst metal oxide Transition metal carbide
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Single-atom Pt promoted Mo_(2)C for electrochemical hydrogen evolution reaction 被引量:2
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作者 Shanshan Niu Ji Yang +5 位作者 Haifeng Qi Yang Su Zhiyu Wang Jieshan Qiu Aiqin Wang Tao Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第6期371-377,I0009,共8页
Hydrogen generation from electrochemical water splitting powered by renewable energy is important to the sustainable society,but the prohibitive cost of current Pt electrocatalyst has impeded the large-scale productio... Hydrogen generation from electrochemical water splitting powered by renewable energy is important to the sustainable society,but the prohibitive cost of current Pt electrocatalyst has impeded the large-scale production of hydrogen by water electrolysis.In this contribution,a new low-Pt electrocatalyst for hydrogen evolution reaction(HER) has been fabricated by a facile one-pot synthesis approach,in which Pt^(2+)cations and phosphomolybdic acid confined in the metal-organic frameworks(MOFs) were submitted to pyrolysis to yield Pt single atoms dispersed into Mo_(2)C nanocrystals in 3 D porous carbon matrix.The as-synthesized Pt_(1)-Mo_(2)C-C catalyst with Pt content of only 0.7 wt% exhibited remarkably enhanced activity for HER in 1 M KOH,with overpotential at 10 mA/cm^(2) lowered from 211 mV to 155 mV and 7-fold higher mass activity(7.14 A/mgpt) than the benchmark 20 wt% Pt/C.The promoted activity can be attributed to the electronic interaction between Pt single atoms and Mo2C surface,which not only improved water activation but also strengthened hydrogen adsorption,as indicated by FTIR and microcalorimetric characterizations. 展开更多
关键词 metal carbide Pt single atom MOF Hydrogen evolution reaction
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Effect of Mg and Si on infiltration behavior of Al alloys pressureless infiltration into porous SiCp preforms 被引量:10
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作者 Shu-bin Ren Xiao-yu Shen Xuan-hui Qu Xin-bo He 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第6期703-708,共6页
The effect of Mg and Si additon to Al matrix on infiltration kinetics and rates of Al alloys pressureless infiltration into porous SiCp preform was investigated by observing the change of infiltration distance with ti... The effect of Mg and Si additon to Al matrix on infiltration kinetics and rates of Al alloys pressureless infiltration into porous SiCp preform was investigated by observing the change of infiltration distance with time as the Al alloys infiltrate into SiCp preforms at different temperatures.The results show that infiltration of SiCp preforms by Al melt is a thermal activation process and there is an incubation period before the infiltration becomes stable.With the increase of Mg content in the Al alloys from 0wt% to 8wt%,the infiltration will become much easier,the incubation period becomes shorter and the infiltration rate is faster,but these effects are not obvious when the Mg content is higher than 8wt%.As for Si addition to the Al alloys,it has no obvious effect on the incubation period,but the infiltration rate increases markedly with the increase of Si content from 0wt% to 12wt% and the rate has no obvious change when the content is bigger than 12wt%.The effect of Mg and Si on the incubation period is related to the infiltration mechanism of Al pressureless infiltration into SiCp preforms and their impact on the infiltration rate is a combined result from viscosity and surface tension of Al melt and SiC-Al wetting ability. 展开更多
关键词 metallic matrix composites infiltration aluminum alloys silicon carbide preforms
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Design of high-performance molybdenum alloys via doping metal oxide and carbide strengthening:A review 被引量:5
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作者 Hairui Xing Ping Hu +7 位作者 Chaojun He Xiangyang Zhang Jiayu Han Fan Yang Run Bai Wen Zhang Kuaishe Wang Alex AVolinsky 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第29期161-180,共20页
Metal oxide and carbide strengthening molybdenum(Mo)alloys have been designed as promising ad-vanced materials in refractory metals to solve some of the core engineering problems in superalloy ap-plications.Hence,ther... Metal oxide and carbide strengthening molybdenum(Mo)alloys have been designed as promising ad-vanced materials in refractory metals to solve some of the core engineering problems in superalloy ap-plications.Hence,there is a need to summarize the results obtained and evaluate the opportunities for preparing high-performance Mo alloys by strengthening metal oxides and carbides to improve the per-formance characteristics of Mo metal materials.This paper reviews the results of the reported work con-cerning the structure and properties of Mo alloys with different metal oxide and carbide strengthening methods added to Mo matrix.The influence of the doping of La 2 O 3 and Y 2 O 3 particles,ceramic Al 2 O 3 and ZrO 2 particles,and refractory TiC and ZrC carbides particles of Mo alloys are discussed.The impacts of particle morphology,size,distribution and volume fractions of oxide and carbide are analyzed,as well as the specific features of different doping techniques for obtaining high-performance Mo alloys mate-rials.This work will guide future research on the design of high-performance refractory Mo alloys by adding oxides and carbide particles,helping to solve the core issues in the field of superalloy application research. 展开更多
关键词 Molybdenum alloy metal oxide and carbide addition Oxide dispersion-strengthened Carbide precipitation-strengthened Microstructure Mechanical properties
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Pseudo-in-situ stir casting: a new method for production of aluminum matrix composites with bimodal-sized B_4C reinforcement 被引量:1
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作者 Mohammad Raei Masoud Panjepour Mahmood Meratian 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第8期981-990,共10页
A new method was applied to produce an Al-0.5wt%Ti-0.3wt%Zr/5vol%B_4C composite via stir casting with the aim of characterizing the microstructure of the resulting composite. For the production of the composite, large... A new method was applied to produce an Al-0.5wt%Ti-0.3wt%Zr/5vol%B_4C composite via stir casting with the aim of characterizing the microstructure of the resulting composite. For the production of the composite, large B4 C particles(larger than 75 μm) with no pre-heating were added to the stirred melt. Reflected-light microscopy, X-ray diffraction, scanning electron microscopy, field-emission scanning electron microscopy, laser particle size analysis, and image analysis using the Clemex software were performed on the cast samples for microstructural analysis and phase detection. The results revealed that as a consequence of thermal shock, B_4 C particle breakage occurred in the melt. The mechanism proposed for this phenomenon is that the exerted thermal shock in combination with the low thermal shock resistance of B_4 C and large size of the added B_4 C particles were the three key parameters responsible for B_4 C particle breakage. This breakage introduced small particles with sizes less than 10 μm and with no contamination on their surfaces into the melt. The mean particle distance measured via image analysis was approximately 60 μm. The coefficient of variation index, which was used as a measure of particle distribution homogeneity, showed some variations, indicating a relatively homogeneous distribution. 展开更多
关键词 metal matrix composites particle-reinforced composites boron carbide casting thermal shock
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