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High temperature mechanical retention characteristics and oxidation behaviors of the MoSi2（Cr5Si3）–RSiC composites prepared via a PIP-AAMI combined process

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Journal of Advanced Ceramics 2019年第2期8卷 196-208页

作者： Peng-zhao GAO Lei CHENG Zheng YUAN Xiao-pan LIU Han-ning XIAO College of materials science and Engineering Hunan UniversityChangsha 410082China hunan province key laboratory for Advanced Carbon materials and Applied technology Hunan UniversityChangsha 410082China hunan province key laboratory for Spray Deposition technology and Application Hunan UniversityChangsha 410082China

In the present paper,MoSi2(Cr5Si3)–RSiC composites were prepared via a combination of precursor impregnation pyrolysis(PIP) and MoSi2-Si-Cr alloy active melt infiltration(AAMI) process. Composition, microstructure, mechanical retention characteristics, and oxidation behaviors of the composites at elevated temperature were studied. X-ray diffraction(XRD) pattern confirms that the composites mainly compose of 6 H–SiC, hexagonal MoSi2, and tetragonal Cr5Si3. Scanning electron microscopy(SEM) image reveals that nearly denseMoSi2(Cr5Si3)–RSiC composites exhibiting three-dimensionally(3D) interpenetrated network structure are obtained when infiltrated at 2173 K, and the interface combination of the composites mainly depends on the composition ratio of infiltrated phases. Oxidation weight gain rate of the composites is much lower than that of RSiC matrix, where MoSiCr2 possesses the lowest value of 0.1630 mg×cm-2, about 78% lower than that of RSiC after oxidation at 1773 K for 100 h. Also, it possesses the highest mechanical values of 139.54 MPa(flexural strength σf and RT) and 276.77 GPa(elastic modulus Ef and RT), improvement of 73.73% and 29.77% as compared with that of RSiC, respectively. Mechanical properties of the composites increase first and then decrease with the extension of oxidation time at 1773 K, due to the cooperation effect of surface defect reduction via oxidation reaction and thermal stress relaxation in the composites, crystal growth, and thickness increase of the oxide film. Fracture toughness of MoSiCr2 reaches 2.24 MPa·m1/2(1673 K), showing the highest improvement of 31.70% as compared to the RT value.

关键词： MoSi2(Cr5Si3)–RSiC composites precursor impregnation pyrolysis and MoSi2-Si-Cr alloy active melt infiltration (PIP-AAMI) high temperature mechanical characteristic oxidation behavior

Covalent coupling of DNA bases with graphene nanoribbon electrodes: Negative differential resistance, rectifying, and thermoelectric performance

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Chinese Physics B 2020年第10期29卷 418-427页

作者： Peng-Peng Zhang Shi-Hua Tan Xiao-Fang Peng Meng-Qiu Long hunan Provincial key laboratory of materials surface or interface science and technology Central South University of Forestry and TechnologyChangsha 410004China School of Physics and Electronics Central South UniversityChangsha 410083China

By applying nonequilibrium Green's functions in combination with the density-functional theory, we investigate the electronic, thermal, and thermoelectric properties of four kinds of bases in DNA perpendicularly coupling between two ZGNR electrodes. The results show that the electron transport is highly sensitive to different base-ZGNR coupling geometries, and the system can present large rectifying and negative differential resistance effects. Moreover, the fluctuations of electronic transmission and super-low thermal conductance result in significant enhancement of the thermoelectric figure of merit (ZT): the ZT will be over 1.4 at room temperature, and over 1.6 at 200 K. The results show that the base-ZGNR coupling devices can present large rectifying, negative differential resistance, and enhanced thermoelectric effects.

