查找使用阿拉丁产品的科研文献

In situ TEM observation of liquid flow induced dense phase formation and anisotropic nanocrystal growth

Peng Xue,Xiao-Tian Jiang,Mi Qu,Tiqing Zhao,You-Hong Jiang,Yifan Ying,Yong Luo,Dan Wang,Guang-Wen Chu,Jian-Feng Chen,Shi-Gang Sun,Hong-Gang Liao

The nucleation and growth of crystals from solutions are fundamental to materials synthesis and its applications. The mass transfer at micro/nano region in solution will greatly influence the crystal growth process, however, to our knowledge, there is rarely research at this scale due to the technique limit. By using in situ liquid cell transmission electron microscopy (TEM), we observed the crystal growth at flow condition with high resolution in real time. Interestingly, we found a flow induced formation of the solute rich dense liquid phase near surface at ultra-low precursor concentration, which then transformed to nanocrystals. The dendritic crystal growth was accelerated by the dense phase droplet merging and the anisotropic crystal growth was controlled by dense phase shape evolution. Our study deepens the understanding of crystal growth mechanisms, which is crucial to determine reaction dynamics and design hierarchical nanomaterials.

Unveiling the Thermal Transitions of Silver Nanowires via In Situ TEM: Insights into Energy Transfer and Interfacial Stability

Jitao Shang,Shasha Wei,Yuan Ai,Yayun Zheng,Baoshuo Yang,Du Wang,Yan Zhao

Silver nanowires (Ag NWs) possess remarkable attributes, such as high surface area, excellent conductivity, optical properties, and strong anisotropy, rendering them highly promising for diverse applications in flexible electronics, transparent electrodes, and other fields. However, a comprehensive understanding of their thermodynamic behavior remains elusive. Given the temperature sensitivity of Ag NWs, it becomes imperative to unravel their degradation mechanisms, ensuring their reliability in practical usage. In this study, we conducted an extensive analysis of well-defined polycrystalline Ag NWs, employing in situ TEM to investigate their thermal transitions. Our research revealed that the different forms of energy transfer and interfacial stability resulted in different degrees of transformation of Ag NWs under different thermal conditions. We recorded these transformations in complete and detailed videos. These outcomes provide a solid foundation for attaining a comprehensive understanding of the thermal properties of Ag NWs, propelling their utilization in scientific research and industrial applications.

Uptake and Translocation of Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) by Wetland Plants: Tissue- and Cell-Level Distribution Visualization with Desorption Electrospray Ionization Mass Spectrometry (DESI-MS) and Transmission Electron Microscopy Equipped with Energy-Dispersive Spectroscopy (TEM-EDS)

Tuan-Tuan Wang,Guang-Guo Ying,Wen-Jun Shi,Jian-Liang Zhao,You-Sheng Liu,Jun Chen,Dong-Dong Ma,Qian Xiong

Perfluoroalkyl substances (PFASs) are persistent chemicals in the environment. So far, little is known about their uptake potential in wetland plants. Here, we investigated the uptake and translocation of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in eight common wetland plants, namely, Canna indica (Ci), Thalia dealbata (Td), Cyperus alternifolius (Ca), Phragmites australis (Pa), Arundo donax (Ad), Pontederia cordata (Pc), Cyperus papyrus (Cp), and Alisma orientale (Ao) by hydroponic experiments and visualized their tissue- and cell-level distribution with desorption electrospray ionization mass spectrometry (DESI-MS) and transmission electron microscopy equipped with energy-dispersive spectroscopy (TEM-EDS). The results showed that the PFASs accumulated in plants accounted for 1.67–16.7% of the total mass spiked into the hydroponic systems, and PFOS accumulated largely in roots (48.8–95.8%), while PFOA was stored mostly in the aboveground part (29.3–77.4%). DESI-MS and TEM-EDS analysis showed that PFASs in Ci, Td, Pa, and Ca were transported from the hydroponic solution to the root cortex via both apoplastic (e.g., across cell walls and/or intercellular spaces) and symplastic routes (e.g., across plasma membranes or via plasmodesmata) and further to the vascular bundle via symplastic route in Td and Pa and via both routes in Ci and Ca. These two chemicals were transported from roots to stems mainly through the cortex in Td and through both the cortex and vascular bundles in Ci and Ca.

