1
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Merkens S, Tollan C, De Salvo G, Bejtka K, Fontana M, Chiodoni A, Kruse J, Iriarte-Alonso MA, Grzelczak M, Seifert A, Chuvilin A. Toward sub-second solution exchange dynamics in flow reactors for liquid-phase transmission electron microscopy. Nat Commun 2024; 15:2522. [PMID: 38514605 PMCID: PMC10957994 DOI: 10.1038/s41467-024-46842-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 03/11/2024] [Indexed: 03/23/2024] Open
Abstract
Liquid-phase transmission electron microscopy is a burgeoning experimental technique for monitoring nanoscale dynamics in a liquid environment, increasingly employing microfluidic reactors to control the composition of the sample solution. Current challenges comprise fast mass transport dynamics inside the central nanochannel of the liquid cell, typically flow cells, and reliable fixation of the specimen in the limited imaging area. In this work, we present a liquid cell concept - the diffusion cell - that satisfies these seemingly contradictory requirements by providing additional on-chip bypasses to allow high convective transport around the nanochannel in which diffusive transport predominates. Diffusion cell prototypes are developed using numerical mass transport models and fabricated on the basis of existing two-chip setups. Important hydrodynamic parameters, i.e., the total flow resistance, the flow velocity in the imaging area, and the time constants of mixing, are improved by 2-3 orders of magnitude compared to existing setups. The solution replacement dynamics achieved within seconds already match the mixing timescales of many ex-situ scenarios, and further improvements are possible. Diffusion cells can be easily integrated into existing liquid-phase transmission electron microscopy workflows, provide correlation of results with ex-situ experiments, and can create additional research directions addressing fast nanoscale processes.
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Affiliation(s)
- Stefan Merkens
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018, Donostia-San Sebastián, Spain.
- Department of Physics, Euskal Herriko Unibertsitatea (UPV/EHU), 20018, Donostia-San Sebastián, Spain.
| | - Christopher Tollan
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018, Donostia-San Sebastián, Spain
| | - Giuseppe De Salvo
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018, Donostia-San Sebastián, Spain
- Department of Physics, Euskal Herriko Unibertsitatea (UPV/EHU), 20018, Donostia-San Sebastián, Spain
| | - Katarzyna Bejtka
- Center for Sustainable Future Technologies@Polito, Istituto Italiano di Tecnologia (IIT), Via Livorno, 60, 10144, Torino, TO, Italy
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, corso Duca degli Abruzzi 24, 10129, Torino, Italy
| | - Marco Fontana
- Center for Sustainable Future Technologies@Polito, Istituto Italiano di Tecnologia (IIT), Via Livorno, 60, 10144, Torino, TO, Italy
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, corso Duca degli Abruzzi 24, 10129, Torino, Italy
| | - Angelica Chiodoni
- Center for Sustainable Future Technologies@Polito, Istituto Italiano di Tecnologia (IIT), Via Livorno, 60, 10144, Torino, TO, Italy
| | - Joscha Kruse
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018, Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018, Donostia-San Sebastián, Spain
| | - Maiara Aime Iriarte-Alonso
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018, Donostia-San Sebastián, Spain
- TECNIPESA IDENTIFICACION SL, Parque Empresarial Zuatzu, Edificio Donosti 1-3, 20018, Donostia-San Sebastián, Spain
| | - Marek Grzelczak
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, 20018, Donostia-San Sebastián, Spain
- Centro de Física de Materiales CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018, Donostia-San Sebastián, Spain
| | - Andreas Seifert
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009, Bilbao, Spain
| | - Andrey Chuvilin
- CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018, Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009, Bilbao, Spain
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2
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Gindele MB, Vinod-Kumar S, Rochau J, Boemke D, Groß E, Redrouthu VS, Gebauer D, Mathies G. Colloidal pathways of amorphous calcium carbonate formation lead to distinct water environments and conductivity. Nat Commun 2024; 15:80. [PMID: 38167336 PMCID: PMC10761707 DOI: 10.1038/s41467-023-44381-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
CaCO3 is the most abundant biomineral and a major constituent of incrustations arising from water hardness. Polycarboxylates play key roles in controlling mineralization. Herein, we present an analytical and spectroscopic study of polycarboxylate-stabilized amorphous CaCO3 (ACC) and its formation via a dense liquid precursor phase (DLP). Polycarboxylates facilitate pronounced, kinetic bicarbonate entrapment in the DLP. Since bicarbonate is destabilized in the solid state, DLP dehydration towards solid ACC necessitates the formation of locally calcium deficient sites, thereby inhibiting nucleation. Magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy of poly-aspartate-stabilized ACC reveals the presence of two distinct environments. The first contains immobile calcium and carbonate ions and structural water molecules, undergoing restricted, anisotropic motion. In the second environment, water molecules undergo slow, but isotropic motion. Indeed, conductive atomic force microscopy (C-AFM) reveals that ACC conducts electrical current, strongly suggesting that the mobile environment pervades the bulk of ACC, with dissolved hydroxide ions constituting the charge carriers. We propose that the distinct environments arise from colloidally stabilized interfaces of DLP nanodroplets, consistent with the pre-nucleation cluster (PNC) pathway.
