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Operando TEM Probes Dynamic Evolution of Transition Metal-Based Catalysts and Their Heterostructures

advanced functional Materials 2025年

作者： Yuan, Bo Zhu, Yuchen Liu, Shuhui Shan, Aixian Wang, Rongming Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science Academy for Advanced Interdisciplinary Science and Technology State Key Laboratory for Advanced Metals and Materials School of Mathematics and Physics University of Science and Technology Beijing Beijing100083 China School of Railway Intelligent Engineering Dalian Jiaotong University Liaoning Dalian116028 China

Transition metals-based catalysts and their heterostructures represent a critical category of catalytic materials, and understanding their catalytic mechanisms and achieving precise synthesis are of paramount importance. Operando transmission electron microscopy (TEM) enables real-time monitoring of sample responses to external stimuli, which is crucial for observing structural, compositional, and electronic changes in nanocatalysts during reactions and aids in designing efficient catalysts and establishing atomic-level structure-property relationships. This review discusses how operando TEM, with its high spatial and temporal resolution, enables real-time observation of critical phenomena such as nucleation, growth, sintering, and single-atom dispersion in nanocatalysts. The effects of external stimuli, including gas atmosphere, thermal, optical, and electrical fields, on the structural and chemical properties of catalysts are analyzed. Moreover, the application of operando TEM for real-time monitoring of structural evolution and external signal changes in catalysts under operating conditions is discussed, providing essential insights into the ‘black box’ of heterogeneous reactions. It is anticipated that these efforts will further facilitate the development of novel high-performance catalysts and deepen the understanding of material structure-performance relationships at a more profound level. © 2025 Wiley-VCH GmbH.

关键词： Iron

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Surface curvature regulation of 3D kirigami soft gripper

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International Journal of Solids and Structures 2025年 317卷

作者： Wu, Jian Yang, Bohan Li, Zhe He, Shixue Bu, Yingxuan Su, Benlong Wang, Youshan Center for Rubber Composite Materials and Structures Harbin Institute of Technology Weihai264209 China National Key Laboratory of Science and Technology On Advanced Composites in Special Environments Harbin Institute of Technology Harbin150090 China

Kirigami principles have been integrated into flexible grippers, exploiting the shape transforming advantages to improve the grippers’ performance and broaden the varieties upon which can be operated. However, few studies have adopted the 3D polygonal auxetic kirigami as the main structure of the gripper, due to its complex spatial design process, narrowed means of fabrication and multi-freedom actuation. Herein, gripper deformation based on auxetic kirigami under a simple actuation of 1-DoF is studied via an energy minimization framework. Firstly, a spring potential energy minimization problem of the 3D kirigami with geometric constraints is solved to obtain its deployment path and energy landscape. Then the deformed surface is analyzed using discrete Gauss-Bonnet theorem, proposing a method to regulate the shape morphing into the targets. Finite element analysis is used to verify the kirigami design framework and shape prediction. Finally, different types of kirigami grippers are fabricated and tested, achieving effective conformation and grasping of typically shaped objects, while exhibiting universal, easily actuated characteristics. These findings contribute to advancing the field of robotic handling and manipulation, particularly in applications requiring gentle and compliant interactions with diverse and specifically delicate objects. © 2025 Elsevier Ltd

关键词： Shape optimization

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Enhanced exciton dissociation through scandium-decorated conjugated polymers for artificial photosynthesis of hydrogen peroxide

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Journal of Energy Chemistry 2025年第4期103卷 714-722页

作者： Xingxing Chen Yongli Shen Fan Yang Shuang Yao Wen Zhang Baojuan Xi Xuguang An Shenglin Xiong Jinhua Ye Changhua An Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry and Chemical EngineeringTianjin Key Laboratory of Advanced Functional Porous MaterialsInstitute of New Energy Materials&Low-Carbon TechnologiesTianjin University of TechnologyTianjin 300384China School of Chemistry and Chemical Engineering Shandong UniversityJinan 250100ShandongChina School of Mechanical Engineering Chengdu UniversityChengdu 610106SichuanChina International Center for Materials Nanoarchitectonics(WPI-MANA) National Institute for Materials Science(NIMS)1-1 NamikiTsukubaIbaraki 305-0044Japan

