1
|
Bao N, Liu Q, Reynolds M, Figueras M, Smith E, Wang W, Cao M, Muller D, Mavrikakis M, Cohen I, McEuen P, Abbott N. Gas-phase microactuation using kinetically controlled surface states of ultrathin catalytic sheets. Proc Natl Acad Sci U S A 2023; 120:e2221740120. [PMID: 37126707 PMCID: PMC10175785 DOI: 10.1073/pnas.2221740120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/14/2023] [Indexed: 05/03/2023] Open
Abstract
Biological systems convert chemical energy into mechanical work by using protein catalysts that assume kinetically controlled conformational states. Synthetic chemomechanical systems using chemical catalysis have been reported, but they are slow, require high temperatures to operate, or indirectly perform work by harnessing reaction products in liquids (e.g., heat or protons). Here, we introduce a bioinspired chemical strategy for gas-phase chemomechanical transduction that sequences the elementary steps of catalytic reactions on ultrathin (<10 nm) platinum sheets to generate surface stresses that directly drive microactuation (bending radii of 700 nm) at ambient conditions (T = 20 °C; Ptotal = 1 atm). When fueled by hydrogen gas and either oxygen or ozone gas, we show how kinetically controlled surface states of the catalyst can be exploited to achieve fast actuation (600 ms/cycle) at 20 °C. We also show that the approach can integrate photochemically controlled reactions and can be used to drive the reconfiguration of microhinges and complex origami- and kirigami-based microstructures.
Collapse
Affiliation(s)
- Nanqi Bao
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY14853
| | - Qingkun Liu
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY14853
| | - Michael F. Reynolds
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY14853
| | - Marc Figueras
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI53706
| | - Evangelos Smith
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI53706
| | - Wei Wang
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY14853
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY14853
| | - Michael C. Cao
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY14853
| | - David A. Muller
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY14853
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY14853
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI53706
| | - Itai Cohen
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY14853
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY14853
| | - Paul L. McEuen
- Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY14853
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY14853
| | - Nicholas L. Abbott
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY14853
| |
Collapse
|
2
|
Zeininger J, Winkler P, Raab M, Suchorski Y, Prieto MJ, Tănase LC, de Souza Caldas L, Tiwari A, Schmidt T, Stöger-Pollach M, Steiger-Thirsfeld A, Roldan Cuenya B, Rupprechter G. Pattern Formation in Catalytic H 2 Oxidation on Rh: Zooming in by Correlative Microscopy. ACS Catal 2022; 12:11974-11983. [PMID: 36249872 PMCID: PMC9552168 DOI: 10.1021/acscatal.2c03692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/31/2022] [Indexed: 11/29/2022]
Abstract
![]()
Spatio-temporal nonuniformities in H2 oxidation
on individual
Rh(h k l) domains of a polycrystalline Rh foil were studied in the 10–6 mbar pressure range by photoemission electron microscopy
(PEEM), X-ray photoemission electron microscopy (XPEEM), and low-energy
electron microscopy (LEEM). The latter two were used for in situ correlative
microscopy to zoom in with significantly higher lateral resolution,
allowing detection of an unusual island-mediated oxygen front propagation
during kinetic transitions. The origin of the island-mediated front
propagation was rationalized by model calculations based on a hybrid
approach of microkinetic modeling and Monte Carlo simulations.
Collapse
Affiliation(s)
- Johannes Zeininger
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Philipp Winkler
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Maximilian Raab
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Yuri Suchorski
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Mauricio J. Prieto
- Department of Interface Science, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Liviu C. Tănase
- Department of Interface Science, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Lucas de Souza Caldas
- Department of Interface Science, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Aarti Tiwari
- Department of Interface Science, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Thomas Schmidt
- Department of Interface Science, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Michael Stöger-Pollach
- University Service Center for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Andreas Steiger-Thirsfeld
- University Service Center for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Beatriz Roldan Cuenya
- Department of Interface Science, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
| | - Günther Rupprechter
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| |
Collapse
|
3
|
Bartlett S, Louapre D. Provenance of life: Chemical autonomous agents surviving through associative learning. Phys Rev E 2022; 106:034401. [PMID: 36266823 DOI: 10.1103/physreve.106.034401] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/21/2022] [Indexed: 06/16/2023]
Abstract
We present a benchmark study of autonomous, chemical agents exhibiting associative learning of an environmental feature. Associative learning systems have been widely studied in cognitive science and artificial intelligence but are most commonly implemented in highly complex or carefully engineered systems, such as animal brains, artificial neural networks, DNA computing systems, and gene regulatory networks, among others. The ability to encode environmental information and use it to make simple predictions is a benchmark of biological resilience and underpins a plethora of adaptive responses in the living hierarchy, spanning prey animal species anticipating the arrival of predators to epigenetic systems in microorganisms learning environmental correlations. Given the ubiquitous and essential presence of learning behaviors in the biosphere, we aimed to explore whether simple, nonliving dissipative structures could also exhibit associative learning. Inspired by previous modeling of associative learning in chemical networks, we simulated simple systems composed of long- and short-term memory chemical species that could encode the presence or absence of temporal correlations between two external species. The ability to learn this association was implemented in Gray-Scott reaction-diffusion spots, emergent chemical patterns that exhibit self-replication and homeostasis. With the novel ability of associative learning, we demonstrate that simple chemical patterns can exhibit a broad repertoire of lifelike behavior, paving the way for in vitro studies of autonomous chemical learning systems, with potential relevance to artificial life, origins of life, and systems chemistry. The experimental realization of these learning behaviors in protocell or coacervate systems could advance a new research direction in astrobiology, since our system significantly reduces the lower bound on the required complexity for autonomous chemical learning.