Cryo-ultramicrotomy enables TEM characterization of global lithium/polymer interfaces

Xuedong Zhang,Ziang Guo,Xin Li,Qiunan Liu,Huan Hu,Fangyuan Li,Qiao Huang,Liqiang Zhang,Yongfu Tang,Jianyu Huang

Lithium electrochemistry dictates the safety and cycling durability of lithium metal batteries. Although there have been numerous spectroscopy studies of lithium in liquid electrolyte batteries, electron microscopy studies of lithium in solid state batteries are scarce due to the technical difficulty of sample fabrication. In this work, we introduce an innovative specimen preparation methodology dubbed cryo-ultramicrotomy to fabricate large-scale cryo-TEM specimens that permit direct visualization of global anode/electrolyte interfaces and lithium within the polymer electrolyte from the nanometer to millimeter scale. By combining electron energy loss spectroscopy and multivariate least squares fitting, we map the lithium/PEO interface and the deposited lithium clusters, revealing a novel tri-layer SEI|Li|SEI structure on the lithium anode surface, indicating that electrons can tunnel through the SEI layer. The deposited lithium features either isolated or interconnected clusters that are different from the lithium dendrites in liquid electrolytes. The lithium clusters comprise Li0 and LiH cores surrounded by inorganic components such as Li2O and LiOH but with little LiF, which are further enwrapped by the organic components. Based on this understanding, tetrabutylammonium fluoride was introduced into the electrolyte to tailor the SEI and PEO structures to significantly improve the electrochemical performance of lithium metal batteries.

Atomic dynamics of electrified solid–liquid interfaces in liquid-cell TEM

Zhang Qiubo,Song Zhigang,Sun Xianhu,Liu Yang,Wan Jiawei,Betzler Sophia B.,Zheng Qi,Shangguan Junyi,Bustillo Karen C.,Ercius Peter,Narang Prineha,Huang Yu,Zheng Haimei

Electrified solid–liquid interfaces (ESLIs) play a key role in various electrochemical processes relevant to energy 1 , 2 , 3 , 4 , 5 , biology 6 and geochemistry 7 . The electron and mass transport at the electrified interfaces may result in structural modifications that markedly influence the reaction pathways. For example, electrocatalyst surface restructuring during reactions can substantially affect the catalysis mechanisms and reaction products 1 , 2 , 3 . Despite its importance, direct probing the atomic dynamics of solid–liquid interfaces under electric biasing is challenging owing to the nature of being buried in liquid electrolytes and the limited spatial resolution of current techniques for in situ imaging through liquids. Here, with our development of advanced polymer electrochemical liquid cells for transmission electron microscopy (TEM), we are able to directly monitor the atomic dynamics of ESLIs during copper (Cu)-catalysed CO 2 electroreduction reactions (CO 2 ERs). Our observation reveals a fluctuating liquid-like amorphous interphase. It undergoes reversible crystalline–amorphous structural transformations and flows along the electrified Cu surface, thus mediating the crystalline Cu surface restructuring and mass loss through the interphase layer. The combination of real-time observation and theoretical calculations unveils an amorphization-mediated restructuring mechanism resulting from charge-activated surface reactions with the electrolyte. Our results open many opportunities to explore the atomic dynamics and its impact in broad systems involving ESLIs by taking advantage of the in situ imaging capability.

TEM Analysis of Orientational Domain Evolution Triggered by Structural Phase Transition in Bi0.25Ca0.75MnO3 Ceramics

The structural phase transition and associated orientational domain configurations in perovskite-type BixCa1−xMnO3ceramics were investigated in this work. A series of BixCa1−xMnO3solid solutions withx= 0.05, 0.25, 0.33 were synthesized, and Bi0.25Ca0.75MnO3with moderate orthorhombic lattice distortion was selected as the representative sample for systematic TEM characterization. Upon cooling from high temperature, the material undergoes a symmetry-lowering transition from the cubic phase with Pm̅3m space group to the orthorhombic phase with Pnma space group. Selected-area electron diffraction (SAED) and bright-field TEM observations reveal the formation of multiple orientational domains, including both 90° and 120° configurations, within individual grains. High-resolution TEM (HRTEM) further confirms the coexistence of three distinct domain orientations at the atomic scale, with well-defined lattice fringes and domain boundaries. The reciprocal-space orientational relationships derived from SAED patterns demonstrate that these domains originate from the symmetry breaking of the parent cubic lattice during the phase transition. These findings provide direct crystallographic insight into the domain structures of BCMO, and such microstructural features are essential for revealing the structural stability and intrinsic functional behaviors of BCMO manganites.