关键词： DNA bases graphene electron transport phonon transport thermoelectric performance

Enhanced selectivity of catalytic hydrogenation of halogenated nitroaromatics by interfacial effects

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无机化学学报 2025年第1期41卷 201-212页

作者： HUANG Rui LIU Shengjie WU Qingyuan ZHENG Nanfeng New Cornerstone science laboratory State Key Laboratory for Physical Chemistry of Solid SurfacesCollaborative Innovation Center of Chemistry for Energy MaterialsNational&Local Joint Engineering Research Center of Preparation Technology of NanomaterialsCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamenFujian 361005China Innovation laboratory for sciences and Technologies of Energy materials of Fujian province(IKKEM) XiamenFujian 361002China

The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic *** was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal *** the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑*** excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.

关键词： halogenated nitroaromatic heterogeneous catalysis hydrogenation selectivity control interfacial effect

interface engineering strategy via electron-defect trimethyl borate additive toward 4.7 V ultrahigh-nickel LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)battery

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Journal of Energy Chemistry 2024年第5期92卷 639-647页

作者： Yilin Zhang Yuqing Chen Qiu He Jinlong Ke Wei Wang Jian-Fang Wu Peng Gao Yanhua Li Jilei Liu College of materials science and Engineering Hunan Joint International Laboratory of Advanced Materials and Technology for Clean EnergyHunan Province Key Laboratory for Advanced Carbon Materials and Applied TechnologyHunan UniversityChangsha 410082HunanChina College of materials science and Engineering Sichuan UniversityChengdu 610065SichuanChina School of materials science and Engineering Hunan Institute of TechnologyHengyang 421002HunanChina

The Li metal battery with ultrahigh-nickel cathode(LiNi_(x)M_(1-x)O_(2),M=Mn,Co,and x≥0.9)under high-voltage is regarded as one of the most promising approaches to fulfill the ambitious target of 400 Wh/***,the practical application is impeded by the instability of electrode/electrolyte interface and Ni-rich cathode *** we proposed an electron-defect electrolyte additive trimethyl borate(TMB)which is paired with the commercial carbonate electrolyte to construct highly conductive fluorine-and boron-rich cathode electrolyte interface(CEI)on LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90)surface and solid electrolyte interphase(SEI)on lithium metal *** modified CEI effectively mitigates the structural transformation from layered to disordered rock-salt phase,and consequently alleviate the dissolution of transition metal ions(TMs)and its“cross-talk”effect,while the enhanced SEI enables stable lithium plating/striping and thus demonstrated good compatibility between electrolyte and lithium metal *** a result,the common electrolyte with 1 wt%TMB enables 4.7 V NCM90/Li cell cycle stably over 100 cycles with 70%capacity *** work highlights the significance of the electron-defect boron compounds for designing desirable interfacial chemistries to achieve high performance NCM90/Li battery under high voltage operation.

关键词： NCM90 batteries Electrolyte additive Trimethyl borate

Controlled growth of vertically stacked In_(2)Se_(3)/WSe_(2) heterostructures for ultrahigh responsivity photodetector

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Nano Research 2024年第3期17卷 1856-1863页

作者： Cheng Zhang Biyuan Zheng Guangcheng Wu Xueying Liu Jiaxin Wu Chengdong Yao Yizhe Wang Zilan Tang Ying Chen Lizhen Fang Luying Huang Dong Li Shengman Li Anlian Pan key laboratory for Micro-Nano Physics and technology of hunan province State Key Laboratory of Chemo/Biosensing and ChemometricsCollege of Materials Science and EngineeringHunan UniversityChangsha 410082China

Transition metal dichalcogenides(TMDCs)are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum ***,the limited light absorption efficiency in atomically thin layers significantly hinders photocarrier generation,thereby impairing the optoelectronic performance and hindering practical ***,we successfully synthesized In_(2)Se_(3)/WSe_(2) heterostructures through a typical two-step chemical vapor deposition(CVD)*** In_(2)Se_(3) nanosheet with strong light absorption capability,serving as the light absorption layer,was integrated with the monolayer WSe_(2),enhancing the photosensitivity of WSe_(2) *** laser irradiation with a wavelength of 520 nm,the In_(2)Se_(3)/WSe_(2) heterostructure device shows an ultrahigh photoresponsivity with a value as high as 2333.5 A/W and a remarkable detectivity reaching up to 6.7×10^(12) Jones,which is the highest among almost the reported TMDCs-based heterostructures grown via CVD even some fabricated by mechanical exfoliation(ME).Combing the advantages of CVD method such as large scale,high yield,and clean interface,the In_(2)Se_(3)/WSe_(2) heterostructures would provide a novel path for future high-performance optoelectronic device.