Collapse
Affiliation(s)
- Stuart Bartlett
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA and Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - David Louapre
- Ubisoft Entertainment, 94160 Saint-Mandé, France and Science Étonnante, 75014 Paris, France†
| |
Collapse
|
4
|
Winkler P, Zeininger J, Raab M, Suchorski Y, Steiger-Thirsfeld A, Stöger-Pollach M, Amati M, Gregoratti L, Grönbeck H, Rupprechter G. Coexisting multi-states in catalytic hydrogen oxidation on rhodium. Nat Commun 2021; 12:6517. [PMID: 34764290 PMCID: PMC8586342 DOI: 10.1038/s41467-021-26855-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/18/2021] [Indexed: 11/23/2022] Open
Abstract
Catalytic hydrogen oxidation on a polycrystalline rhodium foil used as a surface structure library is studied by scanning photoelectron microscopy (SPEM) in the 10-6 mbar pressure range, yielding spatially resolved X-ray photoemission spectroscopy (XPS) measurements. Here we report an observation of a previously unknown coexistence of four different states on adjacent differently oriented domains of the same Rh sample at the exactly same conditions. A catalytically active steady state, a catalytically inactive steady state and multifrequential oscillating states are simultaneously observed. Our results thus demonstrate the general possibility of multi-states in a catalytic reaction. This highly unusual behaviour is explained on the basis of peculiarities of the formation and depletion of subsurface oxygen on differently structured Rh surfaces. The experimental findings are supported by mean-field micro-kinetic modelling. The present observations raise the interdisciplinary question of how self-organising dynamic processes in a heterogeneous system are influenced by the permeability of the borders confining the adjacent regions.
Collapse
Affiliation(s)
- P Winkler
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - J Zeininger
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - M Raab
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - Y Suchorski
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - A Steiger-Thirsfeld
- University Service Center for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10, 1040, Vienna, Austria
| | - M Stöger-Pollach
- University Service Center for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10, 1040, Vienna, Austria
| | - M Amati
- Elettra-Sincrotrone Trieste S.C.p.A., SS14 - km 163.5 in Area Science Park, 34149, Trieste, Italy
| | - L Gregoratti
- Elettra-Sincrotrone Trieste S.C.p.A., SS14 - km 163.5 in Area Science Park, 34149, Trieste, Italy
| | - H Grönbeck
- Department of Physics and Competence Center for Catalysis, Chalmers University of Technology, 412 96, Göteborg, Sweden
| | - G Rupprechter
- Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria.
| |
Collapse
|
5
|
Possible roadmap to advancing the knowledge system and tackling challenges from complexity. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116548] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
6
|
Andreeva AB, Le KN, Chen L, Kellman ME, Hendon CH, Brozek CK. Soft Mode Metal-Linker Dynamics in Carboxylate MOFs Evidenced by Variable-Temperature Infrared Spectroscopy. J Am Chem Soc 2020; 142:19291-19299. [DOI: 10.1021/jacs.0c09499] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anastasia B. Andreeva
- Department of Chemistry and Biochemistry, Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Khoa N. Le
- Department of Chemistry and Biochemistry, Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Lihaokun Chen
- Department of Chemistry and Biochemistry, Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Michael E. Kellman
- Department of Chemistry and Biochemistry, Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Christopher H. Hendon
- Department of Chemistry and Biochemistry, Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Carl K. Brozek
- Department of Chemistry and Biochemistry, Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, United States
| |
Collapse
|
7
|
Barroo C, Wang ZJ, Schlögl R, Willinger MG. Imaging the dynamics of catalysed surface reactions by in situ scanning electron microscopy. Nat Catal 2019. [DOI: 10.1038/s41929-019-0395-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
8
|
Huang WL, Li J, Chen X. 110th Anniversary: Mesoscale Complexity—To Dodge or To Confront? Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b01655] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wen Lai Huang
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People’s Republic of China
| | - Jinghai Li
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People’s Republic of China
| | - Xiaosong Chen
- School of Systems Science, Beijing Normal University, Beijing, 100875, People’s Republic of China
| |
Collapse
|
9
|
Huang WL, Li J, Liu Z, Zhou J, Ma C, Wen LX. Mesoscale distribution of adsorbates in ZSM-5 zeolite. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2018.09.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
10
|
Suchorski Y, Datler M, Bespalov I, Zeininger J, Stöger-Pollach M, Bernardi J, Grönbeck H, Rupprechter G. Surface-Structure Libraries: Multifrequential Oscillations in Catalytic Hydrogen Oxidation on Rhodium. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:4217-4227. [PMID: 31057690 PMCID: PMC6494118 DOI: 10.1021/acs.jpcc.8b11421] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/18/2019] [Indexed: 05/18/2023]
Abstract
Multifrequential oscillating spatiotemporal patterns in the catalytic hydrogen oxidation on rhodium have been observed in situ in the 10-6 mbar pressure range using photoemission electron microscopy. The effect is manifested by periodic chemical waves, which travel over the polycrystalline Rh surface and change their oscillation frequency while crossing boundaries between different Rh(hkl) domains. Each crystallographically specific μm-sized Rh(hkl) domain exhibits an individual wave pattern and oscillation frequency, despite the global diffusional coupling of the surface reaction, altogether creating a structure library. This unique reaction behavior is attributed to the ability of stepped surfaces of high-Miller-index domains to facilitate the formation of subsurface oxygen, serving as a feedback mechanism of kinetic oscillations. Formation of a network of subsurface oxygen as a result of colliding reaction fronts was observed in situ. Microkinetic model analysis was used to rationalize the observed effects and to reveal the relation between the barriers for surface oxidation and oscillation frequency. Structural limits of the oscillations, the existence range of oscillations, as well as the effect of varying hydrogen pressure are demonstrated.
