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Targeted bottom-up synthesis of 1T-phase MoS2 arrays with high electrocatalytic hydrogen evolution activity by simultaneous structure and morphology engineering

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Nano Research 2018年第8期11卷 4368-4379页

作者： Kaian Sun Yunqi Liu Yuan Pan Houyu Zhu Jinchong Zhao Lingyou Zeng Zhi Liu Chenguang Liu State Key Laboratory of Heavy Oil Processing College of Chemical Engineering China University of Petroleum (East China) 66 WestChangjiang Road Qingdao 266580 China Department of Chemistry Tsinghua University Beijing 100084 China College of Science China University of Petroleum (East China) 66 West Changjiang Road Qingdao 266580 China

The incorporation of small guest molecules or ions by bottom-up hydrothermal synthesis has recently emerged as a promising new way to engineer 1T-phase MoS2 with high hydrogen evolution reaction （HER） activity. However, the mechanism of the associated structural evolution remains elusive and controversial, leading to a lack of effective routes to prepare 1T-phase MoS2 with controlled structure and morphology, along with high purity and stability. Herein, urea is chosen as precursor of small molecules or ions to simultaneously engineer the phase （16.4%, - 69.4%, and -90.2% of 1T phase） and size （98.8, - 151.6, and - 251.8 nm for the 90.2% 1T phase） of MoS2 nanosheets, which represent an ideal model system for investigating the structural evolution in these materials, as well as developing a new type of 1T-phase MoS2 arrays. Using reaction intermediate monitoring and theoretical calculations, we show that the oriented growth of 1T-phase MoS2 is controlled by ammonia-assisted assembly recrystallization, and stabilization processes. A superior HER performance in acidic media is obtained, with an overpotential of only 76 mV required to achieve a stable current density of 10 ***-2 for 15 h. This excellent performance is attributed to the unique array structure, involving well-dispersed, edge-terminated, and high-purity 1T-phase MoS2 nanosheets.

关键词： molybdenum disulfide bottom-up synthesis morphology engineering.structure engineering hydrogen evolution density functional theory

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Chevron-type graphene nanoribbons with a reduced energy band gap:Solution synthesis,scanning tunneling microscopy and electrical characterization

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Nano Research 2020年第6期13卷 1713-1722页

作者： Ximeng Liu Gang Li Alexey Lipatov Tao Sun Mohammad Mehdi Pour Narayana R.Aluru Joseph W.Lyding Alexander Sinitskii Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-ChampaignUrbanaIL61801USA Department of Electrical and Computer Engineering University of Illinois at Urbana-ChampaignUrbanaIL61801USA Department of Chemistry University of Nebraska-LincolnLincolnNE68588USA Department of Mechanical Science and Engineering University of Illinois at Urbana-ChampaignUrbanaIL61801USA Nebraska Center for Materials and Nanoscience University of Nebraska-LincolnLincolnNE68588USA

Graphene nanoribbons(GNRs)attract a growing interest due to their tunable physical properties and promise for device applications.A variety of atomically precise GNRs have recently been synthesized by on-surface and solution *** on-surface GNRs can be conveniently visualized by scanning tunneling microscopy(STM),and their electronic structure can be probed by scanning tunneling spectroscopy(STS),such characterization remains a great challenge for the solution-synthesized ***,we report solution synthesis and detailed STM/STS characterization of atomically precise GNRs with a meandering shape that are structurally related to chevron GNRs but have a reduced energy band *** ribbons were synthesized by Ni0-mediated Yamamoto polymerization of specially designed molecular precursors using triflates as the leaving groups and oxidative cyclodehydrogenation of the resulting polymers using Scholl *** ribbons were deposited onto III-V semiconducting InAs(110)substrates by a dry contact transfer ***-resolution STM/STS characterization not only confirmed the GNR geometry,but also revealed details of electronic structure including energy states,electronic band gap,as well as the spatial distribution of the local density of *** experimental STS band gap of GNRs is about 2 eV,which is very close to 2.35 eV predicted by the density functional theory simulations with GW correction,indicating a weak screening effect of InAs(110)***,several aspects of GNR-InAs(110)substrate interactions were also probed and analyzed,including GNR tunable transparency,alignment to the substrate,and manipulations of GNR position by the STM *** weak interaction between the GNRs and the InAs(110)surface makes InAs(110)an ideal substrate for investigating the intrinsic properties of *** of the reduced energy band gap of these ribbons,the GNR thin films exhibit appreciably high electrical conductivity and on/off ratios of about 1

关键词： graphene nanoribbons bottom-up synthesis electronic structure dry contact transfer scanning tunneling microscopy scanning tunneling spectroscopy

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Room temperature synthesis of two-dimensional multi layer magnets based on α-Co^(Ⅱ) layered hydroxides

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Nano Materials Science 2022年第1期4卷 36-43页