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Affiliation(s)
- Maxim B Gindele
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | - Sanjay Vinod-Kumar
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78464, Konstanz, Germany
| | - Johannes Rochau
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | - Daniel Boemke
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | - Eduard Groß
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | | | - Denis Gebauer
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany.
| | - Guinevere Mathies
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78464, Konstanz, Germany.
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3
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Chee SW, Lunkenbein T, Schlögl R, Roldán Cuenya B. Operando Electron Microscopy of Catalysts: The Missing Cornerstone in Heterogeneous Catalysis Research? Chem Rev 2023; 123:13374-13418. [PMID: 37967448 PMCID: PMC10722467 DOI: 10.1021/acs.chemrev.3c00352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 10/14/2023] [Accepted: 10/20/2023] [Indexed: 11/17/2023]
Abstract
Heterogeneous catalysis in thermal gas-phase and electrochemical liquid-phase chemical conversion plays an important role in our modern energy landscape. However, many of the structural features that drive efficient chemical energy conversion are still unknown. These features are, in general, highly distinct on the local scale and lack translational symmetry, and thus, they are difficult to capture without the required spatial and temporal resolution. Correlating these structures to their function will, conversely, allow us to disentangle irrelevant and relevant features, explore the entanglement of different local structures, and provide us with the necessary understanding to tailor novel catalyst systems with improved productivity. This critical review provides a summary of the still immature field of operando electron microscopy for thermal gas-phase and electrochemical liquid-phase reactions. It focuses on the complexity of investigating catalytic reactions and catalysts, progress in the field, and analysis. The forthcoming advances are discussed in view of correlative techniques, artificial intelligence in analysis, and novel reactor designs.
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Affiliation(s)
- See Wee Chee
- Department
of Interface Science, Fritz-Haber Institute
of the Max-Planck Society, 14195 Berlin, Germany
| | - Thomas Lunkenbein
- Department
of Inorganic Chemistry, Fritz-Haber Institute
of the Max-Planck Society, 14195 Berlin, Germany
| | - Robert Schlögl
- Department
of Interface Science, Fritz-Haber Institute
of the Max-Planck Society, 14195 Berlin, Germany
| | - Beatriz Roldán Cuenya
- Department
of Interface Science, Fritz-Haber Institute
of the Max-Planck Society, 14195 Berlin, Germany
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4
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Couasnon T, Fritsch B, Jank MPM, Blukis R, Hutzler A, Benning LG. Goethite Mineral Dissolution to Probe the Chemistry of Radiolytic Water in Liquid-Phase Transmission Electron Microscopy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301904. [PMID: 37439408 PMCID: PMC10477898 DOI: 10.1002/advs.202301904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/20/2023] [Indexed: 07/14/2023]
Abstract
Liquid-Phase Transmission Electron Microscopy (LP-TEM) enables in situ observations of the dynamic behavior of materials in liquids at high spatial and temporal resolution. During LP-TEM, incident electrons decompose water molecules into highly reactive species. Consequently, the chemistry of the irradiated aqueous solution is strongly altered, impacting the reactions to be observed. However, the short lifetime of these reactive species prevent their direct study. Here, the morphological changes of goethite during its dissolution are used as a marker system to evaluate the influence of radiation on the changes in solution chemistry. At low electron flux density, the morphological changes are equivalent to those observed under bulk acidic conditions, but the rate of dissolution is higher. On the contrary, at higher electron fluxes, the morphological evolution does not correspond to a unique acidic dissolution process. Combined with kinetic simulations of the steady state concentrations of generated reactive species in the aqueous medium, the results provide a unique insight into the redox and acidity interplay during radiation induced chemical changes in LP-TEM. The results not only reveal beam-induced radiation chemistry via a nanoparticle indicator, but also open up new perspectives in the study of the dissolution process in industrial or natural settings.