Collapse
Affiliation(s)
- Yuri Suchorski
- Institute
of Materials Chemistry, Technische Universität
Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Martin Datler
- Institute
of Materials Chemistry, Technische Universität
Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Ivan Bespalov
- Institute
of Materials Chemistry, Technische Universität
Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Johannes Zeininger
- Institute
of Materials Chemistry, Technische Universität
Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | | | - Johannes Bernardi
- USTEM, Technische Universität Wien, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
| | - Henrik Grönbeck
- Department
of Physics and Competence Centre for Catalysis, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Günther Rupprechter
- Institute
of Materials Chemistry, Technische Universität
Wien, Getreidemarkt 9, 1060 Vienna, Austria
| |
Collapse
|
11
|
Chen J, Chen Y, Kapral R. Chemically Propelled Motors Navigate Chemical Patterns. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1800028. [PMID: 30250781 PMCID: PMC6145410 DOI: 10.1002/advs.201800028] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 04/15/2018] [Indexed: 05/06/2023]
Abstract
Very small synthetic motors that use chemical reactions to drive their motion are being studied widely because of their potential applications, which often involve active transport and dynamics on nanoscales. Like biological molecular machines, they must be able to perform their tasks in complex, highly fluctuating environments that can form chemical patterns with diverse structures. Motors in such systems can actively assemble into dynamic clusters and other unique nonequilibrium states. It is shown how chemical patterns with small characteristic dimensions may be utilized to suppress rotational Brownian motions of motors and guide them to move along prescribed paths, properties that can be exploited in applications. In systems with larger pattern length scales, domains can serve as catch basins for motors through chemotactic effects. The resulting collective motor dynamics in such confining domains can be used to explore new aspects of active particle collective dynamics or promote specific types of active self-assembly. More generally, when chemically self-propelled motors operate in far-from-equilibrium active chemical media the variety of possible phenomena and the scope of their potential applications are substantially increased.
Collapse
Affiliation(s)
- Jiang‐Xing Chen
- Department of PhysicsHangzhou Dianzi UniversityHangzhou310018China
| | - Yu‐Guo Chen
- Department of PhysicsHangzhou Dianzi UniversityHangzhou310018China
| | - Raymond Kapral
- Chemical Physics Theory GroupDepartment of ChemistryUniversity of TorontoTorontoOntarioM5S 3H6Canada
| |
Collapse
|
12
|
Sun F, Huang WL, Li J. Mesoscale Structures in the Adlayer of A-B 2 Heterogeneous Catalysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11582-11589. [PMID: 28732446 DOI: 10.1021/acs.langmuir.7b01930] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This article explores the adsorbate distributions in the adlayer for a model A-B2 system of heterogeneous catalysis, i.e., A + 1/2B2 → AB, via kinetic Monte Carlo (KMC) simulations. In comparison with our previous work on the A-B model (Sun, F.; Huang, W.; Li, J. Structural characteristics of the adlayer in heterogeneous catalysis. Chem. Eng. Sci. 2016, 153, 87-92), species B2 here brings about significant new features due to its special site requirement during adsorption and desorption and a different stoichiometric ratio in reactions. The effects of various kinetic processes on the adsorbate distribution are found to be similar to those in the A-B system; that is, both desorption and diffusion (besides adsorption) processes contribute to the adlayer uniformity while reactions account for clustering. However, desorption exhibits a stronger role than diffusion in homogenizing the adlayer, which is opposite to the finding in the previous A-B model. Under a fixed partial pressure, different reaction and desorption rate constants can lead to steady states with different dominant species, which has not been observed in the A-B system. The regime of species B poisoning shrinks as well, leading to the spreading of the coexisting regime, in comparison with the A-B model.
Collapse
Affiliation(s)
- Fei Sun
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences , Beijing 100049, People's Republic of China
| | - Wen Lai Huang
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| | - Jinghai Li
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences , Beijing 100190, People's Republic of China
| |
Collapse
|
13
|
Affiliation(s)
- Robert Schlögl
- Fritz-Haber-Institut der Max-Planck-Gesellschaft; Faradayweg 4-6 14195 Berlin Germany
- Max Planck Institute for Chemical Energy Conversion; Stiftstr. 34-36 45470 Mülheim an der Ruhr Germany
| |
Collapse
|
14
|
Affiliation(s)
- F. McBride
- Department of Chemistry, Surface Science Research Centre, University of Liverpool, Liverpool L69 3BX, UK
| | - A. Hodgson
- Department of Chemistry, Surface Science Research Centre, University of Liverpool, Liverpool L69 3BX, UK
| |
Collapse
|
15
|
Mesoscale model for heterogeneous catalysis based on the principle of compromise in competition. Chem Eng Sci 2016. [DOI: 10.1016/j.ces.2016.03.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
16
|
Brozek CK, Michaelis V, Ong TC, Bellarosa L, López N, Griffin RG, Dincă M. Dynamic DMF Binding in MOF-5 Enables the Formation of Metastable Cobalt-Substituted MOF-5 Analogues. ACS CENTRAL SCIENCE 2015; 1:252-60. [PMID: 27162979 PMCID: PMC4827552 DOI: 10.1021/acscentsci.5b00247] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Indexed: 04/14/2023]
Abstract
Multinuclear solid-state nuclear magnetic resonance, mass spectrometry, first-principles molecular dynamics simulations, and other complementary evidence reveal that the coordination environment around the Zn(2+) ions in MOF-5, one of the most iconic materials among metal-organic frameworks (MOFs), is not rigid. The Zn(2+) ions bind solvent molecules, thereby increasing their coordination number, and dynamically dissociate from the framework itself. On average, one ion in each cluster has at least one coordinated N,N-dimethylformamide (DMF) molecule, such that the formula of as-synthesized MOF-5 is defined as Zn4O(BDC)3(DMF) x (x = 1-2). Understanding the dynamic behavior of MOF-5 leads to a rational low-temperature cation exchange approach for the synthesis of metastable Zn4-x Co x O(terephthalate)3 (x > 1) materials, which have not been accessible through typical high-temperature solvothermal routes thus far.