Unraveling the Conversion Evolution on Solid-State Na–SeS2 Battery via In Situ TEM

Ziqi Zhang,Zaifa Wang,Long Zhang,Di Liu,Chuang Yu,Xinlin Yan,Jia Xie,Jianyu Huang

All-solid-state (ASS) Na–S batteries are promising for a large-scale energy-storage system owing to numerous merits. However, the high conversion reaction barrier impedes their practical application. In this work, the basic mechanism on how Se catalyzes the conversion reaction in the Na–S batteries is unraveled. The sodiation/desodiation of Na–SeS 2 nanobatteries are systematically evaluated via in situ transmission electron microscopy (in situ TEM) with a microheating device. The real-time analyses reveal an amorphous Na–Se x S y intermediate phase appears during the direct conversion from SeS 2 to Na 2 S, and a reverse reaction succeeds at 100 °C with a prior formation of Se. The absence of polysulfides and a much lower desodiation temperature in contrast to Na–S nanobatteries demonstrate that the Se incorporation significantly lowers the conversion reaction barrier. According to these findings, the ASS SeS 2 batteries using a Na 3 SbS 4 solid electrolyte (SE) are assembled using various SE:C ratios in the composite cathodes to investigate the effect of the ion and electron transport on the electrochemical properties, including the effective transport properties, MacMullin number, and the tortuosity factor. The obtained results in turn confirm the findings from the in situ TEM. These findings are applicable to optimize other S-based active materials and improve their utilization.

Enhancing the Electron Radiation Resistance of Macromolecules in Cryo-TEM Imaging Using Sodium Ascorbate

Pilan Zhang,Xiaoduo Dong,Haiqin Du,Shiwen Cui,Jingyi Liu,Yixiang He,Wenjie Ren,Hui Wang,Ying Zhang,Yifei Xu

Electron radiation damage hinders the high-resolution cryogenic transmission electron microscopy (cryo-TEM) imaging of macromolecules. In this work, sodium ascorbate (SA) was used to eliminate reactive oxygen species generated during electron radiation, thereby enhancing the electron radiation resistance of macromolecular samples in cryo-TEM experiments. The effectiveness of SA on protecting sample morphology and structure was investigated for representative types of macromolecular samples, including collagen, cellulose, liposome, and apoferritin, and compared with other radical scavengers. Our findings revealed that SA provided the most effective protection for collagen, increasing its dose limit by more than 40%. Similar effects were observed for cellulose and apoferritin. Importantly, the addition of SA does not change the three-dimensional structure of apoferritin, as confirmed by a 2.2 Å resolution single particle analysis, further indicating the practicality of the method.

Automated Particle Size Analysis of Supported Nanoparticle TEM Images Using a Pre-Trained SAM Model

Xiukun Zhong,Guohong Liang,Lingbei Meng,Wei Xi,Lin Gu,Nana Tian,Yong Zhai,Yutong He,Yuqiong Huang,Fengmin Jin,Hong Gao

This study addresses the challenges associated with transmission electron microscopy (TEM) image analysis of supported nanoparticles, including low signal-to-noise ratio, poor contrast, and interference from complex substrate backgrounds. This study proposes an automated segmentation and particle size analysis method based on a large-scale deep learning model, namely segment anything model (SAM). Using Ru/TiO2and related materials as representative systems, the pretrained SAM is employed for zero-shot segmentation of nanoparticles, which is further integrated with a custom image processing pipeline, including optical character recognition (OCR) module, morphological optimization, and connected component analysis to achieve high-precision particle size quantification. Experimental results demonstrate that the method retains robust performance under challenging imaging conditions, with a size estimation error between 3% and 5% and a per-image processing time under 1 min, significantly outperforming traditional manual annotation and threshold-based segmentation approaches. This framework provides an efficient and reliable analytical tool for morphological characterization and structure–performance correlation studies in supported nanocatalysts.

