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H_(2)S-assisted growth of 2D MS_(2)(M=Ti,Zr,Nb)

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Chinese Chemical Letters 2022年第3期33卷 1390-1394页

作者： Yiwei Zhang Peng Zhang Tengfei Xu Xingguo Wang huaning jiang Yongji Gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China

2D transition metal dichalcogenides (TMDCs) have drawn an enormous amount of attention due to their fascinating properties and application potential in next-generation information process and storage. However, the lack of proper synthesis approach limits their application. Here, we report a controllable synthesis method to grow ultrathin MS2 (M = Ti, Nb, Zr) nanosheets with H_(2)S-assisted chemical vapor deposition (CVD). We found that the presence of H_(2)S plays an important role to control the morphology of nanosheets including the lateral size and the nucleation density. With the assistance of H_(2)S, the growth of MS2 shows much thinner thickness with largely decreased nucleation density, beneficial for the device application, which can be attributed to the kinetics dominated growth. Our method hence opens a new avenue for the CVD growth of 2D TMDCs and the corresponding heterojunction, and paves the way for exploring their intriguing properties and applications.

关键词： Chemical vapor deposition Growth mechanism 2D transition-metal dichalcogenides Titanium disulfide FET properties

Enhanced mass transfer in three-dimensional single-atom nickel catalyst with open-pore structure for highly efficient CO_(2) electrolysis

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Journal of Energy Chemistry 2021年第11期30卷 43-50,I0002页

作者： Pengbo Zhai Xiaokang Gu Yi Wei Jinghan Zuo Qian Chen Wei Liu huaning jiang Xingguo Wang Yongji Gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Organic-Inorganic Composites Beijing Key Laboratory of Electrochemical Process and Technology for MaterialsBeijing University of Chemical TechnologyBeijing 100029China

Design of efficient catalysts for electrochemical reduction of carbon dioxide (CO_(2)) with high selectivity and activity is of great challenge, but significant for managing the global carbon balance. Herein, a series of three-dimensional (3D) single-atom metals anchored on graphene networks (3D SAM-G) with open-pore structure were successfully mass-produced via a facile in-situ calcination technique assisted by NaCl template. As-obtained 3D SANi-G electrode delivers excellent CO Faradaic efficiency (FE) of >96% in the potential range of −0.6 to −0.9 V versus reversible hydrogen electrode (RHE) and a high current density of 66.27 mA cm^(−2) at −1.0 V versus RHE, outperforming most of the previously reported catalysts tested in H-type cells. Simulations indicate that enhanced mass transport within the 3D open-pore structure effectively increases the catalytically active sites, which in turn leads to simultaneous enhancement on selectivity and activity of 3D SANi-G toward CO_(2) electroreduction. The cost-effective synthesis approach together with the microstructure design concept inspires new insights for the development of efficient electrocatalysts.

关键词： Open-pore structure Catalytic sites Reactant diffusion Single-atom catalysts CO_(2)electrolysis

Sodium titanate nanowires for Na^(+) -based hybrid energy storage with high power density

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SusMat 2022年第6期2卷 720-730页

作者： Zuo Jinghan Liu Zeyu jiang huaning Chen Qian Yang Zhilin Gu Xiaokang Jiao Yuying Gong Yongji School of Materials Science and Engineering Beihang UniversityBeijingChina Shenyuan Honors College Beihang UniversityBeijingChina

It is crucial to enhance the rate capability of the titanium-based materials for fulfilling their promising potential as the anode materials of sodium-ion bat-teries(SIBs).Herein,Mn-doped sodium titanate(Mn-NTO)nanowires with homogeneously distributed ultrathin carbon nanosheets(Mn-NTO@C)are syn-thesized by a one-step salt-template-assisted method,showing much-enhanced power *** as-prepared Mn-NTO@C demonstrates the realization of hybrid energy storage,which reconciles the diffusion-controlled behavior with the pseudocapacitive-controlled *** has been revealed that the Mn heteroatoms can raise the proportion of Na_(2)Ti_(3)O_(7) phase with the expanded crystal lattice,facilitating the diffusion-controlled insertion/extraction process of sodium ***,the hybrid morphology of Mn-NTO nanowires and carbon nanosheets provides a promoted structure ***,theassem-bled Na||Mn-NTO@C half-cells work well at an extreme current density of 24 A g^(−1) for 10000 cycles with a capacity retention of 95.2%.Moreover,the Mn-NTO@C||Na _(3) V_(2)(PO_(4))_(3)(NVP)full cells exhibit an attenuation of only 0.0015%per cycle at 20 A g^(−1) for over 10000 cycles,and the energy density and power density of the full cells reachan ultrahigh level of 262 Wh kg−1 and 16.3 kW kg−1,respectively.

