1
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Du Q, Huang L, Fu J, Cao Y, Xing X, Zhao J. Single atom alloy clusters Ag n-1X - (X = Cu, Au; n = 7-20) reacting with O 2: Symmetry-adapted orbital model. J Chem Phys 2023; 158:014306. [PMID: 36610979 DOI: 10.1063/5.0124095] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Single atom alloy AgCu catalysts have attracted great attention, since doping the single Cu atom introduces narrow free-atom-like Cu 3d states in the electronic structure. These peculiar electronic states can reduce the activation energies in some reactions and offer valuable guidelines for improving catalytic performance. However, the geometric tuning effect of single Cu atoms in Ag catalysts and the structure-activity relationship of AgCu catalysts remain unclear. Here, we prepared well-resolved pristine Agn - as well as single atom alloy Agn-1Cu- and Agn-1Au- (n = 7-20) clusters and investigated their reactivity with O2. We found that replacing an Ag atom in Agn - (n = 15-18) with a Cu atom significantly increases the reactivity with O2, while replacement of an Ag with an Au atom has negligible effects. The adsorption of O2 on Agn - or Agn-1Cu- clusters follows the single electron transfer mechanism, in which the cluster activity is dependent on two descriptors, the energy level of α-HOMO (strong correlation) and the α-HOMO-LUMO gap (weak correlation). Our calculation demonstrated that the cluster arrangements caused by single Cu atom alloying would affect the above activity descriptors and, therefore, regulates clusters' chemical activity. In addition, the observed reactivity of clusters in the representative sizes with n = 17-19 can also be interpreted using the symmetry-adapted orbital model. Our work provides meaningful information to understand the chemical activities of related single-atom-alloy catalysts.
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Affiliation(s)
- Qiuying Du
- College of Physics and Electronic Information, Inner Mongolia Normal University, 81 Zhaowuda Road, Hohhot, Inner Mongolia 010022, People's Republic of China
| | - Lulu Huang
- Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai 200092, People's Republic of China
| | - Jiaqi Fu
- College of Physics and Electronic Information, Inner Mongolia Normal University, 81 Zhaowuda Road, Hohhot, Inner Mongolia 010022, People's Republic of China
| | - Yongjun Cao
- College of Physics and Electronic Information, Inner Mongolia Normal University, 81 Zhaowuda Road, Hohhot, Inner Mongolia 010022, People's Republic of China
| | - Xiaopeng Xing
- Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai 200092, People's Republic of China
| | - Jijun Zhao
- Key Laboratory of Material Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, People's Republic of China
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2
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Mattsson S, Paulus B. First principle calculations including ab initio molecular dynamics studies for the activation of hydrogen fluoride on Ni(111). Chem Phys 2022. [DOI: 10.1016/j.chemphys.2022.111469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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3
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Xue M, Zhang L, Guo X, Wang N, Huang S. Promotion Effect of Pt-Substituted Rh55 Cluster Toward NO Adsorption and Dissociation: A First-Principles Study. J CLUST SCI 2021. [DOI: 10.1007/s10876-020-01831-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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4
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Papanikolaou KG, Stamatakis M. The catalytic decomposition of nitrous oxide and the NO + CO reaction over Ni/Cu dilute and single atom alloy surfaces: first-principles microkinetic modelling. Catal Sci Technol 2021. [DOI: 10.1039/d1cy00011j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Density functional theory calculations and microkinetic modelling reveal that well-engineered Ni/Cu dilute alloys are promising for the catalytic reduction of NO by CO.