Solar-driven hydrogen peroxide(H_(2)O_(2))production offers a sustainable and environmentally friendly alternative to the traditional anthraquinone oxidation *** polymers(CPs)are emerging as promising photocatalysts for H_(2)O_(2)production due to their unique electronic,optical properties,and tunable ***,the high exciton binding energy of CPs hinders efficient exciton dissociation and charge separation,limiting their photocatalytic *** this work,we synthesized scandium(Sc)atoms decorated CPs with enhanced ordered stacking and crystallinity by introducing benzaldehyde as an end-capping *** strong interaction between charged Sc atoms and electrons facilitates exciton dissociation and improves charge transfer ***,the Lewis acidic nature of Sc atoms promotes oxygen adsorption and enhances the stabilization of superoxide anion intermediate(·O_(2)~-).As a result,the as-synthesized photocatalysts exhibit a high H_(2)O_(2)production rate of 18μmol h^(-1)in pure water,which is three times that of pristine CPs,This work provides valuable insights into the design of organic polymer photocatalysts for various photocatalytic reactions.

关键词： Photocatalysis H_(2)O_(2) Exciton dissociation Conjugated polymers

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Elastic and Compressive Barium Aluminosilicate Nanofibrous Sponge for Thermal Insulation up to 1400 °C

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ACS Applied Nano Materials 2025年第19期8卷 9995-10003页

作者： Guo, Hangyuan Liu, Hualei Wei, Lingqiao Fang, Songchun Surmenev, Roman A. Liu, Yi-Tao Yu, Jianyong Ding, Bin State Key Laboratory of Advanced Fiber Materials College of Materials Science and Engineering Donghua University Shanghai201620 China School of Materials Science and Engineering Shanghai University of Engineering Science Shanghai201620 China Innovation Center for Textile Science and Technology College of Textiles Donghua University Shanghai201620 China Physical Materials Science and Composite Materials Center Research School of Chemistry & Applied Biomedical Sciences National Research Tomsk Polytechnic University Tomsk634050 Russia

Traditional ceramic materials are prone to crushing due to structural collapse at high temperatures. Current efforts are focused on developing flexible and elastic ceramic materials with high thermal stability to address practical needs in the field of high-temperature thermal insulation, but this remains a significant challenge. In this work, elastic and compressible barium aluminosilicate (BAS) nanofibrous sponges are fabricated through gelation electrospinning and calcination processes. The resulting BAS nanofibrous sponges demonstrate excellent elasticity and compressibility across a temperature range of −196 to 1400 °C and can withstand 1000 compression cycles without structural collapse. Furthermore, they exhibit low thermal conductivity (0.0239 W m-1 K-1), low bulk density (4.42 mg cm-3), and high working temperature. In this sense, our study highlights the great potential of BAS nanofibrous sponges as thermal protective materials in extreme operating environments. © 2025 American Chemical Society.

关键词： Thermal insulation

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Resilient ultrafine fiber sponges with thermal bridge structures for high-temperature traffic noise reduction

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Journal of Colloid and Interface science 2025年 693卷 137634页

作者： Li, Yanzhe Zong, Dingding Sun, Yaning Pang, Shuying Liao, Yalong Liu, Yong Ministry of Education Key Laboratory for Advanced Textile Composite Materials School of Textile Science and Engineering Tiangong University Tianjin300387 China Aerospace Institute of Advanced Material & Processing Technology Beijing100074 China

With the expansion of the transportation business, noise pollution has seriously affected human health and quality of life. Vehicles not only generate noise but also release a large amount of heat, existing traffic noise reduction materials have no thermal conductivity and poor low-frequency noise reduction. Herein, thermal bridge structured elastic ultrafine fiber sponges (TBFSs) were constructed in one step through simultaneous high-humidity assisted electrospinning and electrospraying. The thermal bridge structures endow fiber sponges with good thermal conductivity (close to 0.1 W m−1 K−1), increased by 350 % compared with common fiber sponges. More importantly, due to the complex pore channel and the vibration effect of the thermal bridge structures, the TBFSs achieve a high noise reduction coefficient of 0.58, which can reduce the high-temperature white noise by 16.5 dB at 100 °C. Besides, the synergistic effect of elastic polyurethane and heat crosslinking endows TBFSs with good mechanical properties, demonstrating negligible plastic deformation following 100 cycles of compressive loading. The successful development of thermal bridge structures fiber sponges provides a new solution for high-temperature safety noise reduction. © 2025 Elsevier Inc.

