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Dietrich F, Becherer M, Bellaire D, Martínez-Rodríguez P, Gerhards M. Investigating cooperative effects in small cobalt and cobalt-nickel alloy clusters with attached ethanol. Phys Chem Chem Phys 2023; 25:31077-31089. [PMID: 37946573 DOI: 10.1039/d3cp02448b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Small cationic cobalt, and cobalt-nickel alloy clusters with ethanol attached are generated in a pulsed molecular beam experiment using a laser ablation source. While the metal center is successively varied with respect to size and composition, a full-size study of these transition metal clusters is possible. The clusters are investigated via IR photodissociation spectroscopy in the region of OH- and CH-stretching vibrations. The results are compared with theoretical data obtained from DFT calculations. Both frequency shifts and structural changes according to cluster size and composition are identified and discussed in detail, also with respect to cooperative effects. Trimeric metal clusters with an uneven number of nickel atoms show evidence for C-O cleavage of the ethanol molecule. This result is elucidated by further calculations concerning the reactivity, charge and energetic distributions.
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Affiliation(s)
- Fabian Dietrich
- Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco, Chile.
- Research Center Optimas & Department of Chemistry, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Markus Becherer
- Research Center Optimas & Department of Chemistry, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Daniel Bellaire
- Research Center Optimas & Department of Chemistry, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | | | - Markus Gerhards
- Research Center Optimas & Department of Chemistry, Technische Universität Kaiserslautern, Kaiserslautern, Germany
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2
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Ulejczyk B, Nogal Ł, Młotek M, Krawczyk K. Effect of Water Content on Ethanol Steam Reforming in the Nonthermal Plasma. ACS OMEGA 2023; 8:10119-10125. [PMID: 36969476 PMCID: PMC10035005 DOI: 10.1021/acsomega.2c07431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
Ethanol steam reforming can be a source of green hydrogen. The process of producing hydrogen from ethanol is very complex. Catalysts designed for this process often become deactivated due to coke deposition. In this work, a plasma reactor was used, which is insensitive to disturbance induced by coke. The research focused on determining the influence of steam on the course of the process. The optimal water/ethanol molar ratio was found to be 4. The energy efficiency was the highest at this ratio, 22.5 mol(H2)/kW h. At the same time, a high ethanol conversion (92%) was obtained. It was also observed that the conversion of steam was many times lower than that of ethanol. However, water shortage caused a rapid increase in coke, acetylene, and ethylene production.
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Affiliation(s)
- Bogdan Ulejczyk
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Łukasz Nogal
- Faculty
of Electrical Engineering, Warsaw University
of Technology, Pl. Politechniki
1, 00-661 Warsaw, Poland
| | - Michał Młotek
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Krzysztof Krawczyk
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
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3
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Efficient Plasma Technology for the Production of Green Hydrogen from Ethanol and Water. ENERGIES 2022. [DOI: 10.3390/en15082777] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
This study concerns the production of hydrogen from a mixture of ethanol and water. The process was conducted in plasma generated by a spark discharge. The substrates were introduced in the liquid phase into the reactor. The gaseous products formed in the spark reactor were hydrogen, carbon monoxide, carbon dioxide, methane, acetylene, and ethylene. Coke was also produced. The energy efficiency of hydrogen production was 27 mol(H2)/kWh, and it was 36% of the theoretical energy efficiency. The high value of the energy efficiency of hydrogen production was obtained with relatively high ethanol conversion (63%). In the spark discharge, it was possible to conduct the process under conditions in which the ethanol conversion reached 95%. However, this entailed higher energy consumption and reduced the energy efficiency of hydrogen production to 8.8 mol(H2)/kWh. Hydrogen production increased with increasing discharge power and feed stream. However, the hydrogen concentration was very high under all tested conditions and ranged from 57.5 to 61.5%. This means that the spark reactor is a device that can feed fuel cells, the power load of which can fluctuate.
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Fukuhara S, Misawa M, Shimojo F, Shibuta Y. Ab initio molecular dynamics simulation of ethanol dissociation reactions on alloy catalysts in carbon nanotube growth. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.136619] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Fukuhara S, Shimojo F, Shibuta Y. Conformation and catalytic activity of nickel – carbon cluster for ethanol dissociation in carbon nanotube synthesis: Ab initio molecular dynamics simulation. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.04.086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Modeling the Growth of Single-Wall Carbon Nanotubes. Top Curr Chem (Cham) 2017; 375:55. [DOI: 10.1007/s41061-017-0141-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 04/16/2017] [Indexed: 10/19/2022]
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Shimamura K, Shibuta Y, Ohmura S, Arifin R, Shimojo F. Dissociation dynamics of ethylene molecules on a Ni cluster using ab initio molecular dynamics simulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:145001. [PMID: 26953616 DOI: 10.1088/0953-8984/28/14/145001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The atomistic mechanism of dissociative adsorption of ethylene molecules on a Ni cluster is investigated by ab initio molecular-dynamics simulations. The activation free energy to dehydrogenate an ethylene molecule on the Ni cluster and the corresponding reaction rate is estimated. A remarkable finding is that the adsorption energy of ethylene molecules on the Ni cluster is considerably larger than the activation free energy, which explains why the actual reaction rate is faster than the value estimated based on only the activation free energy. It is also found from the dynamic simulations that hydrogen molecules and an ethane molecule are formed from the dissociated hydrogen atoms, whereas some exist as single atoms on the surface or in the interior of the Ni cluster. On the other hand, the dissociation of the C-C bonds of ethylene molecules is not observed. On the basis of these simulation results, the nature of the initial stage of carbon nanotube growth is discussed.