关键词： carbon nanosheets hybrid energy storage Mn-doping,rate capability

Contact engineering for two-dimensional semiconductors

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Journal of Semiconductors 2020年第7期41卷 7-22页

作者： Peng Zhang Yiwei Zhang Yi Wei huaning jiang Xingguo Wang Yongji Gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Organic–Inorganic Composites Beijing Key Laboratory of Electrochemical Process and Technology for MaterialsBeijing University of Chemical TechnologyBeijing 100029 China

Two-dimensional(2D)layered materials,including graphene,black phosphorus(BP)and transition metal dichalcogenide(TMD)such as molybdenum disulfide(Mo S2),tungsten diselenide(WSe2),have attracted increasing attention for the application in electronic and optoelectronic ***,which are the communication links between these 2D materials and external circuitry,have significant effects on the performance of electronic and optoelectronic ***,the performance of devices based on 2D semiconductors(SCs)is often limited by the ***,we provide a comprehensive overview of the basic physics and role of contacts in 2D SCs,elucidating Schottky barrier nature and Fermi level pinning effect at metal/2D SCs contact *** progress of contact engineering,including traditional metals contacts and metallic 2D materials contacts,for improving the performance of 2D SCs based devices is *** metal contacts,named 3D top and edge contacts,are discussed ***,methods of building 2D materials contacts(2D top contact and 2D edge contact)are discussed in detail,such as chemical vapor deposition(CVD)growth of 2D metallic material contacts,phase engineered metallic phase contacts and intercalation induced metallic state ***,the challenges and opportunities of contact engineering for 2D SCs are outlined.

关键词： two-dimensional materials contact engineering Schottky barrier Fermi level pinning heterostructures

Epitaxial growth of metal-semiconductor van der Waals heterostructures NbS2/MoS2 with enhanced performance of transistors and photodetectors

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Science China Materials 2020年第8期63卷 1548-1559页

作者： Peng Zhang Ce Bian Jiafu Ye Ningyan Chen Xingguo Wang huaning jiang Yi Wei Yiwei Zhang Yi Du Lihong Bao Weida Hu Yongji Gong School of Materials Science and Engineering Beihang UniversityBeijing 100191China Institute of Physics&University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083China Institute for Superconducting and Electronic Materials(ISEM) Australian Institute for Innovation Materials(AIIM)University of WollongongNSW 2522Australia State Key Laboratory of Organic-Inorganic Composites Beijing Key Laboratory of Electrochemical Process and Technology for MaterialsBeijing University of Chemical TechnologyBeijing 100029China Beihang-UOW Joint Research Centre and School of Physics Beihang UniversityBeijing 100191China Songshan Lake Materials Laboratory Dongguan 523803China

Two-dimensional(2D)heterostructures based on layered transition metal dichalcogenides(TMDs)have attracted increasing attention for the applications of the nextgeneration high-performance integrated electronics and *** various TMD heterostructures have been successfully fabricated,epitaxial growth of such atomically thin metal-semiconductor heterostructures with a clean and sharp interface is still *** addition,photodetectors based on such heterostructures have seldom been ***,we report the synthesis of high-quality vertical NbS2/MoS2metallic-semiconductor *** using NbS2as the contact electrodes,the field-effect mobility and current on-off ratio of MoS2can be improved at least 6-fold and two orders of magnitude compared with the conventional Ti/Au contact,*** using NbS2as contact,the photodetector performance of MoS2is much improved with higher responsivity and less response *** facile synthesis of atomically thin metal-semiconductor heterostructures by a simple chemical vapor deposition strategy and its effectiveness as ultrathin 2D metal contact open the door for the future application of electronics and optoelectronics.

关键词： metal-semiconductor heterostructures contact engineering field-effect transistor photodetector

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岩石化学风化力学特性的宏微观定量关联

同济大学学报（自然科学版） 2024年第6期52卷 911-919页

作者：周志豪王华宁蒋明镜同济大学土木工程学院上海200092 同济大学航空航天与力学学院上海200092 同济大学土木工程防灾国家重点实验室上海200092 苏州科技大学土木工程学院江苏苏州215009

为了分析化学风化对岩石力学性能的影响机制,采用密集排列的颗粒集合体模拟岩石材料,将与化学风化时间相关的质量损失率引入颗粒刚度和胶结模型。基于均匀化方法和格构模型,推导获得了风化岩石弹性阶段应力‒应变关系和强度准则以及宏观... 详细信息

为了分析化学风化对岩石力学性能的影响机制,采用密集排列的颗粒集合体模拟岩石材料,将与化学风化时间相关的质量损失率引入颗粒刚度和胶结模型。基于均匀化方法和格构模型,推导获得了风化岩石弹性阶段应力‒应变关系和强度准则以及宏观弹性和强度参数与微观参数(颗粒接触响应特性、风化损伤参数等)的定量关联,并探究了化学风化及其时效性对岩石力学性能的影响规律。结果表明,随着质量损失率的增大以及反应时间的增加,风化岩石的刚度和强度均呈负指数减小;当环境pH值较低时,岩石的峰值黏聚力和峰值内摩擦角随着反应时间的增大均显著降低;当环境pH值较高时,开始阶段岩石的峰值黏聚力显著降低,而峰值内摩擦角变化不大,峰值内摩擦角的显著降低需要更长的风化时间。