关键词： transition metal dichalcogenides(TMDCs) In_(2)Se_(3) heterostructure photodetector ultrahigh responsivity

Controllable Vapor Growth of Large-Area Aligned CdS_xSe_(1-x) Nanowires for Visible Range Integratable Photodetectors

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Nano-Micro Letters 2018年第4期10卷 33-41页

作者： Muhammad Shoaib Xiaoxia Wang Xuehong Zhang Qinglin Zhang Anlian Pan key laboratory for Micro-Nano Physics and technology of hunan province State Key Laboratory of Chemo/Biosensing and Chemometrics College of Materials Science and Engineering Hunan University

The controllable growth of large area band gap engineered-semiconductor nanowires(NWs) with precise orientation and position is of immense significance in the development of integrated optoelectronic devices. In this study, we have achieved large area in-plane-aligned CdS_xSe_(1-x) nanowires via chemical vapor deposition method. The orientation and position of the alloyed CdS_xSe_(1-x)NWs could be controlled well by the graphoepitaxial effect and the patterns of Au catalyst. Microstructure characterizations of these as-grown samples reveal that the aligned CdS_xSe_(1-x)NWs possess smooth surface and uniform diameter. The aligned CdS_xSe_(1-x)NWs have strong photoluminescence and high-quality optical waveguide emission covering almost the entire visible wavelength range. Furthermore, photodetectors were constructed based on individual alloyed CdS_xSe_(1-x)NWs. These devices exhibit high performance and fast response speed with photoresponsivity ～670 A W^(-1) and photoresponse time ～76 ms. Present work provides a straightforward way to realize in-plane aligned bandgap engineering in semiconductor NWs for the development of large area NW arrays,which exhibit promising applications in future optoelectronic integrated circuits.

关键词： Graphoepitaxial effect Bandgap engineering CdSxSe1-x nanowires Optical waveguide Photodetectors

CoS_(2)/N,S co-doped mesoporous carbon with 3D micro-nano crosslinked structure as efficient bifunctional oxygen electrocatalysts for zinc-air batteries

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Chinese Chemical Letters 2023年第5期34卷 604-609页

作者： Wei Wang Liqin Li Jie Ouyang Jialin Gong Jie Tian Liang Chen Junlin Huang Binhong He Zhaohui Hou key laboratory of hunan province for Advanced Carbon-based Functional materials School of Chemistry and Chemical EngineeringHunan Institute of Science and TechnologyYueyang 414006China Guangxi key laboratory of Low Energy Material Guangxi Normal UniversityGuilin 541004China Hubei key laboratory of Pollutant Analysis&Reuse technology Hubei Normal UniversityHuangshi 435002China hunan province key laboratory of materials surface&interface science and technology Material Science and Engineering SchoolCentral South University of Forestry and TechnologyChangsha 410004China

This work describes a bifunctional oxygen catalyst made of cobalt disulfide encapsulated in N,S codoped mesoporous carbon with a novel three-dimensional micro-nano crosslinking *** proposed composite materials exhibit promising oxygen electrocatalytic activity and *** composite assembled rechargeable zinc-air battery can achieve a high power density of 208.9 m W/cm^(2),and can be stably cycled for more than 160 ***,the all-solid zinc-air battery assembled with the electrocatalyst also performs *** micro-nano crosslinking and high porosity structure,as well as the large number of active sites generated by the synergy of N,S doping and the close interface between carbon matrix and CoS_(2),contribute to the composite's exceptional electrochemical *** study's rational strategy lays the path for the development of other high-performance bifunctional electrocatalysts.