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Affiliation(s)
- Thaïs Couasnon
- GFZ German Research Center for GeosciencesTelegrafenberg14473PotsdamGermany
| | - Birk Fritsch
- Department of Electrical, Electronic, and Communication EngineeringElectron DevicesFriedrich‐Alexander‐Universität Erlangen‐Nürnberg91058ErlangenGermany
- Department of Materials Science and EngineeringInstitute of Micro‐ and Nanostructure Research (IMN) and Center for Nanoanalysis and Electron Microscopy (CENEM)Friedrich‐Alexander‐Universität Erlangen‐Nürnberg91058ErlangenGermany
- Forschungszentrum Jülich GmbHHelmholtz Institute Erlangen‐Nürnberg for Renewable Energy (IEK‐11)91058ErlangenGermany
| | - Michael P. M. Jank
- Fraunhofer Institute for Integrated Systems and Device Technology IISBSchottkystr. 1091058ErlangenGermany
| | - Roberts Blukis
- GFZ German Research Center for GeosciencesTelegrafenberg14473PotsdamGermany
- Leibniz‐Institut für KristallzüchtungMax‐Born Str. 212489BerlinGermany
| | - Andreas Hutzler
- Department of Electrical, Electronic, and Communication EngineeringElectron DevicesFriedrich‐Alexander‐Universität Erlangen‐Nürnberg91058ErlangenGermany
- Forschungszentrum Jülich GmbHHelmholtz Institute Erlangen‐Nürnberg for Renewable Energy (IEK‐11)91058ErlangenGermany
| | - Liane G. Benning
- GFZ German Research Center for GeosciencesTelegrafenberg14473PotsdamGermany
- Department of Earth SciencesFreie Universität Berlin12249BerlinGermany
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5
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Ma H, Kang S, Lee S, Park G, Bae Y, Park G, Kim J, Li S, Baek H, Kim H, Yu JS, Lee H, Park J, Yang J. Moisture-Induced Degradation of Quantum-Sized Semiconductor Nanocrystals through Amorphous Intermediates. ACS NANO 2023. [PMID: 37399231 DOI: 10.1021/acsnano.3c03103] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Elucidating the water-induced degradation mechanism of quantum-sized semiconductor nanocrystals is an important prerequisite for their practical application because they are vulnerable to moisture compared to their bulk counterparts. In-situ liquid-phase transmission electron microscopy is a desired method for studying nanocrystal degradation, and it has recently gained technical advancement. Herein, the moisture-induced degradation of semiconductor nanocrystals is investigated using graphene double-liquid-layer cells that can control the initiation of reactions. Crystalline and noncrystalline domains of quantum-sized CdS nanorods are clearly distinguished during their decomposition with atomic-scale imaging capability of the developed liquid cells. The results reveal that the decomposition process is mediated by the involvement of the amorphous-phase formation, which is different from conventional nanocrystal etching. The reaction can proceed without the electron beam, suggesting that the amorphous-phase-mediated decomposition is induced by water. Our study discloses unexplored aspects of moisture-induced deformation pathways of semiconductor nanocrystals, involving amorphous intermediates.
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Affiliation(s)
- Hyeonjong Ma
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Sungsu Kang
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Seunghan Lee
- Department of Physics, Konkuk University, Seoul 05029, Korea
| | - Gisang Park
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Yuna Bae
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Gyuri Park
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Jihoon Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Shi Li
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Hayeon Baek
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyeongseung Kim
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Jong-Sung Yu
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
- Energy Science and Engineering Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Hoonkyung Lee
- Department of Physics, Konkuk University, Seoul 05029, Korea
| | - Jungwon Park
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- School of Chemical and Biological Engineering, and Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
- Institute of Engineering Research, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
- Advanced Institute of Convergence Technology, Seoul National University, Suwon-si, Gyeonggi-do 16229, Republic of Korea
| | - Jiwoong Yang
- Department of Energy Science and Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
- Energy Science and Engineering Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
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6
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Merkens S, De Salvo G, Kruse J, Modin E, Tollan C, Grzelczak M, Chuvilin A. Quantification of reagent mixing in liquid flow cells for Liquid Phase-TEM. Ultramicroscopy 2023; 245:113654. [PMID: 36470094 DOI: 10.1016/j.ultramic.2022.113654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 11/11/2022] [Accepted: 11/20/2022] [Indexed: 11/27/2022]
Abstract
Liquid-Phase Transmission Electron Microscopy (LP-TEM) offers the opportunity to study nanoscale dynamics of phenomena related to materials and life science in a native liquid environment and in real time. Until now, the opportunity to control/induce such dynamics by changing the chemical environment in the liquid flow cell (LFC) has rarely been exploited due to an incomplete understanding of hydrodynamic properties of LP-TEM flow systems. This manuscript introduces a method for hydrodynamic characterization of LP-TEM flow systems based on monitoring transmitted intensity while flowing a strongly electron scattering contrast agent solution. Key characteristic temporal indicators of solution replacement for various channel geometries were experimentally measured. A numerical physical model of solute transport based on realistic flow channel geometries was successfully implemented and validated against experiments. The model confirmed the impact of flow channel geometry on the importance of convective and diffusive solute transport, deduced by experiment, and could further extend understanding of hydrodynamics in LP-TEM flow systems. We emphasize that our approach can be applied to hydrodynamic characterization of any customized LP-TEM flow system. We foresee the implemented predictive model driving the future design of application-specific LP-TEM flow systems and, when combined with existing chemical reaction models, to a flourishing of the planning and interpretation of experimental observations.