Collapse
Affiliation(s)
- Carl K. Brozek
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Vladimir
K. Michaelis
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Ta-Chung Ong
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Luca Bellarosa
- Institute
of Chemical Research of Catalonia, ICIQ, Avinguda dels Països Catalans 16, 43007, Tarragona, Spain
| | - Núria López
- Institute
of Chemical Research of Catalonia, ICIQ, Avinguda dels Països Catalans 16, 43007, Tarragona, Spain
| | - Robert G. Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Mircea Dincă
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- E-mail:
| |
Collapse
|
17
|
Kudernatsch W, Peng G, Zeuthen H, Bai Y, Merte LR, Lammich L, Besenbacher F, Mavrikakis M, Wendt S. Direct Visualization of Catalytically Active Sites at the FeO-Pt(111) Interface. ACS NANO 2015; 9:7804-7814. [PMID: 26027877 DOI: 10.1021/acsnano.5b02339] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Within the area of surface science, one of the "holy grails" is to directly visualize a chemical reaction at the atomic scale. Whereas this goal has been reached by high-resolution scanning tunneling microscopy (STM) in a number of cases for reactions occurring at flat surfaces, such a direct view is often inhibited for reaction occurring at steps and interfaces. Here we have studied the CO oxidation reaction at the interface between ultrathin FeO islands and a Pt(111) support by in situ STM and density functional theory (DFT) calculations. Time-lapsed STM imaging on this inverse model catalyst in O2 and CO environments revealed catalytic activity occurring at the FeO-Pt(111) interface and directly showed that the Fe-edges host the catalytically most active sites for the CO oxidation reaction. This is an important result since previous evidence for the catalytic activity of the FeO-Pt(111) interface is essentially based on averaging techniques in conjunction with DFT calculations. The presented STM results are in accord with DFT+U calculations, in which we compare possible CO oxidation pathways on oxidized Fe-edges and O-edges. We found that the CO oxidation reaction is more favorable on the oxidized Fe-edges, both thermodynamically and kinetically.
Collapse
Affiliation(s)
- Wilhelmine Kudernatsch
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Guowen Peng
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Helene Zeuthen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Yunhai Bai
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Lindsay R Merte
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Lutz Lammich
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Flemming Besenbacher
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Stefan Wendt
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University , DK-8000 Aarhus C, Denmark
| |
Collapse
|
18
|
Abstract
Formation of Turing patterns of nanoscopic length scale is simulated using molecular dynamics. Based on Fourier spectra of the concentrations of species, we compare stabilities of the structures of different wavelengths and for different intermolecular potentials. Long range attraction is shown to oppose the formation of structures. Our simulations suggest that Turing patterns can be a method of self-organization at a length scale of down to 20 molecular diameters.
Collapse
Affiliation(s)
- Piotr Dziekan
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - J S Hansen
- The Department of Science, Systems and Models, Roskilde University, DNRF Centre "Glass and Time," Universitetsvej 1, bygn. 27, DK-4000, Roskilde, Denmark
| | - Bogdan Nowakowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| |
Collapse
|
19
|
Merino P, Švec M, Martinez JI, Jelinek P, Lacovig P, Dalmiglio M, Lizzit S, Soukiassian P, Cernicharo J, Martin-Gago JA. Graphene etching on SiC grains as a path to interstellar polycyclic aromatic hydrocarbons formation. Nat Commun 2015; 5:3054. [PMID: 24448250 DOI: 10.1038/ncomms4054] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 12/03/2013] [Indexed: 12/19/2022] Open
Abstract
Polycyclic aromatic hydrocarbons as well as other organic molecules appear among the most abundant observed species in interstellar space and are key molecules to understanding the prebiotic roots of life. However, their existence and abundance in space remain a puzzle. Here we present a new top-down route to form polycyclic aromatic hydrocarbons in large quantities in space. We show that aromatic species can be efficiently formed on the graphitized surface of the abundant silicon carbide stardust on exposure to atomic hydrogen under pressure and temperature conditions analogous to those of the interstellar medium. To this aim, we mimic the circumstellar environment using ultra-high vacuum chambers and investigate the SiC surface by in situ advanced characterization techniques combined with first-principles molecular dynamics calculations. These results suggest that top-down routes are crucial to astrochemistry to explain the abundance of organic species and to uncover the origin of unidentified infrared emission features from advanced observations.
Collapse
Affiliation(s)
- P Merino
- Centro de Astrobiología INTA-CSIC, Carretera de Ajalvir, km.4, ES-28850 Madrid, Spain
| | - M Švec
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, CZ-16200 Prague, Czech Republic
| | - J I Martinez
- Instituto Ciencia de Materiales de Madrid-CSIC, c/. Sor Juana Inés de la Cruz, 3, ES-28049 Madrid, Spain
| | - P Jelinek
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, CZ-16200 Prague, Czech Republic
| | - P Lacovig
- Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, S.S. 14, Km 163.5, I-34149 Trieste, Italy
| | - M Dalmiglio
- Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, S.S. 14, Km 163.5, I-34149 Trieste, Italy
| | - S Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, S.S. 14, Km 163.5, I-34149 Trieste, Italy
| | - P Soukiassian
- 1] Commissariat à l'Energie Atomique et aux Energies Alternatives, SIMA, DSM-IRAMIS-SPEC, Bât. 462, 91191 Gif sur Yvette, France [2] Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France
| | - J Cernicharo
- Centro de Astrobiología INTA-CSIC, Carretera de Ajalvir, km.4, ES-28850 Madrid, Spain
| | - J A Martin-Gago
- 1] Centro de Astrobiología INTA-CSIC, Carretera de Ajalvir, km.4, ES-28850 Madrid, Spain [2] Instituto Ciencia de Materiales de Madrid-CSIC, c/. Sor Juana Inés de la Cruz, 3, ES-28049 Madrid, Spain
| |
Collapse
|
20
|
|
21
|
Abstract
A heterogeneous catalyst is a functional material that continually creates active sites with its reactants under reaction conditions. These sites change the rates of chemical reactions of the reactants localized on them without changing the thermodynamic equilibrium between the materials.