关键词：岩石化学风化宏微观时效效应

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二维材料范德华间隙的利用

物理化学学报 2021年第11期37卷 19-34页

作者：阙海峰江华宁王兴国翟朋博孟令佳张鹏宫勇吉北京航空航天大学材料科学与工程学院北京100191

二维材料因为其优异且可调的各种物理化学性质自被发现以来就引起了科研工作者的极大关注。其电学、光学、量子、催化等方面的一些独特性质使其迅速成为一类极其重要的材料体系。二维材料层间弱结合的性质为利用范德华间隙来调控体系的... 详细信息

二维材料因为其优异且可调的各种物理化学性质自被发现以来就引起了科研工作者的极大关注。其电学、光学、量子、催化等方面的一些独特性质使其迅速成为一类极其重要的材料体系。二维材料层间弱结合的性质为利用范德华间隙来调控体系的电子结构从而进一步优化材料性能创造了条件。客体原子的引入可以显著改变原有材料的层间间距,改变层间的耦合强度。客体与宿主原子的相互作用也可能改变原始材料的电子结构,从而影响材料的多方面性能,甚至带来新的性质。以锂离子电池为代表的层间存储也是二维范德华间隙在能源存储方面的重要应用,一直受到许多科研工作者的关注。在本综述中,我们从利用插层法改变层间距从而改变层间耦合,引入客体物质与宿主原子相互作用从而改变原材料的物理化学性质或引入新性质和层间储能四个方面系统化阐述了二维材料范德华间隙的各种调控方法及其对合成材料的物理、化学性能的巨大影响,并展望了二维范德华间隙进一步开发利用的方向。

关键词：二维材料范德华间隙插层技术层间相互作用性能优化能源存储

DEM investigation of rock/bolt mechanical behaviour in pull-out tests

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Particuology 2020年第5期18卷 10-27页

作者： Na Che huaning Wang Mingjing jiang School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Department of Oivil Engineering Tianjin UniversityTianjin 300072China

Rock bolt anchorage performance is crucial for tunnel support *** investigate the mechanical behaviour of reinforced rock and the bolts that reinforce it from the micro-scale to the *** pull-out tests were performed on soft rock using the distinct element method,in which a new contact model that considers bond size,is employed to constrain the main rock mechanical *** minimum sample width and height values for which the boundary effect can be neglected are first proposed through numerous tests on the influence of sample size on peak load and bond *** influence of sample width is substantially greater than that of sample *** then select an appropriate sample size to study the influence of bolt embedment length and confining pressure on the mechanical behaviours of the rock and *** results show that increased rock bolt embedment length and confining pressure can increase the peak load;however,the bolt length effect is limited when exceeding the critical anchorage *** cases without confining pressure,bond breakage occurs in the rock around the grout-rock interface and the breakage zone is rectangular,whereas in cases under confining pressure,the breakage zone presents an inverted cone *** use our results to discuss the influence of bond strength at the bolt-grout interface on the peak load and failure *** failure mode changes gradually from complex failure to single failure along the bolt-grout interface with decreasing interfacial bond strength.

关键词： Pull-out test Rock bolt Distinct element method Bolt embedment length Confining pressure

Seepage flow around twin circular tunnels in anisotropic ground revealed by an analytical solution

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Underground Space 2023年第3期10卷 1-14页

作者： Fengran Wei huaning Wang Guangshang Zeng Mingjing jiang School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China School of Urban Construction and Safety Engineering Shanghai Institute of TechnologyShanghai 201418China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

A new analytical solution is proposed for steady seepage flow around twin circular tunnels in fully saturated anisotropic *** solution is an exact one that fully satisfies all the boundary conditions and precisely considers the different permeabilities along two direc-tions and the interactions between twin *** solution provides a fast approach for the estimation of the seepage field and a useful tool for design *** solution is successfully addressed using problem equivalence and the Schwartz alternating method com-bined with a mapping *** a coordinate transformation of the governing equation,the anisotropic problem of circular tunnels is first equivalent to that of isotropic elliptical tunnels,and the length of the ellipse along the anisotropic axis depends on the anisotropic permeability *** Schwartz alternating method is then employed to address the solution of equivalent elliptical twin tunnel prob-lems,where a mapping function,with which an elliptical tunnel in the half-plane can be mapped into an annulus in the image plane,is introduced to solve the single tunnel problems in each iterative *** iterative procedure is quite simple and efficient in its calculations and achieves good convergence,and the analytical solution agrees very well with the numerical results to reflect its high precision in the entire ***,parametric studies are performed to investigate the influences of the anisotropic permeability and tunnel spacing on the seepage *** is the first study to provide the exact analytical solution of the seepage field of twin tunnel problems in aniso-tropic ground,and the procedure can be extended to multiple tunnel problems.

关键词： Underwater tunnel Seepage field Anisotropy Schwartz alternating method Conformal mapping method