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Affiliation(s)
- Stefan Merkens
- Electron Microscopy Laboratory, CIC nanoGUNE BRTA, Tolosa Hiribidea 76, Donostia, San Sebastián 20018, Spain; Department of Physics, Euskal Herriko Unibertsitatea (UPV/EHU), Donostia, San Sebastián 20018, Spain.
| | - Giuseppe De Salvo
- Electron Microscopy Laboratory, CIC nanoGUNE BRTA, Tolosa Hiribidea 76, Donostia, San Sebastián 20018, Spain; Department of Physics, Euskal Herriko Unibertsitatea (UPV/EHU), Donostia, San Sebastián 20018, Spain
| | - Joscha Kruse
- Electron Microscopy Laboratory, CIC nanoGUNE BRTA, Tolosa Hiribidea 76, Donostia, San Sebastián 20018, Spain; Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia, San Sebastián 20018, Spain
| | - Evgenii Modin
- Electron Microscopy Laboratory, CIC nanoGUNE BRTA, Tolosa Hiribidea 76, Donostia, San Sebastián 20018, Spain
| | - Christopher Tollan
- Electron Microscopy Laboratory, CIC nanoGUNE BRTA, Tolosa Hiribidea 76, Donostia, San Sebastián 20018, Spain
| | - Marek Grzelczak
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, Donostia, San Sebastián 20018, Spain; Centro de Física de Materiales CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, Donostia, San Sebastián 20018, Spain
| | - Andrey Chuvilin
- Electron Microscopy Laboratory, CIC nanoGUNE BRTA, Tolosa Hiribidea 76, Donostia, San Sebastián 20018, Spain; Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
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7
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Wang H, Xu Z, Mao S, Granick S. Experimental Guidelines to Image Transient Single-Molecule Events Using Graphene Liquid Cell Electron Microscopy. ACS NANO 2022; 16:18526-18537. [PMID: 36256532 DOI: 10.1021/acsnano.2c06766] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In quest of the holy grail to "see" how individual molecules interact in liquid environments, single-molecule imaging methods now include liquid-phase electron microscopy, whose resolution can be nanometers in space and several frames per second in time using an ordinary electron microscope that is routinely available to many researchers. However, with the current state of the art, protocols that sound similar to those described in the literature lead to outcomes that can differ. The key challenge is to achieve sample contrast under a safe electron dose within a frame rate adequate to capture the molecular process. Here, we present such examples from different systems─synthetic polymer, lipid assembly, DNA-enzyme─in which we have done this using graphene liquid cells. We describe detailed experimental procedures and share empirical experience for conducting successful experiments, starting from fabrication of a graphene liquid cell, to identification of high-quality liquid pockets from desirable shapes and sizes, to effective searching for target sample pockets under electron microscopy, and to discrimination of sample molecules and molecular processes of interest. These experimental tips can assist others who wish to make use of this method.