Collapse
Affiliation(s)
- Robert Schlögl
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany) http://www.fhi-berlin.mpg.de http://www.cec.mpg.de; Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim a.d. Ruhr (Germany).
| |
Collapse
|
22
|
Yoshida M, Kondoh H. In Situ Observation of Model Catalysts under Reaction Conditions Using X-ray Core-Level Spectroscopy. CHEM REC 2014; 14:806-18. [DOI: 10.1002/tcr.201402025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Masaaki Yoshida
- Department of Chemistry; Keio University; 3-14-1 Hiyoshi Yokohama 223-8522 Japan
| | - Hiroshi Kondoh
- Department of Chemistry; Keio University; 3-14-1 Hiyoshi Yokohama 223-8522 Japan
| |
Collapse
|
23
|
Näslund LÅ. Hydrogenation of O and OH on Pt(111): A comparison between the reaction rates of the first and the second hydrogen addition steps. J Chem Phys 2014; 140:104701. [PMID: 24628190 DOI: 10.1063/1.4867535] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- L-Å Näslund
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| |
Collapse
|
24
|
Liu F, Li Y, Sun X. Effect of internal noise on the oscillation of N2O decomposition over Cu-ZSM-5 zeolites using a stochastic description. J Chem Phys 2014; 140:044715. [PMID: 25669575 DOI: 10.1063/1.4862545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
When considering stochastic oscillations of heterogeneous catalyst systems, most researches have focused on the surface of a metal or its oxide catalysts, but there have been few studies on porous catalysts. In this work, the effects of internal noise on oscillations of N2O decomposition over Cu-ZSM-5 zeolites are investigated, using the chemical Langevin equation and a mesoscopic stochastic model. Considering that Cu-ZSM-5 particles are finely divided particles, the number of Cu ions (Ns) is proportional to the particle size at a certain Cu/Al, and the internal noise is inversely proportional to Ns. Stochastic oscillations can be observed outside the deterministic oscillatory region. Furthermore, the performance of the oscillation characterized by the signal-to-noise ratio has a maximum within the optimal size range of 4-8 nm. This suggests that a nanometer-sized zeolite may be best for oscillations.
Collapse
Affiliation(s)
- Fuliang Liu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yaping Li
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiaoming Sun
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| |
Collapse
|
25
|
Rao T, Xiao T, Hou Z. Entropy production in a mesoscopic chemical reaction system with oscillatory and excitable dynamics. J Chem Phys 2012; 134:214112. [PMID: 21663349 DOI: 10.1063/1.3598111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Stochastic thermodynamics of chemical reaction systems has recently gained much attention. In the present paper, we consider such an issue for a system with both oscillatory and excitable dynamics, using catalytic oxidation of carbon monoxide on the surface of platinum crystal as an example. Starting from the chemical Langevin equations, we are able to calculate the stochastic entropy production P along a random trajectory in the concentration state space. Particular attention is paid to the dependence of the time-averaged entropy production P on the system size N in a parameter region close to the deterministic Hopf bifurcation (HB). In the large system size (weak noise) limit, we find that P ∼ N(β) with β = 0 or 1, when the system is below or above the HB, respectively. In the small system size (strong noise) limit, P always increases linearly with N regardless of the bifurcation parameter. More interestingly, P could even reach a maximum for some intermediate system size in a parameter region where the corresponding deterministic system shows steady state or small amplitude oscillation. The maximum value of P decreases as the system parameter approaches the so-called CANARD point where the maximum disappears. This phenomenon could be qualitatively understood by partitioning the total entropy production into the contributions of spikes and of small amplitude oscillations.
Collapse
Affiliation(s)
- Ting Rao
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
| | | | | |
Collapse
|
26
|
Lysova AA, Kulikov AV, Parmon VN, Sagdeev RZ, Koptyug IV. Quantitative temperature mapping within an operating catalyst by spatially resolved 27Al NMR. Chem Commun (Camb) 2012; 48:5763-5. [DOI: 10.1039/c2cc31260c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
27
|
Rao T, Zhang Z, Hou ZH, Xin HW. Coarse-grained Simulations of Chemical Oscillation in Lattice Brusselator System. CHINESE J CHEM PHYS 2011. [DOI: 10.1088/1674-0068/24/04/425-433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
28
|
Santana-Blank L, Rodríguez-Santana E, Santana-Rodríguez K. Theoretic, experimental, clinical bases of the water oscillator hypothesis in near-infrared photobiomodulation. Photomed Laser Surg 2010; 28 Suppl 1:S41-52. [PMID: 20649429 DOI: 10.1089/pho.2009.2647] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The objective of this review is to propose and document a role for the water oscillator in near-infrared (NIR) photobiomodulation. Greater understanding of the role of the water oscillator may add to a more-coherent description of central effects of NIR light on redox centers and key transmembrane enzymes such as cytochrome c oxidase (CcO). In addition, water provides a complementary pathway for absorption and transportation of NIR energy in photobiomodulation. Because of its unexpected potential, we propose terming it the "water oscillator paradox." Photobiologic mechanisms involved in the treatment of complex diseases are discussed in light of the present state of the art.
Collapse
Affiliation(s)
- Luis Santana-Blank
- Fundalas, Foundation Interdisciplinary for Research and Development, Caracas, Venezuela.
| | | | | |
Collapse
|
29
|
Non-Gaussian noise-enhanced stochastic rate oscillations in CO oxidation on nanometer-sized Pd particles. Sci China Chem 2010. [DOI: 10.1007/s11426-010-4140-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
30
|
|
31
|
Cheng Z, Luo M, Wyrick J, Sun D, Kim D, Zhu Y, Lu W, Kim K, Einstein TL, Bartels L. Power of confinement: adsorbate dynamics on nanometer-scale exposed facets. NANO LETTERS 2010; 10:3700-3703. [PMID: 20681618 DOI: 10.1021/nl1022018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The diffusion and arrangements of CO adsorbates within nanometer-scale pores on a copper surface are investigated by low-temperature scanning tunneling microscopy. In contrast to extended terraces, confinement stabilizes dislocation lines that expose more than one-fourth of the adsorbate population to potentially more reactive adsorption configurations. Confinement allows correlation between adsorbate diffusivity and the number of adsorbates in the pore. A marked increase is found that coincides with the absence of dense films on the exposed facets. In combination, we find that in confinement CO molecules are much more likely to be at adsorption sites that allow lateral access, in contrast to the dense and uniform films on extended terraces.