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Affiliation(s)
| | - Michail Stamatakis
- Thomas Young Centre and Department of Chemical Engineering
- University College London
- London WC1E 7JE
- UK
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5
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Hannagan RT, Giannakakis G, Flytzani-Stephanopoulos M, Sykes ECH. Single-Atom Alloy Catalysis. Chem Rev 2020; 120:12044-12088. [DOI: 10.1021/acs.chemrev.0c00078] [Citation(s) in RCA: 286] [Impact Index Per Article: 71.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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6
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Kusada K, Wu D, Kitagawa H. New Aspects of Platinum Group Metal‐Based Solid‐Solution Alloy Nanoparticles: Binary to High‐Entropy Alloys. Chemistry 2020; 26:5105-5130. [DOI: 10.1002/chem.201903928] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/18/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Kohei Kusada
- Division of Chemistry Graduate School of Science Kyoto University 606-8502 Kyoto Japan
| | - Dongshuang Wu
- Division of Chemistry Graduate School of Science Kyoto University 606-8502 Kyoto Japan
| | - Hiroshi Kitagawa
- Division of Chemistry Graduate School of Science Kyoto University 606-8502 Kyoto Japan
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7
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Hannagan RT, Patel DA, Cramer LA, Schilling AC, Ryan PTP, Larson AM, Çınar V, Wang Y, Balema TA, Sykes ECH. Combining STM, RAIRS and TPD to Decipher the Dispersion and Interactions Between Active Sites in RhCu Single‐Atom Alloys. ChemCatChem 2019. [DOI: 10.1002/cctc.201901488] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Dipna A. Patel
- Department of Chemistry Tufts University Medford MA-02155 USA
| | - Laura A. Cramer
- Department of Chemistry Tufts University Medford MA-02155 USA
| | | | - Paul T. P. Ryan
- Diamond Light Source Harwell Science and Innovation Campus Didcot Oxfordshire OX11 0DE UK
- Department of Materials Imperial College South Kensington London SW7 2AZ UK
| | | | - Volkan Çınar
- Department of Chemistry Tufts University Medford MA-02155 USA
| | - Yicheng Wang
- Department of Chemistry Tufts University Medford MA-02155 USA
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8
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Takagi N, Ishimura K, Miura H, Shishido T, Fukuda R, Ehara M, Sakaki S. Catalysis of Cu Cluster for NO Reduction by CO: Theoretical Insight into the Reaction Mechanism. ACS OMEGA 2019; 4:2596-2609. [PMID: 31459495 PMCID: PMC6648525 DOI: 10.1021/acsomega.8b02890] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 01/10/2019] [Indexed: 06/10/2023]
Abstract
Density functional theory calculations here elucidated that Cu38-catalyzed NO reduction by CO occurred not through NO dissociative adsorption but through NO dimerization. NO is adsorbed to two Cu atoms in a bridging manner. NO adsorption energy is much larger than that of CO. N-O bond cleavage of the adsorbed NO molecule needs a very large activation energy (ΔG°‡). On the other hand, dimerization of two NO molecules occurs on the Cu38 surface with small ΔG°‡ and very negative Gibbs reaction energy (ΔG°) to form ONNO species adsorbed to Cu38. Then, a CO molecule is adsorbed at the neighboring position to the ONNO species and reacts with the ONNO to induce N-O bond cleavage with small ΔG°‡ and very negative ΔG°, leading to the formation of N2O adsorbed on Cu38 and CO2 molecule in the gas phase. N2O dissociates from Cu38, and then it is readsorbed to Cu38 in the most stable adsorption structure. N-O bond cleavage of N2O easily occurs with small ΔG°‡ and significantly negative ΔG° to form the N2 molecule and the O atom adsorbed on Cu38. The O atom reacts with the CO molecule to afford CO2 and regenerate Cu38, which is rate-determining. N2O species was experimentally observed in Cu/γ-Al2O3-catalyzed NO reduction by CO, which is consistent with this reaction mechanism. This mechanism differs from that proposed for the Rh catalyst, which occurs via N-O bond cleavage of the NO molecule. Electronic processes in the NO dimerization and the CO oxidation with the O atom adsorbed to Cu38 are discussed in terms of the charge-transfer interaction with Cu38 and Frontier orbital energy of Cu38.
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Affiliation(s)
- Nozomi Takagi
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
| | | | - Hiroki Miura
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
- Department
of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan
| | - Tetsuya Shishido
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
- Department
of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minami-osawa, Hachioji, Tokyo 192-0397, Japan
| | - Ryoichi Fukuda
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
| | - Masahiro Ehara
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
- Institute
for Molecular Science, Okazaki 444-8585, Japan
| | - Shigeyoshi Sakaki
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, 1-30 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
- Fukui
Institute for Fundamental Chemistry, Kyoto
University, 34-4 Takano-Nishihiraki-cho, Sakyo-ku, Kyoto 606-8103, Japan
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9
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Fukuda R, Sakai S, Takagi N, Matsui M, Ehara M, Hosokawa S, Tanaka T, Sakaki S. Mechanism of NO–CO reaction over highly dispersed cuprous oxide on γ-alumina catalyst using a metal–support interfacial site in the presence of oxygen: similarities to and differences from biological systems. Catal Sci Technol 2018. [DOI: 10.1039/c8cy00080h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The NO–CO reaction mechanism over the Cu/γ-Al2O3 catalyst was elucidated using DFT and a cluster model.