关键词： Noise abatement

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Crystallization-driven layer-by-layer amphiphilic block copolymer co-assembly with planar cargo molecules

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European Polymer Journal 2025年 234卷

作者： Zuo, Huiying Chen, Kaibin Zhai, Hong Dong, Jiao Quan, Daping Zhou, Jing Bai, Ying Key Laboratory for Polymeric Composite & Functional Materials of Ministry of Education Guangdong Engineering Technology Research Centre for Functional Biomaterials School of Materials Science and Engineering Sun Yat-sen University 132 Waihuan West Road HEMC Guangzhou510006 China Key Laboratory for Polymeric Composite & Functional Materials of Ministry of Education School of Chemistry Sun Yat-sen University 132 Waihuan West Road HEMC Guangzhou510006 China

Self-assembly of block copolymers (BCPs) in selective solvents often provides promising routes for fabrication of morphologically rich microcarriers. Herein, a sort of lamellar platelet-like structure has been obtained through co-assembly of amphiphilic diblock polycarbonates and certain species of small molecules. The diblock copolymer consisted of a hydrophobic segment with pendent cholesterol groups and a hydrophilic block decorated with branched polyethylenimine groups, synthesized by sequential ring-opening polymerization. Planar drug molecules (such as curcumin, coumarin, and steroids) served as the nuclei that facilitated crystallization of hydrophobic block of copolymer chains with pendent cholesterol groups. Such small-molecule-mediated crystallization can force the copolymer chains to be fully stretched and packed in an orderly fashion, inducing the co-assembly of the diblock polycarbonate and cargo molecules, rather than the BCP self-assembly driven by solvent-philic/solvent-phobic interaction. The thickness of the co-assembled platelet was highly dependent on the chain length (degree of polymerization) of the copolymer, as well as the layer numbers of the stacking lamellae. Furthermore, such platelet-like co-assemblies effectively reduced the dosage-dependent cytotoxicity of curcumin. Overall, we herein propose a novel mechanism for small molecule induced macromolecular assembly and well-controlled morphological modulation through layer-by-layer stacking, which holds great potential for drug delivery in versatile biomedical applications. © 2025 Elsevier Ltd

关键词： Ring opening polymerization

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Numerical and experimental analysis of hydraulic and thermal performance in additively manufactured topology-optimized heat sinks with different geometric features

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Applied Thermal Engineering 2025年 274卷

作者： Sun, Qidong Geng, Da Guo, Junzhe Zhou, Sheng Chen, Mingji Tao, Ran Institute of Advanced Structure Technology Beijing Institute of Technology Beijing100081 China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of Technology Beijing100081 China Ningbo Institute of Technology Beihang University Ningbo315100 China School of Aeronautic Science and Engineering Beihang University Beijing100191 China

With growing demand for efficient thermal management in high-power applications such as aerospace, energy systems, and microelectronics, this study explores a topology-optimized cooling channel design tailored for high heat flux conditions. The proposed design integrates numerical simulations and experimental validation to enhance thermal–hydraulic performance. The optimized 2 mm channel demonstrated a 55 % enhancement in both heat transfer coefficient and Nusselt number, a 60 % higher performance evaluation coefficient, and a lower thermal resistance of 0.0073 ℃/W. Experimental characterization of laser powder bed fusion fabricated AlSi10Mg alloy revealed anisotropic thermal conductivity governed by grain size variations, which was incorporated into simulations to improve predictive accuracy. Computed tomography and scanning electron microscopy analyses identified surface roughness as a key factor influencing pressure drop, with deviations attributed to additive manufacturing constraints. Experimental temperature measurements closely aligned with numerical predictions, showing that the optimized 2 mm channel reduced operating temperature by 9.6 % compared to the reference design. These findings highlight the balance between heat transfer efficiency and flow resistance, providing valuable insights into optimizing cooling channel designs for energy-efficient thermal management in high-performance electronics, renewable energy systems, and aerospace applications. © 2025 Elsevier Ltd