Collapse
Affiliation(s)
- Zhihai Cheng
- Department of Chemistry, University of California-Riverside, Riverside, California 92521, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Nagamine Y, Yoshikawa K. Contribution of convection to spatiotemporal stripe patterns formed by Ag and Sb coelectrodeposition. CHAOS (WOODBURY, N.Y.) 2010; 20:023117. [PMID: 20590313 DOI: 10.1063/1.3413962] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Various spatiotemporal patterns of dark and light stripes are formed on the surface of an electrode put in an electrolyte solution in a Ag and Sb coelectrodeposition system. In this study, we investigate the effect of natural convection of the solution on these spatiotemporal patterns. When the electrode is placed vertically, natural convection generally emerges in the electrolyte solution in the vicinity of the electrode surface during electrodeposition and flows upward along the electrode surface. When convective flow along the electrode surface was eliminated by placing the electrode horizontally, the configuration of the one-directional traveling waves (anisotropic shape) changed to an isotropic shape. This indicates that the formation of an anisotropic shape for one-directional traveling waves is due to upward convective flow along the electrode surface.
Collapse
Affiliation(s)
- Yuko Nagamine
- Spatio-Temporal Order Project, ICORP, JST, Kyoto 606-8502, Japan.
| | | |
Collapse
|
33
|
Li XZ, Probert MIJ, Alavi A, Michaelides A. Quantum nature of the proton in water-hydroxyl overlayers on metal surfaces. PHYSICAL REVIEW LETTERS 2010; 104:066102. [PMID: 20366833 DOI: 10.1103/physrevlett.104.066102] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Indexed: 05/10/2023]
Abstract
Using ab initio path-integral molecular dynamics, we show that water-hydroxyl overlayers on transition metal surfaces exhibit surprisingly pronounced quantum nuclear effects. The metal substrates serve to reduce the classical proton transfer barriers within the overlayers and, in analogy to ice under high pressure, to shorten the corresponding intermolecular hydrogen bonds. Depending on the substrate and the intermolecular separations it imposes, the traditional distinction between covalent and hydrogen bonds is lost partially [e.g., on Pt(111) and Ru(0001)] or almost entirely [e.g., on Ni(111)]. We suggest that these systems provide an excellent platform on which to systematically explore the magnitude of quantum nuclear effects in hydrogen bonds.
Collapse
Affiliation(s)
- Xin-Zheng Li
- London Centre for Nanotechnology and Department of Chemistry, University College London, London WC1E 6BT, United Kindgom
| | | | | | | |
Collapse
|
34
|
Shavorskiy A, Eralp T, Ataman E, Isvoranu C, Schnadt J, Andersen JN, Held G. Dissociation of water on oxygen-covered Rh{111}. J Chem Phys 2009; 131:214707. [DOI: 10.1063/1.3266941] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
|
35
|
Weckhuysen B. Chemical Imaging of Spatial Heterogeneities in Catalytic Solids at Different Length and Time Scales. Angew Chem Int Ed Engl 2009; 48:4910-43. [DOI: 10.1002/anie.200900339] [Citation(s) in RCA: 319] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
36
|
Weckhuysen B. Chemische Bildgebung von räumlichen Heterogenitäten in katalytischen Festkörpern auf unterschiedlichen Längen- und Zeitskalen. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200900339] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
37
|
Odagiri K, Takatsuka K. Traveling excitable waves successively generated in a nonlinear proliferation system. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:056219. [PMID: 19518548 DOI: 10.1103/physreve.79.056219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 03/18/2009] [Indexed: 05/27/2023]
Abstract
We study the dynamics of spatiotemporal pattern formation in a nonlinear proliferation system (e.g., cell division supported on a field of nutrition), in which the mechanism of activation and its self-suppression is simultaneously implemented. This dynamical model has been numerically realized with coupled cellular automata (CA), and various long-standing spatiotemporal patterns have been observed. Among others, a successive generation of traveling waves by implanting a spot of cells onto the field consisting of nutrition and activator is particularly interesting. This takes place despite the fact that the present reaction network has a stable fixed point and therefore autonomous temporal oscillatory does not exist in the mean field. Indeed, the reaction-diffusion equation method (RD) applied to this network reproduces only a single excitable wave and soon falls into a steady state (a fixed point) without the following propagating waves. This system, having a stable fixed point, is an excitable system of different kind from the FitzHugh-Nagumo model in that it can generate a pulse propagating outwards by adding only a single cell onto it from outside the system. The present excitation upon dropping a cell is amplified to macroscopic level by a hidden dynamics of oscillation between the activation and its self-suppression. A pulse thus generated is propagated in space time with the help of diffusion. Through a precise comparison between CA and RD, it is found that a very small amount of residue of the cells and activators, which are left unburned in the stochastic treatment of reactions by the CA, becomes a seed to excite the system and generate the next pulse wave. This newly born wave can leave another seed of reaction in the field after its propagation. Based on this analysis, we account for the appearance of other patterns observed. A possible control of these patterns by varying the spatial distribution of initial concentration of the relevant agents such as the activator is also discussed.
Collapse
Affiliation(s)
- Kenta Odagiri
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 153-8902 Tokyo, Japan
| | | |
Collapse
|
38
|
Matthiesen J, Wendt S, Hansen JØ, Madsen GKH, Lira E, Galliker P, Vestergaard EK, Schaub R, Laegsgaard E, Hammer B, Besenbacher F. Observation of all the intermediate steps of a chemical reaction on an oxide surface by scanning tunneling microscopy. ACS NANO 2009; 3:517-26. [PMID: 19309169 DOI: 10.1021/nn8008245] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
By means of high-resolution scanning tunneling microscopy (STM), we have revealed unprecedented details about the intermediate steps for a surface-catalyzed reaction. Specifically, we studied the oxidation of H adatoms by O(2) molecules on the rutile TiO(2)(110) surface. O(2) adsorbs and successively reacts with the H adatoms, resulting in the formation of water species. Using time-lapsed STM imaging, we have unraveled the individual reaction intermediates of HO(2), H(2)O(2), and H(3)O(2) stoichiometry and the final reaction product-pairs of water molecules, [H(2)O](2). Because of their different appearance and mobility, these four species are discernible in the time-lapsed STM images. The interpretation of the STM results is corroborated by density functional theory calculations. The presented experimental and theoretical results are discussed with respect to previous reports where other reaction mechanisms have been put forward.
