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SSRN 2024年

作者： Zhao, Yang Bao, Luyao Fan, Xiaoli Zhou, Feng State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal Materials School of Materials Science and Engineering Northwestern Polytechnical University Xi’an710072 China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou730000 China Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai264006 China

Here we find the general and abnormal stick-slip friction of nanoconfined water by extensive molecular dynamics simulations. Specifically, water films exhibit general stick-slip behavior when confined below 1 nm, independent of the water phase, surface wettability, and solid lattice structure. However, at confinement distances of 0.7 and 0.9 nm water films are in liquid-like states, which contradicts the common belief that only solid-like lubricant films can produce stick-slip friction. This unexpected behavior is attributed to the nature of short-time-scale ordered but long-time-scale disordered. Further, we reveal the velocity dependence of friction, which is mainly linear at >= 1 nm, logarithmic at 0.8-0.9 nm, and plateau-like at 0.6-0.7 nm, and give theoretical descriptions by extending the Kramer's theory of activated processes. © 2024, The Authors. All rights reserved.

关键词： Shear thinning

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Structure design enables stable anionic and cationic redox chemistry in a T2-type Li-excess layered oxide cathode

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science Bulletin 2022年第4期67卷 381-388,M0004页

作者： Xin Cao Haifeng Li Yu Qiao Min Jia Hirokazu Kitaura Jianan Zhang Ping He Jordi Cabana Haoshen Zhou Energy Technology Research Institute National Institute of Advanced Industrial Science and Technology(AIST)Tsukuba 305-8568Japan Department of Chemistry University of Illinois at ChicagoChicagoIL 60607USA Center of Energy Storage Materials&Technology College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional MaterialsNational Laboratory of Solid State Microstructuresand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China Graduate School of System and Information Engineering University of TsukubaTsukuba 305-8573Japan College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

Coupled with anionic and cationic redox chemistry,Li-rich/excess cathode materials are prospective high-energy-density candidates for the next-generation Li-ion ***,irreversible lattice oxygen loss would exacerbate irreversible transition metal migration,resulting in a drastic voltage decay and capacity ***,a metastable layered Li-excess cathode material,T2-type Li_(0.72)[Li_(0.12)Ni_(0.36)Mn_(0.52)]O_(2),was developed,in which both oxygen stacking arrangement and Li coordination environment fundamentally differ from that in conventional O3-type layered *** means of the reversible Li migration processes and structural evolutions,not only can voltage decay be effectively restrained,but also excellent capacity retention can be achieved upon long-term ***,irreversible/reversible anionic/cationic redox activities have been well assigned and quantified by various in/ex-situ spectroscopic techniques,further clarifying the charge compensation mechanism associated with(de)*** findings of the novel T2 structure with the enhanced anionic redox stability will provide a new scope for the development of high-energy-density Li-rich cathode materials.

关键词： Cathode materials Layered oxides Voltage decay Lattice oxygen release Structural stability

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Ternary Ni:Fe- Activated Inert Cu-Based Electrocatalyst as Efficient Bifunctional Electrocatalysts for Water Splitting

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SSRN 2024年

作者： Lu, Shi-Yu Wu, Chunjie Hu, Tingting Wang, Ling Dou, Wenzhao Zhang, Jun Wang, Rong Liu, Yin Yang, Qian Jin, Meng Zou, Zhigang College of Materials and New Energy Chongqing University of Science and Technology Chongqing401331 China College of Chemistry and Chemical Engineering Chongqing University of Science and Technology Chongqing401331 China Collaborative Innovation Center of Advanced Microstructures National Laboratory of Solid State Microstructures College of Engineering and Applied Sciences Nanjing University Jiangsu Nanjing210093 China Peking University China

Cost-effective copper-based materials with their abundant reserves, good electrical conductivity, and a wide range of redox properties that are promising for the electrochemical energy field, but they exhibit inertness and slow reaction kinetics for electrocatalysis. Therefore, improving the catalytic activity of Cu is prospective but still challenging. Herein, we developed a Ni and Fe-doped CuO/Cu2O heterojunction catalyst with oxygen vacancies, which presented distinguished bifunctional catalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. Remarkably, the adsorption/desorption energy of H2O on surface of the catalyst had been definitely demonstrated via theoretical calculation and experiments, indicating that Fe, Ni bimetallic activated the inertness of the Cu-based materials. Fe doped corroded the Cu substrate and induced more oxygen vacancies, thereby increasing the electrochemically active area and ultimately enhancing the catalytic performance of the overall catalyst. Consequently, the cell voltage of Ni:Fe-CuO/Cu2O catalysts for a current density of 10 mA·cm−2 in an alkaline electrolyzer was just 1.51 V, and it exhibited an excellent stability. In addition, the cell voltage of the electrolyzer at of 10 mA·cm−2 was just 1.30 V in simulated industrial hydrogen production via water electrolysis, and the current density can be as high as 1.8 A·cm−2 at a voltage of 2.5 V. This study highlights the significant impact of electronic structure modulation and oxygen vacancies on copper-based catalysts, greatly enhancing the electrocatalytic activity of inert copper. © 2024, The Authors. All rights reserved.