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Affiliation(s)
- Huan Wang
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People's Republic of China
- Beijing National Laboratory for Molecular Sciences, Center for Spectroscopy, Beijing Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, National Biomedical Imaging Center, Peking University, Beijing 100871, People's Republic of China
| | - Zhun Xu
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Sheng Mao
- Department of Mechanics and Engineering Sciences, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Steve Granick
- Center for Soft and Living Matter, Institute for Basic Science, Ulsan, Korea, 44919
- Department of Chemistry and Physics, Ulsan National Institute of Science and Technology, Ulsan, Korea 44919
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8
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Tracking single adatoms in liquid in a transmission electron microscope. Nature 2022; 609:942-947. [PMID: 35896149 DOI: 10.1038/s41586-022-05130-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 07/20/2022] [Indexed: 02/01/2023]
Abstract
Single atoms or ions on surfaces affect processes from nucleation1 to electrochemical reactions2 and heterogeneous catalysis3. Transmission electron microscopy is a leading approach for visualizing single atoms on a variety of substrates4,5. It conventionally requires high vacuum conditions, but has been developed for in situ imaging in liquid and gaseous environments6,7 with a combined spatial and temporal resolution that is unmatched by any other method-notwithstanding concerns about electron-beam effects on samples. When imaging in liquid using commercial technologies, electron scattering in the windows enclosing the sample and in the liquid generally limits the achievable resolution to a few nanometres6,8,9. Graphene liquid cells, on the other hand, have enabled atomic-resolution imaging of metal nanoparticles in liquids10. Here we show that a double graphene liquid cell, consisting of a central molybdenum disulfide monolayer separated by hexagonal boron nitride spacers from the two enclosing graphene windows, makes it possible to monitor, with atomic resolution, the dynamics of platinum adatoms on the monolayer in an aqueous salt solution. By imaging more than 70,000 single adatom adsorption sites, we compare the site preference and dynamic motion of the adatoms in both a fully hydrated and a vacuum state. We find a modified adsorption site distribution and higher diffusivities for the adatoms in the liquid phase compared with those in vacuum. This approach paves the way for in situ liquid-phase imaging of chemical processes with single-atom precision.
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9
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Gebauer D, Gale JD, Cölfen H. Crystal Nucleation and Growth of Inorganic Ionic Materials from Aqueous Solution: Selected Recent Developments, and Implications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107735. [PMID: 35678091 DOI: 10.1002/smll.202107735] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/07/2022] [Indexed: 05/27/2023]
Abstract
In this review article, selected, latest theoretical, and experimental developments in the field of nucleation and crystal growth of inorganic materials from aqueous solution are highlighted, with a focus on literature after 2015 and on non-classical pathways. A key point is to emphasize the so far underappreciated role of water and solvent entropy in crystallization at all stages from solution speciation through to the final crystal. While drawing on examples from current inorganic materials where non-classical behavior has been proposed, the potential of these approaches to be adapted to a wide-range of systems is also discussed, while considering the broader implications of the current re-assessment of pathways for crystallization. Various techniques that are suitable for the exploration of crystallization pathways in aqueous solution, from nucleation to crystal growth are summarized, and a flow chart for the assignment of specific theories based on experimental observations is proposed.
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Affiliation(s)
- Denis Gebauer
- Leibniz University Hannover, Institute of Inorganic Chemistry, Callinstr. 9, 30167, Hannover, Germany
| | - Julian D Gale
- Curtin Institute for Computation/The Institute for Geoscience Research (TiGER), School of Molecular and Life Sciences, Curtin University, PO Box U1987, Perth, Western Australia, 6845, Australia
| | - Helmut Cölfen
- University of Konstanz, Physical Chemistry, Universitätsstr. 10, 78465, Konstanz, Germany
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10
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King M, Avaro JT, Peter C, Hauser K, Gebauer D. Solvent-mediated isotope effects strongly influence the early stages of calcium carbonate formation: exploring D 2O vs. H 2O in a combined computational and experimental approach. Faraday Discuss 2022; 235:36-55. [PMID: 35388817 DOI: 10.1039/d1fd00078k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In experimental studies, heavy water (D2O) is employed, e.g., so as to shift the spectroscopic solvent background, but any potential effects of this solvent exchange on reaction pathways are often neglected. While the important role of light water (H2O) during the early stages of calcium carbonate formation has been realized, studies into the actual effects of aqueous solvent exchanges are scarce. Here, we present a combined computational and experimental approach to start to fill this gap. We extended a suitable force field for molecular dynamics (MD) simulations. Experimentally, we utilised advanced titration assays and time-resolved attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. We find distinct effects in various mixtures of the two aqueous solvents, and in pure H2O or D2O. Disagreements between the computational results and experimental data regarding the stabilities of ion associates might be due to the unexplored role of HDO, or an unprobed complex phase behaviour of the solvent mixtures in the simulations. Altogether, however, our data suggest that calcium carbonate formation might proceed "more classically" in D2O. Also, there are indications for the formation of new structures in amorphous and crystalline calcium carbonates. There is huge potential towards further improving the understanding of mineralization mechanisms by studying solvent-mediated isotope effects, also beyond calcium carbonate. Last, it must be appreciated that H2O and D2O have significant, distinct effects on mineralization mechanisms, and that care has to be taken when experimental data from D2O studies are used, e.g., for the development of H2O-based computer models.
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Affiliation(s)
- Michael King
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Jonathan T Avaro
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany.,Empa, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Christine Peter
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Karin Hauser
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Denis Gebauer
- Institute of Inorganic Chemistry, Leibniz University of Hannover, Callinstr. 9, 30167 Hannover, Germany.
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