In Situ TEM Observation of Phase Transformation Nucleation at the Near-Surface of Synthetic Aragonite

Lehua Wang,Xinshuang Guo,Yuanyuan Zhang,Chaochao Fu,Xingyuan San

Electron beam irradiation is well known to induce damage to materials during transmission electron microscope (TEM) characterization, especially for insulating materials. Phase transformation is an important damage phenomenon caused by beam irradiation. Here, we employed in situ TEM combined with electron-energy loss spectroscopy (EELS) to dynamically track the phase transformation of synthetic aragonite. The evolution process and underlying mechanism of the phase transformation in aragonite are systematically discussed. This work reveals that the near-surface region of aragonite undergoes a phase transformation induced by electron beam irradiation, prior to the bulk of aragonite. It provides more possibilities for searching the multiple near-surface properties of materials. Highlights The TEM and EELS are used to track the near-surface phase transformation in synthetic aragonite. The near-surface is easily changed compared with the bulk part of aragonite under electron beam irradiation. The mechanism of beam damage in the near-surface region is the result of the combined effect of knock-on displacement and radiolysis, whereas the bulk region undergoes phase transformation due to radiolysis. The phenomenon that the bulk is more severely damaged at the periphery of electron beam is attributed to the DIEF mechanism.

Atomic-Scale Cryo-TEM Studies of the Electrochemistry of Redox Mediator in Li–O2 Batteries

Zhiying Gao,Jingming Yao,Jitong Yan,Jun Sun,Congcong Du,Qiushi Dai,Yong Su,Jun Zhao,Jingzhao Chen,Xiaomei Li,Hui Li,Pan Zhang,Jun Ma,Hailong Qiu,Liqiang Zhang,Yongfu Tang,Jianyu Huang

Rechargeable aprotic lithium (Li)-oxygen battery (LOB) is a potential next-generation energy storage technology because of its high theoretical specific energy. However, the role of redox mediator on the oxide electrochemistry remains unclear. This is partly due to the intrinsic complexity of the battery chemistry and the lack of in-depth studies of oxygen electrodes at the atomic level by reliable techniques. Herein, cryo-transmission electron microscopy (cryo-TEM) is used to study how the redox mediator LiI affects the oxygen electrochemistry in LOBs. It is revealed that with or without LiI in the electrolyte, the discharge products are plate-like LiOH or toroidal Li 2 O 2 , respectively. The I 2 assists the decomposition of LiOH via the formation of LiIO 3 in the charge process. In addition, a LiI protective layer is formed on the Li anode surface by the shuttle of I 3 − , which inhibits the parasitic Li/electrolyte reaction and improves the cycle performance of the LOBs. The LOBs returned to 2e − oxygen reduction reaction (ORR) to produce Li 2 O 2 after the LiI in the electrolyte is consumed. This work provides new insight on the role of redox mediator on the complex electrochemistry in LOBs which may aid the design LOBs for practical applications.

Re-recognizing micro locations of nanoscale zero-valent iron in biochar using C-TEM technique

Yang Kun,Xu Jialu,Zhang Ming,Lin Daohui

Biochar supported nanoscale zero-valent iron (NZVI/BC), prepared commonly by liquid reduction using sodium borohydride (NaBH 4 ), exhibits better reduction performance for contaminants than bare NZVI. The better reducing ability was attributed to attachment of nanoscale zero-valent iron (NZVI) on biochar (BC) surface or into the interior pores of BC particles due to observations by scanning electron microscopy (SEM) and plan transmission electron microscopy (P-TEM) techniques in previous studies. In this study, cross-sectional TEM (C-TEM) technique was employed firstly to explore location of NZVI in NZVI/BC. It was observed that NZVI is isolated from BC particles, but not located on the surface or in the interior pores of BC particles. This observation was also supported by negligible adsorption and precipitation of Fe 2+ /Fe 3+ and iron hydroxides on BC surface or into interior pores of BC particles respectively. Precipitation of Fe 2+ and Fe 3+ , rather than adsorption, is responsible for the removal of Fe 2+ and Fe 3+ by BC. Moreover, precipitates of iron hydroxides cannot be reduced to NZVI by NaBH 4 . In addition to SEM or P-TEM, therefore, C-TEM is a potential technique to characterize the interior morphology of NZVI/BC for better understanding the improved reduction performance of contaminants by NZVI/BC than bare NZVI.