关键词： Redox reactions

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Scaling Up to Macroscale Superlubricity of Sp2-Dominated Structural Carbon Films: Graphene and Carbon Onion

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SSRN 2023年

作者： Yang, Xing Wang, Yongfu Zhang, Junyan State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Science Lanzhou730000 China Key Laboratory of Science and Technology on Wear and Protection of Materials Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou730000 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China

sp2-dominated structural carbon films can exhibit macroscale superlubricity. Nevertheless, the mechanisms governing the superlubricity are still not well comprehended, mainly due to the link lack of the relevance between graphene (or carbon onion) and superlubricity scale-up. Here, we establish the link by the combination of atomic force microscopy (AFM), transmission electron microscopy (TEM) and Raman analyses of the frictional surfaces of sp2-dominated structural carbon films. The friction-induced graphene and carbon onion products locate strictly at the wear track center and take on flake-like and nanoparticle-like morphologies, respectively. Then they can eliminate the cross-interface carbon-carbon interactions and reduce contact area, thereby promoting the achievement of macroscale superlubricity. Atomistic simulations reveal the key role of the curvature and cross-linking degree of graphene basal planes in the sp2-dominated carbon films on their frictional products. The results answer the question how the nanoscale tribology of graphene and carbon onion can be scaled up to macroscale superlubricity. © 2023, The Authors. All rights reserved.

关键词： Graphene

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Mxene/Metal–Organic Framework Based Composite Coating with Photothermal Self-Healing Performances for Antifouling Application

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SSRN 2023年

作者： Wang, Peng He, Baoluo Wang, Biwen Liu, Shujuan Ye, Qian Zhou, Feng Liu, Weimin State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal Materials School of Materials Science and Engineering Northwestern Polytechnical University Xi’an710072 China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou730000 China

Antifouling coatings have been widely utilized to prevent microbial attachment. However, these coatings can be damaged and lose their effectiveness, leading researchers to develop coatings that can self-heal. In this study, a novel metal-organic framework (MZ-8) based on mercaptobenzothiazole (MBT) was successfully synthesized by forming coordination bonds with 2-methylimidazole and zinc salt. The MZ-8 was then combined with Ti3C2TX nanosheets (MXene) to create an organic-inorganic nanocomposite (MZ-8/MXene), which was used as a filler for polyurethane (PU) resin. The resulting MZ-8/MXene/PU coating exhibited a remarkable ability to convert near-infrared laser (NIR) light into heat, enabling the PU resin to melt and flow, thereby efficiently repairing mechanical damage with over 92% effectiveness. Additionally, the MZ-8/MXene/PU coating reduced microbial adhesion through the photothermal effect and the release of zinc ions and MBT, achieving a reduction of more than 99% in surface-attached bacteria and 93% in microalgae. Moreover, the coating demonstrated good anti-corrosion properties by inhibiting the penetration of corrosive substances, thanks to the protective film formed by MBT and the shielding properties of layered MXene. This study presents a novel approach to develop coatings with both antifouling and self-healing capabilities, offering wide-ranging applications in fields such as marine antifouling and biomedical instruments. © 2023, The Authors. All rights reserved.