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Affiliation(s)
- K Shimamura
- Department of Physics, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan. Graduate School of System Informatics, Kobe University, 1-1 Rokkodai, Nada-ku, 657-8501, Japan
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Dey G, Ren J, El-Ghazawi T, Licht S. How does an amalgamated Ni cathode affect carbon nanotube growth? A density functional theory study. RSC Adv 2016. [DOI: 10.1039/c6ra03460h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This is a Density Functional Theory (DFT) study on the influence of an alloying mixture of Ni–Zn catalysts on carbon nanotube, CNT, growth.
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Affiliation(s)
- Gangotri Dey
- Institute for Massively Parallel Applications and Computing Technology (IMPACT)
- George Washington University
- Washington DC 20052
- USA
| | - Jiawen Ren
- Department of Chemistry
- George Washington University
- Washington DC 20052
- USA
| | - Tarek El-Ghazawi
- Institute for Massively Parallel Applications and Computing Technology (IMPACT)
- George Washington University
- Washington DC 20052
- USA
| | - Stuart Licht
- Department of Chemistry
- George Washington University
- Washington DC 20052
- USA
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Ohga Y, Inoue S, Matsumura Y. In situ measurement of activation energy for pyrolysis of ethanol as a first reaction in the synthesis of carbon nanotubes. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.09.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Ab initio molecular dynamics simulation of ethanol decomposition on platinum cluster at initial stage of carbon nanotube growth. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.07.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Page AJ, Saha S, Li HB, Irle S, Morokuma K. Quantum Chemical Simulation of Carbon Nanotube Nucleation on Al2O3 Catalysts via CH4 Chemical Vapor Deposition. J Am Chem Soc 2015; 137:9281-8. [PMID: 26148208 DOI: 10.1021/jacs.5b02952] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We present quantum chemical simulations demonstrating how single-walled carbon nanotubes (SWCNTs) form, or "nucleate", on the surface of Al2O3 nanoparticles during chemical vapor deposition (CVD) using CH4. SWCNT nucleation proceeds via the formation of extended polyyne chains that only interact with the catalyst surface at one or both ends. Consequently, SWCNT nucleation is not a surface-mediated process. We demonstrate that this unusual nucleation sequence is due to two factors. First, the π interaction between graphitic carbon and Al2O3 is extremely weak, such that graphitic carbon is expected to desorb at typical CVD temperatures. Second, hydrogen present at the catalyst surface actively passivates dangling carbon bonds, preventing a surface-mediated nucleation mechanism. The simulations reveal hydrogen's reactive chemical pathways during SWCNT nucleation and that the manner in which SWCNTs form on Al2O3 is fundamentally different from that observed using "traditional" transition metal catalysts.
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Affiliation(s)
- Alister J Page
- †Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan 2308, Australia
| | - Supriya Saha
- †Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan 2308, Australia
| | - Hai-Bei Li
- §School of Ocean, Shandong University, Weihai 264209, China
| | - Stephan Irle
- ∥Institute of Transformative Bio-Molecules (WPI-ITbM) and Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Keiji Morokuma
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
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Page AJ, Ding F, Irle S, Morokuma K. Insights into carbon nanotube and graphene formation mechanisms from molecular simulations: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:036501. [PMID: 25746411 DOI: 10.1088/0034-4885/78/3/036501] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The discovery of carbon nanotubes (CNTs) and graphene over the last two decades has heralded a new era in physics, chemistry and nanotechnology. During this time, intense efforts have been made towards understanding the atomic-scale mechanisms by which these remarkable nanostructures grow. Molecular simulations have made significant contributions in this regard; indeed, they are responsible for many of the key discoveries and advancements towards this goal. Here we review molecular simulations of CNT and graphene growth, and in doing so we highlight the many invaluable insights gained from molecular simulations into these complex nanoscale self-assembly processes. This review highlights an often-overlooked aspect of CNT and graphene formation-that the two processes, although seldom discussed in the same terms, are in fact remarkably similar. Both can be viewed as a 0D → 1D → 2D transformation, which converts carbon atoms (0D) to polyyne chains (1D) to a complete sp(2)-carbon network (2D). The difference in the final structure (CNT or graphene) is determined only by the curvature of the catalyst and the strength of the carbon-metal interaction. We conclude our review by summarizing the present shortcomings of CNT/graphene growth simulations, and future challenges to this important area.
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Affiliation(s)
- A J Page
- Newcastle Institute for Energy and Resources, The University of Newcastle, Callaghan 2308, Australia
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Inoue S, Nakahara D, Matsumura Y. Precursor and formation mechanism in the synthesis of carbon nanotubes by chemical vapor deposition. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.10.062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Shibuta Y, Arifin R, Shimamura K, Oguri T, Shimojo F, Yamaguchi S. Low reactivity of methane on copper surface during graphene synthesis via CVD process: Ab initio molecular dynamics simulation. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.06.058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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