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Mandrel degradation model of combined fast and slow processes

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High Power Laser Science and Engineering 2021年第1期9卷 1-7页

作者： Yu Zhu Zheng Liu Famin Yu Qiang Chen Wei Feng Zhanwen Zhang Zhigang Wang Institute of atomic and Molecular Physics Jilin UniversityChangchun 130012China Laser Fusion Research Center China Academy of Engineering PhysicsMianyang 621900China

In this paper, we report the study of degradation for a kind of ideal mandrel material called poly-α-methylstyrene based on theoretical and experimental methods. First-principles calculations reveal two types of process: depolymerization and hydrogen-transfer-induced chain scission. The energy barrier for the former(0.68–0.82 eV) is smaller than that for most of the latter(1.39–4.23 eV). More importantly, reaction rates suggest that the former is fast whereas the latter is mostly slow, which can result in a difference of 5–31 orders of magnitude at 550 K. Furthermore, a thermogravimetric experiment shows that the activation energy of 2.53 eV for degradation is between those of fast and slow processes,corresponding to the theoretical average value of multiple reaction paths. Thus, a mandrel degradation model combining fast and slow processes is established at the atomic level. Our work provides a direction for research into the key technology of target fabrication in inertial confinement fusion.

关键词： atomic level degradation first principles mandrel material thermogravimetric experimenth

Bottom-up design and assembly with superatomic building blocks

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Chinese Physics B 2022年第12期31卷 613-617页

作者： Famin Yu Zhonghua Liu Jiarui Li Wanrong Huang Xinrui Yang Zhigang Wang Institute of atomic and Molecular Physics Jilin UniversityChangchun 130012China College of Physics Jilin UniversityChangchun 130012China Institute of Theoretical Chemistry College of ChemistryJilin UniversityChangchun 130023China

Constructing specific structures from the bottom up with artificial units is an important interdisciplinary topic involving physics,chemistry,materials,and so *** this work,we theoretically demonstrated the feasibility of using superatoms as building blocks to assemble a complex at atomic-level *** using a series of actinide-based endohedral metallofullerene(EMF)superatoms that can form one,two,three and four chemical bonds,a planar complex with intra-and inter-molecular interactions was assembled on the Au(111)*** complex is composed of two parts,containing ten and eight superatoms,*** electronic structure analysis shows that the electron density inside each part is connected and the closed-shell electronic arrangement system is *** is also an obvious van der Waals boundary by physical adsorption between the two parts,and a stable complex is *** this complex is realized by the first-principles calculations of quantum mechanics,our results help not only achieve atomic-level precision construction with artificial superatomic units but also maintain atomic-level functional properties.

关键词： superatom bottom-up assembly atomic level

Atom elimination strategy for MoS_(2) nanosheets to enhance photocatalytic hydrogen evolution

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Chinese Chemical Letters 2023年第3期34卷 138-141页

作者： Xia Liu Yunhui Hou Meng Tang Longlu Wang College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

The regulation of the basic properties of atom-economic catalysts at the atomic scale and atomic-level insights into the underlying mechanism of catalysis are less explored. We engineer the surface of vertical immobilized MoS_(2) on dispersible TiO_(2) nanofibers via atomic subtraction to precisely manipulate active sites at the atomic level. The photocatalytic performances of TiO_(2) @MoS_(2) after H_(2) reduction towards the hydrogen production under visible light irradiation(>420 nm) are about 4 times that of TiO_(2) @MoS_(2) before H_(2) reduction. Importantly, the enhanced stability of TiO_(2) @MoS_(2) lasts for at least 30 h. Promising catalytic activity that is attributed to omnidirectional exposed active sites located defects, edges, corners that are transformed from the subtractive atomic sites could be exhumed comprehensively. This work will provide an intriguing and effective approach on tuning electronic structures for optimizing the catalytic activity at the atomic level by atom elimination strategy. To get rid of a few atomics on the surface of atomically-thin MoS_(2) nanosheet could be a prudent avenue for enabling the basal plane of MoS_(2) catalytically active.

关键词： atomic level Defect MoS_(2)nanosheets Photocatalysis Hydrogen evolution

Visible-Light-Driven Methane Conversion with Oxygen Enabled by atomically Precise Nickel Catalyst

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CCS Chemistry 2021年第9期3卷 2509-2519页

作者： Weigang Hu Yongnan Sun Shuohao Li Xinglian Cheng Xiao Cai Mingyang Chen Yan Zhu School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210093 Center for Green Innovation School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083 Shunde Graduate School University of Science and Technology BeijingFoshan 528000

It remains an extreme challenge to activate thermodynamically unfavorable,chemically inert methane molecules under mild ***,we report a molecular-like nickel-thiolate hexameric cluster[Ni_(6)(PET)_(12);PET=SC_(2)H_(4)Ph]catalyst that resembles a double crown,comprising of a hexagonal Ni6 kernel encapsulated by an exterior shell of 12 thiolates capable of efficient conversion of methane plus O_(2) to methanol and formic acid under visible light irradiation.

关键词： CH_(4) O_(2) atomic level nanocluster chemicals