关键词： Infrared devices

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Kinetic Investigation of a Cucurbituril-Based Pseudorotaxane System by Microfluidic Nuclear Magnetic Resonance

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CCS Chemistry 2022年第2期4卷 557-565页

作者： Yibin Sun Hongxun Fang Xujing Lin Xiuxiu Wang Ganyu Chen Xinchang Wang Zhongqun Tian Liulin Yang Marcel Utz Xiaoyu Cao State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringCollaborative Innovation Center of Chemistry for Energy Materials(iChEM)Key Laboratory of Chemical Biology of Fujian ProvinceXiamen UniversityXiamen 361005 School of Electronic Science and Engineering(National Model Microelectronics College) Xiamen UniversityXiamen 361005 School of Chemistry University of SouthamptonSouthampton SO171BJ

It is challenging to investigate fast supramolecular processes due to the lack of appropriate characterization methods with high structural *** this study,microfluidic nuclear magnetic resonance(μFNMR)spectroscopy was employed to monitor the kinetics of threading and dethreading of a pseudo[6]rotaxane *** employing high time resolutionμF-NMR,1 H and two-dimensional(2D)rotating frame nuclear Overhauser effect spectroscopy(ROESY)NMR spectra were recorded at any time point within 1.5 s after the onset of the *** technique enabled the successful identification of kinetic intermediates and rate-determining steps,usually impossible to determine by other spectroscopic ***,our study demonstrates the capability ofμF-NMR in investigating the mechanism of complex supramolecular systems.

关键词： host-guest chemistry kinetics cucurbit[7]uril β-cyclodextrin microfluidic NMR

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Strongly coupled magneto-exciton condensates in large-angle twisted double bilayer graphene

arXiv

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arXiv 2024年

作者： Li, Qingxin Chen, Yiwei Wei, LingNan Chen, Hong Huang, Yan Zhu, Yujian Zhu, Wang An, Dongdong Song, Junwei Gan, Qikang Zhang, Qi Watanabe, Kenji Taniguchi, Takashi Shi, Xiaoyang Novoselov, Kostya S. Wang, Rui Yu, Geliang Wang, Lei National Laboratory of Solid-State Microstructures School of Physics Nanjing University Nanjing210093 China Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Department of Earth and Environmental Engineering Columbia University New YorkNY10027 United States Institute for Functional Intelligent Materials National University of Singapore Building S9 4 Science Drive 2 Singapore117544 Singapore

Excitons, the bosonic quasiparticle emerging from Coulomb interaction between electrons and holes, will undergo a Bose-Einstein condensation(BEC) and transition into a superfluid state with global phase coherence at low temperatures. An important platform to study such excitonic physics is built on double-layer quantum wells or recent two-dimensional material heterostructures, where two parallel planes of electrons and holes are separated by a thin insulating layer. Lowering this separation distance (d) enhances the interlayer Coulomb interaction thereby strengthens the exciton binding energy. However, an exceedingly small d will lead to the undesired interlayer tunneling, which results the annihilation of excitons. Here, we report the observation of a sequences of robust exciton condensates(ECs) in double bilayer graphenes twisted to ∼10° with no insulating mid-layer. The large momentum mismatch between the two graphene layers well suppress the interlayer tunneling, allowing us to reach the separation lower limit ∼ 0.334 nm and investigate ECs in the extreme coupling regime. Carrying out transport measurements on the bulk and edge of the devices, we find incompressible states corresponding to ECs when both layers are half-filled in the N = 0 and N = 1 Landau levels (LLs). The comparison between these ECs and theoretical calculations suggest that the low-energy charged excitation of ECs can be meron-antimeron or particle-hole pair, which relies on both LL index and carrier type. Our results establish large-angle twisted bilayers as an experimental platform with extreme coupling strength for studying quantum bosonic phase and its low-energy excitations. © 2024, CC BY.

关键词： Excitons

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Electrically tunable layer-hybridized trions in doped WSe2 bilayers

arXiv

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arXiv 2024年

作者： Perea-Causin, Raul Brem, Samuel Buchner, Fabian Lu, Yao Watanabe, Kenji Taniguchi, Takashi Lupton, John M. Lin, Kai-Qiang Malic, Ermin Department of Physics Chalmers University of Technology Gothenburg Sweden Department of Physics Stockholm University Stockholm Sweden Department of Physics Philipps-Universität Marburg Marburg Germany Department of Physics University of Regensburg Regensburg Germany State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering Xiamen University Xiamen China Research Center for Electronic and Optical Materials National Institute for Materials Science Tsukuba Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science Tsukuba Japan

Doped van der Waals heterostructures host layer-hybridized trions, i.e. charged excitons with layerdelocalized constituents holding promise for highly controllable optoelectronics. Combining a microscopic theory with photoluminescence (PL) experiments, we demonstrate the electrical tunability of the trion energy landscape in naturally stacked WSe2 bilayers. We show that an out-of-plane electric field modifies the energetic ordering of the lowest lying trion states, which consist of layer-hybridized Λ-point electrons and layer-localized K-point holes. At small fields, intralayer-like trions yield distinct PL signatures in opposite doping regimes characterized by weak Stark shifts in both cases. Above a doping-asymmetric critical field, interlayer-like species are energetically favored and produce PL peaks with a pronounced Stark red-shift and a counter-intuitively large intensity arising from efficient phonon-assisted recombination. Our work presents an important step forward in the microscopic understanding of layer-hybridized trions in van der Waals heterostructures and paves the way towards optoelectronic applications based on electrically controllable atomically-thin semiconductors. Copyright © 2024, The Authors. All rights reserved.