作者： Victor Oestreicher Christian Dolle Diego Hunt Michael Fickert Gonzalo Abellan Instituto de Ciencia Molecular(ICMol).Universidad de Valencia Catedritico Jose Beltran 2PaternaValencia46980Spain Departamento de Física de la Materia Condensada GIy A.Instituto de Nanociencia y NanotecnologíaCNEA-CAC-CONICET.Av.Gral.PazSan MartinBuenas Aires1650Argentina Chair of Organic ChemistryⅡand Joint Institute of Advanced Materials and Processes(ZMP).Friedrich-Alexander-Universitát Erlangen-Nürnberg(FAU) Nikolaus-Fiebiger Strasse 1091058 Erlangen and Dr.-Mack Strasse 81Furth 90762Germany

Research on two-dimensional(2D) materials is one of the most active fields in materials science and nanotechnology. Among the members of the 2D family, layered hydroxides(LHs) represent an exceptional case of study due to their unparalleled chemical versatility which allows the modulation of their physicochemical properties at will. Nowadays, LHs based on earth-abundant metals are key materials in the areas of energy storage and conversion, hybrid materials or magnetism. α-Co hydroxides(Simonkolleite-like structures) are promising phases with tuneable electronic and magnetic properties by ligand modification. However, even in the simple case of α-Co^(Ⅱ) hydroxychlorides, the preparation of well-defined large 2D crystals is not straightforward, hindering the development of fundamental studies. Herein, we present the synthesis of 2D hexagonal crystals with outstanding sizethickness relationship(diameter > 5 μm and thickness of 20 ± 7 nm) by a simple homogeneous synthesis taking place at room temperature. In structural terms, no differences are observed between our layered materials and those obtained hydrothermally. However, dynamic susceptibility measurements alert about different arrangements of the magnetic sublattices, which have been rationalized with structural DFT calculations. This work provides an extremely easy bottom-up method to obtain high-quality 2D crystals based on α-CoIIhydroxides,paving the way for the development of fundamental studies and applications.

关键词： Two-dimensional(2D)materials Layered hydroxides Hexagonal morphology bottom-up synthesis Magnetism

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Synthetic Strategies for Constructing Two-Dimensional Metal-Organic Layers （MOLs）： A Tutorial Review

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Chinese Journal of Chemistry 2018年第8期36卷 754-764页

作者： Lingyun Cao Tingting Wang Cheng Wang Collaborative Innovation Center of Chemistry for Energy Materials State Key Laboratory of Physical Chemistry of Solid Surfaces Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University Xiamen Fujian 361005 China

Two-dimensional （2D） metal-organic layers （MOLs） are the 2D version of metal-organic frameworks （MOFs） with nanometer thickness in one dimension. MOLs are also known as 2D-MOFs, 2D coordination polymers, ultrathin MOF nanosheets （UMOFNs） or coordination nanosheets in literature. This new category of 2D materials has attracted a lot of interests because of the opportunity in combining molecular chemistry, surface/interface chemistry and material chemistry of low dimensional materials in these systems. Several synthetic strategies have been developed for the construction of 2D MOLs, but the general synthesis of MOLs still presents a challenge. This tutorial level review summarizes the recent progress in the fabrication of novel 2D MOLs and aims to highlight challenges in this field.

关键词： metal-organic layers metal-organic frameworks 2D materials bottom-up synthesis top-down synthesis

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Synthetic Strategies of Carbon Nanobelts and Beyond

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Chemical Research in Chinese Universities 2024年第4期40卷 627-631页

作者： LI Yanbang SHANG Wansong REN Yu ZHANG Xi-Sha LI Cheng ZHANG Guanxin ZHANG Deqing Beijing National Laboratory for Molecular Science CAS Key Laboratory for Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing100190P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

Carbon nanobelts(CNBs)with aesthetically appealing molecular structures and outstanding physical properties have attracted more and more attentions from the scientific community due to their potential applications in synthetic materials,host-guest chemistry,optoelectronics,and so *** synthesis of CNBs at different stages was overviewed and some representative breakthroughs and advances in synthetic strategies were highlighted and *** key issue for the synthesis of CNBs is how to construct curved structures with high strain *** not only proposed a few unconventional CNBs as the promising target molecules,but also pointed out the bottom-up synthesis of conjugated tubular segments of carbon nanotubes sharing similar properties as carbon nanotubes is the next focus in this emerging area.

关键词： Carbon nanobelt Strain energy Carbon nanoring Single-walled carbon nanotube bottom-up synthesis

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Metal-organic framework nanosheets and their composites for heterogeneous thermal catalysis:Recent progresses and challenges

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Chinese Chemical Letters 2021年第11期32卷 3307-3321页

作者： Chengqian Cui Guodong Li Zhiyong Tang CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049China

Metal-organic framework nanosheets(MONs)as the emerging materials have been attracting great interest because the nanosheets possess a range of fascinating attributes including high surface areas and sufficient accessible active sites,and their nanoscale thicknesses are favorable for mass diffusion and transfer of substrates and products with respect to bulk metal-organic frameworks(MOFs).This review first summarizes the synthetic methods of various MONs from top-down and bottom-up methods as well as their diverse composites with different ***,the catalytic applications of MON based nanocatalysts are discussed and the relationships among the composition,structure and catalytic performances are ***,the challenges and future outlook about the synthesis of diverse MONs and their composites for heterogeneous catalysis are prospected.

关键词： Metal-organic framework nanosheet Top-down synthesis bottom-up synthesis Composite structure Heterogeneous catalysis

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