关键词： Electronic cooling

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Stacking effects on magnetic, vibrational, and optical properties of CrSBr bilayers

arXiv

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arXiv 2025年

作者： Li, Huicong Yang, Yali Xia, Zhonghao Wang, Yateng Wei, Jiacheng He, Jiangang Wang, Rongming Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science The State Key Laboratory for Advanced Metals and Materials School of Mathematics and Physics University of Science and Technology Beijing Beijing100083 China

Layer stacking presents a promising avenue for manipulating the physical properties of two-dimensional materials. The van der Waals layered semiconductor CrSBr, which exhibits A-type antiferromagnetism and a relatively high Néel temperature, has been successfully exfoliated into atomically thin sheets. In this study, we investigate the structural, lattice dynamical, electronic, magnetic, and optical properties of four distinct stacking structures of CrSBr bilayers using first-principles calculations and Monte Carlo simulations. Our findings show that though the most energetically favorable bilayer structure retains the stacking pattern of the bulk counterpart, three other high-symmetry stacking structures can be achieved by sliding one of the layers along three distinct directions, with energy costs comparable to that observed in MoS2 bilayer. All these four bilayers exhibit semiconductor behavior with A-type antiferromagnetic ordering, similar to the bulk material, and demonstrate closely aligned Néel temperatures. Moreover, these bilayers exhibit relatively low lattice thermal conductivities, pronounced anisotropy, and a strong dependence on stacking patterns. This behavior is attributed to significant phonon-phonon scattering arising from avoided crossings between acoustic and optical phonons, as well as the presence of flat optical phonon bands in the low-frequency region. While the electronic structures and optical properties of these bilayers show weak dependence on the stacking pattern for antiferromagnetic ordering, they undergo significant changes for ferromagnetic ordering, influencing the band gap, valence and conduction band splitting, and effective mass. Furthermore, we found that antiferromagnetic ordering can transition to ferromagnetic under intense visible light illumination. Thus, the integration of layer stacking and visible light illumination offers an effective means to control the heat transfer, magnetic, and optical properties of CrSBr bilayer

关键词： Layered semiconductors

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Molecular simulations in elucidating the unique behaviors of polymers induced by chain connectivity: A personal review

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Polymer 2025年 332卷

作者： Xu, Tingyu Peng, Fan Cao, Renkuan Sun, Hao Liu, Ziwei Zhang, Yunhan Li, Liangbin National Synchrotron Radiation Lab Anhui Provincial Engineering Laboratory of Advanced Functional Polymer Film CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China Hefei230026 China

Polymer materials possess unique chain connectivity structure, which endows them with distinctive features in terms of structure, thermodynamics, and dynamics. Traditional polymer physics focuses on how this unique chain connectivity governs the microscopic dynamics and interactions in polymer systems, differentiating their properties from those of small-molecule systems. This review revisits our several efforts made using molecular simulations to explore specific, unresolved issues in polymer systems, offering readers a personal perspective on the significant role of molecular simulation methods in advancing polymer physics. The review discusses the effects of chain connectivity from the perspectives of entanglement constraints, chain segment stretching, and orientation, introducing phenomena including chain orientation tumbling and shear banding in nonlinear polymer rheology, crystallization in biaxially stretched and entanglement-modified polymer melts, and bond orientation-determined stress in glassy polymers. © 2025 Elsevier Ltd

关键词： Molecular modeling

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Integration of Electrical Properties and Polarization Loss Modulation on Atomic Fe–N‑RGO for Boosting Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 517-532页

作者： Kaili Zhang Yuefeng Yan Zhen Wang Guansheng Ma Dechang Jia Xiaoxiao Huang Yu Zhou State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001People’s Republic of China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China MIIT Key Laboratory of Advanced Structural‑Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001People’s Republic of China

Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)*** on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible ***,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted *** composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA *** results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural ***,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy *** study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.

关键词： Electromagnetic wave absorption Fe-N-RGO Dipole polarization Conduction loss Impedance matching

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