关键词： Van der Waals forces

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Unveiling the molecule–plasmon interactions in surface-enhanced infrared absorption spectroscopy

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National science Review 2020年第7期7卷 1228-1238页

作者： Jun Yi En-Ming You Song-Yuan Ding Zhong-Qun Tian State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) and Department of Chemistry College of Chemistry and Chemical Engineering Xiamen University NSF Nanoscale Science and Engineering Center University of California

Nanostructure-based surface-enhanced infrared absorption(SEIRA) spectroscopy has attracted tremendous interest as an ultrasensitive detection tool that supplies chemical-fingerprint information. The interactions between molecular vibrations and plasmons lead to not only the enhancement of spectral intensity, but also the distortion of spectral Lorentzian lineshapes into asymmetric Fano-type or more complicated lineshapes in the SEIRA spectra; this effect hampers the correct readout of vibrational frequencies and intensities for an accurate interpretation of the measured spectra and quantitative *** this work, we investigate the Fano interference between molecular vibrations and plasmons based on exact electrodynamic simulations and theoretical models. We report that, even if the molecular vibrational energy is equal to the plasmon resonant energy, the molecule–nanostructure distance-dependent dipole–dipole interactions, the plasmon-mediated coherent intermolecular interactions and the decay rates of plasmons have a significant impact on the SEIRA lineshapes. This study paves the way for controllable Fano interference at the nanoscale and more studies on plasmon-dressed molecular electronic or vibrational excited states.

关键词： surface plasmons surface-enhanced infrared absorption Fano resonance coupling strength spectral lineshape

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Direct Capturing and Regulating Key Intermediates for High-Efficiency Oxygen Evolution Reactions

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Small Methods 2024年第9期8卷 e2301504页

作者： Qian, Zheng-Xin Peng, Chun-Kuo Yue, Mu-Fei Hsu, Liang-Ching Zeng, Ji-Shuang Wei, Di-Ye Du, Zi-Yu Xu, Ge-Yang Zhang, Hua Tian, Jing-Hua Chen, San-Yuan Lin, Yan-Gu Li, Jian-Feng College of Materials State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical Engineering iChEM Fujian Key Laboratory of Advanced Materials College of Energy Xiamen University Xiamen361005 China Department of Materials Science and Engineering National Yang Ming Chiao Tung University Hsinchu30010 Taiwan National Synchrotron Radiation Research Center Hsinchu30076 Taiwan Xiamen361005 China Department of Chemistry and Environment Science Fujian Province University Key Laboratory of Analytical Science Minnan Normal University Zhangzhou363000 China

Developing efficient oxygen evolution reaction (OER) electrocatalysts can greatly advance the commercialization of proton exchange membrane (PEM) water electrolysis. However, the unclear and disputed reaction mechanism and structure-activity relationship of OER pose significant obstacles. Herein, the active site and intermediate for OER on AuIr nanoalloys are simultaneously identified and correlated with the activity, through the integration of in situ shell-isolated nanoparticle-enhanced Raman spectroscopy and X-ray absorption spectroscopy. The AuIr nanoalloys display excellent OER performance with an overpotential of only 246 mV to achieve 10 mA cm−2 and long-term stability under strong acidic conditions. Direct spectroscopic evidence demonstrates that *OO adsorbed on IrOx sites is the key intermediate for OER, and it is generated through the O–O coupling of adsorbed oxygen species directly from water, providing clear support for the adsorbate evolution mechanism. Moreover, the Raman information of the *OO intermediate can serve as a universal "in situ descriptor" that can be obtained both experimentally and theoretically to accelerate the catalyst design. It unveils that weakening the interactions of *OO on the catalysts and facilitating its desorption would boost the OER performance. This work deepens the mechanistic understandings on OER and provides insightful guidance for the design of more efficient OER catalysts. © 2023 Wiley-VCH GmbH.

关键词： Raman spectroscopy

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