关键词： Micro-nano crosslinked CoS_2 ORR OER Zn-air battery

Tailoring interfacial electron redistribution of Ni/Fe_(3)O_(4) electrocatalysts for superior overall water splitting

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Journal of Energy Chemistry 2022年第10期31卷 330-338,I0008页

作者： Wenli Xu Wenda Zhong Chenfan Yang Rong Zhao Jing Wu Xuanke Li Nianjun Yang Hubei province key laboratory of Coal Conversion and New Carbon materials Wuhan University of Science and TechnologyWuhan 430081HubeiChina hunan province key laboratory for Advanced Carbon materials and Applied technology Hunan UniversityChangsha 410082HunanChina Institute of materials Engineering University of SiegenSiegen 57076Germany

Exploring highly active earth-abundant bifu nctional electrocatalysts for water splitting at a high output is essential for the forthcoming hydrogen ***-noble Fe_(3)O_(4) catalyst owns outstanding conductivity and its octahedral Fe sites can markedly promote water ***,it lacks active centers on the surface,resulting in its poor activity when used as a catalyst for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).Herein,an electron redistribution strategy is proposed by introducing Ni sites onto the surface of Fe_(3)O_(4)(Ni/Fe_(3)O_(4)).The abundant delocalized electrons,derived from the electronic interaction of Ni and Fe_(3)O_(4) species,significantly optimize the electronic structure of the Ni/Fe_(3)O_(4) catalyst,leading to its improved adsorption *** Ni/Fe_(3)O_(4) catalyst exhibits remarkable bifunctional activity,steadily outputting 1000 mA cm^(-2)at the low overpotential of 387 mV for HER and 338 mV for OER,*** Ni/Fe_(3)O_(4) as a bifunctional catalyst for overall water splitting reaction exhibits the optimal performance with outstanding stability,obtaining a current density of1000 mA cm^(-2)at 1.98 V,much superior to a Pt/C‖IrO_(2)*** analysis and theoretical calculations collectively corroborate that the electron redistribution of Fe_(3)O_(4) is activated by coupling Ni species,leading to the promoted HER and OER *** electron redistribution strategy provides an effective method to activate transition metal-based catalysts which are promising to be utilized as superior electrocatalysts for the industrial overall water splitting reaction.

关键词： Electron redistribution Ni/Fe_(3)O_(4)heterojunction Overall water splitting

Interlayer engineering in 3D graphene skeleton realizing tunable electronic properties at a highly controllable level for piezoresistive sensors

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Nano Research 2023年第7期16卷 8512-8521页

作者： Xunxiang Hu Lingling Tan Xianzhang Wu Jinqing Wang College of Material science and Engineering Hunan Province Key Laboratory of Materials Surface&Interface Science and TechnologyCentral South University of Forestry and TechnologyChangsha 410004China State key laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of materials science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Three-dimensional(3D)graphene is a promising active component for various engineering fields,but its performance is limited by the hidebound electrical conductivity levels and hindered electrical *** we present a novel approach based on interlayer engineering,in which graphene oxide(GO)nanosheets are covalently functionalized with varied molecular lengths of diamine *** has led to the creation of an unprecedented class of 3D graphene with highly adjustable electronic *** calculations and experimental results demonstrate that ethylenediamine,with its small diameter acting as a molecular bridge for facilitating electron transport,has the potential to significantly improve the electrical conductivity of 3D *** contrast,butylene diamine,with its larger diameter,has a reverse effect due to the enlarged spacing of the graphene interlayers,resulting in conductive *** importantly,the moderate conductive level of 3D graphene can be achieved by combining the interlayer spacing expansion effect and theπ-electronic donor ability of aromatic *** resulting 3D graphene exhibits highly tunable electronic properties,which can be easily adjusted in a wide range of 2.56-6.61 S·cm^(-1)compared to pristine GO foam(4.20 S·cm^(-1)).This opens up new possibilities for its use as an active material in a piezoresistive sensor,as it offers remarkable monitoring abilities.

关键词： graphene tunable electronic properties multifunctional composites piezoresistive sensor