Collapse
Affiliation(s)
- Jesper Matthiesen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Sharma S, Hegde MS. Ti0.99Pd0.01O2−δ: A New Pt-free Catalyst for High Rates of H2+O2Recombination with High CO Tolerant Capacity. Chemphyschem 2009; 10:637-40. [DOI: 10.1002/cphc.200800768] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
40
|
Odagiri K, Takatsuka K. Threshold effect with stochastic fluctuation in bacteria-colony-like proliferation dynamics as analyzed through a comparative study of reaction-diffusion equations and cellular automata. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:026202. [PMID: 19391815 DOI: 10.1103/physreve.79.026202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 09/07/2008] [Indexed: 05/27/2023]
Abstract
We report a comparative study on pattern formation between the methods of cellular automata (CA) and reaction-diffusion equations (RD) applying to a morphology of bacterial colony formation. To do so, we began the study with setting an extremely simple model, which was designed to realize autocatalytic proliferation of bacteria (denoted as X ) fed with nutrition (N) and their inactive state (prespore state) P1 due to starvation: X+N-->2X and X-->P1, respectively. It was found numerically that while the CA could successfully generate rich patterns ranging from the circular fat structure to the viscous-finger-like complicated one, the naive RD reproduced only the circular pattern but failed to give a finger structure. Augmenting the RD equations by adding two physical factors, (i) a threshold effect in the dynamics of X+N-->2X (breaking the continuity limit of RD) and (ii) internal noise with onset threshold (breaking the inherent symmetry of RD), we have found that the viscous-finger-like realistic patterns are indeed recovered by thus modified RD. This highlights the important difference between CA and RD, and at the same time, clarifies the necessary factors for the complicated patterns to emerge in such a surprisingly simple model system.
Collapse
Affiliation(s)
- Kenta Odagiri
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 153-8902 Tokyo, Japan
| | | |
Collapse
|
41
|
Kuck S, Wienhausen J, Hoffmann G, Wiesendanger R. A versatile variable-temperature scanning tunneling microscope for molecular growth. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:083903. [PMID: 19044360 DOI: 10.1063/1.2972971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We describe and discuss the design of a variable-temperature scanning tunneling microscope (STM) system for the study of molecules at temperatures between 18 and 300 K in ultrahigh vacuum. The STM head is a refinement of a very rigid design developed and successfully operated in Hamburg. In the current version, the head is connected to a liquid helium flow cryostat, thereby reaching a base temperature of 18 K. To minimize the heat load on the STM head, a helium back flow cooled radiation shield is installed. The dimensions and the choice of materials are based on simulations of the heat dissipation. The STM is galvanically isolated from the vacuum chamber to minimize electronic noise and mechanically decoupled by means of springs and an eddy current damping stage. Additionally, the design of the STM head allows the deposition of several molecular materials onto the same cold sample surface. The operation of the STM in imaging mode is demonstrated for TPP/Cu(111) and FePCNaClCu(111). Spectroscopic capabilities of the system are shown for electronic states on NaClCu(111) and TPP/Cu(111).
Collapse
Affiliation(s)
- Stefan Kuck
- Institute of Applied Physics, University of Hamburg, Hamburg 20355, Germany
| | | | | | | |
Collapse
|
42
|
Nagasaka M, Kondoh H, Amemiya K, Ohta T, Iwasawa Y. Proton transfer in a two-dimensional hydrogen-bonding network: water and hydroxyl on a pt(111) surface. PHYSICAL REVIEW LETTERS 2008; 100:106101. [PMID: 18352210 DOI: 10.1103/physrevlett.100.106101] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2007] [Indexed: 05/22/2023]
Abstract
The time scale of proton transfer between H(2)O and OH adsorbed on a Pt(111) surface was determined by a combination of laser-induced thermal desorption (LITD) and microscale x-ray photoelectron spectroscopy (micro-XPS). The patterned distribution OH+H(2)O/H(2)O/OH + H(2)O was initially prepared on the Pt(111) surface by the LITD method and the time evolution of the spatial distribution of H(2)O and OH was observed by the micro-XPS technique. From quantitative analyses based on a diffusion equation, we found two proton-transfer pathways with different time scales of 5.2+/-0.9 ns and 48+/-12 ns at 140 K, which were attributed to direct proton transfer to the neighbor site and H(3)O(+)-mediated transfer to the next-nearest site, respectively.
Collapse
Affiliation(s)
- M Nagasaka
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | | | |
Collapse
|
43
|
Chapter 9 Non-linear Dynamics in Catalytic Reactions. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s1573-4331(08)00009-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
44
|
Rioux RM, Hoefelmeyer JD, Grass M, Song H, Niesz K, Yang P, Somorjai GA. Adsorption and co-adsorption of ethylene and carbon monoxide on silica-supported monodisperse Pt nanoparticles: volumetric adsorption and infrared spectroscopy studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:198-207. [PMID: 18052400 DOI: 10.1021/la702685a] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The adsorption of carbon monoxide and ethylene, and their sequential adsorption, was studied over a series of Pt/SBA-15 catalysts with monodisperse particle sizes ranging from 1.7 to 7.1 nm by diffuse-reflectance infrared spectroscopy and chemisorption. Gas adsorption was dependent on the Pt particle size, temperature, and sequence of gas exposure. Adsorption of CO at room temperature on Pt/SBA-15 gives rise to a spectroscopic feature assigned to the C-O stretch: nu(CO) = 2075 cm-1 (1.9 nm); 2079 cm-1 (2.9 nm); 2082 cm-1 (3.6 nm); and 2090 cm-1 (7.1 nm). The intensity of the signal decreased in a sigmoidal fashion with increasing temperature, thereby providing semiquantitative surface coverage information. Adsorption of ethylene on Pt/SBA-15 gave rise to spectroscopic features at approximately 1340, approximately 1420, and approximately 1500 cm-1 assigned to ethylidyne, di-sigma-bonded ethylene, and pi-bonded ethylene, respectively. The ratio of these surface species is highly dependent on the Pt particle size. At room temperature, Pt particles stabilize ethylidyne as well as di-sigma- and pi-bonded ethylene; however, ethylidyne predominated on the surfaces of larger particles. Ethylidyne was the only identifiable species at 403 K, with its formation being more facile on larger particles. Co-adsorption experiments reveal that the composition of the surface layer is dependent on the order of exposure to gases. Exposure of a C2H4-covered Pt surface to CO resulted in an approximately 50% decrease in chemisorbed CO compared to a fresh Pt surface. The nu(CO) appeared at 2050 cm-1 on Pt/SBA-15 pretreated with C2H4 at room temperature. The di-sigma-bonded and pi-bonded species are the most susceptible to displacement from the surface by CO. The formation of ethylidyne appeared to be less sensitive to the presence of adsorbed carbon monoxide, especially on larger particles. Upon exposure of C2H4 to a CO-covered Pt surface, little irreversible uptake occurred due to nearly 100% site blocking. These results demonstrate that carbon monoxide competes directly with ethylene for surface sites, which will have direct implications on the poisoning of the heterogeneously catalyzed conversion of hydrocarbons.
Collapse
Affiliation(s)
- Robert M Rioux
- Department of Chemistry, University of California-Berkeley, CA 94720, USA
| | | | | | | | | | | | | |
Collapse
|
45
|
Shavorskiy A, Gladys MJ, Held G. Chemical composition and reactivity of water on hexagonal Pt-group metal surfaces. Phys Chem Chem Phys 2008; 10:6150-9. [DOI: 10.1039/b808235a] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
46
|
Juan M, Hou Z, Xin H. Theoretical Study on the Effects of Internal Noise for Rate Oscillations during CO Oxidation on Platinum(110) Surfaces. J Phys Chem A 2007; 111:11500-5. [DOI: 10.1021/jp073890e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ma Juan
- Department of Chemical Physics, Hefei National Lab of Physical Science at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Zhonghuai Hou
- Department of Chemical Physics, Hefei National Lab of Physical Science at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Houwen Xin
- Department of Chemical Physics, Hefei National Lab of Physical Science at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| |
Collapse
|
47
|
Sundarram S, Viswanathan GA, Luss D. Reactor diameter impact on hot zone dynamics in an adiabatic packed bed reactor. AIChE J 2007. [DOI: 10.1002/aic.11179] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
48
|
Kan HH, Shumbera RB, Weaver JF. Hot precursor reactions during the collisions of gas-phase oxygen atoms with deuterium chemisorbed on Pt(100). J Chem Phys 2007; 126:134704. [PMID: 17430053 DOI: 10.1063/1.2713111] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We utilized direct rate measurements and temperature programmed desorption to investigate reactions that occur during the collisions of gaseous oxygen atoms with deuterium-covered Pt(100). We find that both D2O and D2 desorb promptly when an oxygen atom beam impinges upon D-covered Pt(100) held at surface temperatures ranging from 90 to 150 K, and estimate effective cross sections of 12 and 1.8 A2, respectively, for the production of gaseous D2O and D2 at 90 K. The yields of D2O and D2 that desorb at 90 K are about 13% and 2%, respectively, of the initial D atom coverage, though most of the D2O product molecules (approximately 80%) thermalize to the surface rather than desorb at the surface temperatures studied. Increasing the surface temperature from 90 to 150 K causes the D2O desorption rate to decay more quickly during O atom exposures to the surface and results in lower yields of gaseous D2O. We attribute the production of D2O and D2 in these experiments to reactions involving intermediates that are not thermally accommodated to the surface, so-called hot precursors. The results are consistent with the production of hot D2O involving first the generation of hot OD groups from the reaction O*+D(a)-->OD*, where the asterisk denotes a hot precursor, followed by the parallel pathways OD*+D(a)-->D2O* and OD*+OD(a)-->D2O*+O(a). The final reaction contributes significantly to hot D2O production only later in the reaction period when thermalized OD groups have accumulated on the surface, and it becomes less important at higher temperature due to depletion of the OD(a) concentration by thermally activated D2O production.
Collapse
Affiliation(s)
- Heywood H Kan
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| | | | | |
Collapse
|
49
|
Abstract
In the bacterium Escherichia coli, the Min-proteins show pronounced pole-to-pole oscillations. They are functional for suppressing cell division at the cell ends, leaving the center as the only possible site for division. Analyzing different models of Min-protein dynamics in a bacterial geometry, we find waves on the cytoplasmic membrane. Interestingly, the surface wave solutions of different models belong to different symmetry classes. We suggest that experiments on Min-protein surface waves in vitro are helpful in distinguishing between different classes of models of Min-protein dynamics.
Collapse
|
50
|
Nagasaka M, Kondoh H, Nakai I, Ohta T. CO oxidation reaction on Pt(111) studied by the dynamic Monte Carlo method including lateral interactions of adsorbates. J Chem Phys 2007; 126:044704. [PMID: 17286496 DOI: 10.1063/1.2424705] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dynamics of adsorbate structures during CO oxidation on Pt(111) surfaces and its effects on the reaction were studied by the dynamic Monte Carlo method including lateral interactions of adsorbates. The lateral interaction energies between adsorbed species were calculated by the density functional theory method. Dynamic Monte Carlo simulations were performed for the oxidation reaction over a mesoscopic scale, where the experimentally determined activation energies of elementary paths were altered by the calculated lateral interaction energies. The simulated results reproduced the characteristics of the microscopic and mesoscopic scale adsorbate structures formed during the reaction, and revealed that the complicated reaction kinetics is comprehensively explained by a single reaction path affected by the surrounding adsorbates. We also propose from the simulations that weakly adsorbed CO molecules at domain boundaries promote the island-periphery specific reaction.
Collapse
Affiliation(s)
- Masanari Nagasaka
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | |
Collapse
|