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Affiliation(s)
- Ryoichi Fukuda
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Shogo Sakai
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Nozomi Takagi
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Masafuyu Matsui
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Masahiro Ehara
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Saburo Hosokawa
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Tsunehiro Tanaka
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
| | - Shigeyoshi Sakaki
- Center for the Promotion of Interdisciplinary Education and Research
- Elements Strategy Initiative for Catalysts and Batteries (ESICB)
- Kyoto University
- Kyoto 615-8245
- Japan
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10
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Komatsu T, Kobayashi H, Kusada K, Kubota Y, Takata M, Yamamoto T, Matsumura S, Sato K, Nagaoka K, Kitagawa H. First-Principles Calculation, Synthesis, and Catalytic Properties of Rh-Cu Alloy Nanoparticles. Chemistry 2016; 23:57-60. [PMID: 27787925 PMCID: PMC5724656 DOI: 10.1002/chem.201604286] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Indexed: 11/08/2022]
Abstract
The first synthesis of pure Rh1−xCux solid‐solution nanoparticles is reported. In contrast to the bulk state, the solid‐solution phase was stable up to 750 °C. Based on facile density‐functional calculations, we made a prediction that the catalytic activity of Rh1−xCux can be maintained even with 50 at % replacement of Rh with Cu. The prediction was confirmed for the catalytic activities on CO and NOx conversions.
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Affiliation(s)
- Tokutaro Komatsu
- Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.,School of Medicine, Nihon University, 30-1 Oyaguchi-Kamicho, Itabashi-ku, Tokyo, 173-8610, Japan
| | - Hirokazu Kobayashi
- Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.,JST PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan
| | - Kohei Kusada
- Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yoshiki Kubota
- Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Masaki Takata
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan.,Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Tomokazu Yamamoto
- Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Syo Matsumura
- Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Katsutoshi Sato
- Department of Applied Chemistry, Faculty of Engineering, Oita University, 700 Dannoharu, Oita, 870-1192, Japan.,Center for the Promotion of Interdisciplinary Education and Research, Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, 1-30, Goryo Ohara, Nishikyo-ku, Kyoto, 615-8503, Japan
| | - Katsutoshi Nagaoka
- Department of Applied Chemistry, Faculty of Engineering, Oita University, 700 Dannoharu, Oita, 870-1192, Japan.,Center for the Promotion of Interdisciplinary Education and Research, Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, 1-30, Goryo Ohara, Nishikyo-ku, Kyoto, 615-8503, Japan
| | - Hiroshi Kitagawa
- Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.,Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan.,INAMORI Frontier Research Center, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-3095, Japan
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11
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Ellert OG, Tsodikov MV, Nikolaev SA, Novotortsev VM. Bimetallic nanoalloys in heterogeneous catalysis of industrially important reactions: synergistic effects and structural organization of active components. RUSSIAN CHEMICAL REVIEWS 2014. [DOI: 10.1070/rc2014v083n08abeh004432] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Moreno JLV, Padama AAB, Kasai H. A density functional theory-based study on the dissociation of NO on a CuO(110) surface. CrystEngComm 2014. [DOI: 10.1039/c3ce42103a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Yang L, Liu P. Ethanol Synthesis from Syngas on Transition Metal-Doped Rh(111) Surfaces: A Density Functional Kinetic Monte Carlo Study. Top Catal 2013. [DOI: 10.1007/s11244-013-0168-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Kishi H, Padama AAB, Arevalo RL, Moreno JLV, Kasai H, Taniguchi M, Uenishi M, Tanaka H, Nishihata Y. A theoretical study of the reactivity of Cu2O(111) surfaces: the case of NO dissociation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:262001. [PMID: 22692043 DOI: 10.1088/0953-8984/24/26/262001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We compare the electronic properties of Cu(111) and Cu(2)O(111) surfaces in relation to the dissociation of NO using first principles calculations within density functional theory. We note a well-defined three-fold site on both O- and Cu-terminated Cu(2)O surfaces which is verified as the active site for the adsorption and dissociation of NO. The interaction of Cu with O atoms results in the forward shifting of the local density of states and formation of unoccupied states above the Fermi level, compared to the fully occupied d band of pure Cu. These results give valuable insights in the realization of a catalyst without precious metal for the dissociation of NO.
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Affiliation(s)
- Hirofumi Kishi
- Department of Precision Science and Technology and Applied Physics, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
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15
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Padama AAB, Kishi H, Arevalo RL, Moreno JLV, Kasai H, Taniguchi M, Uenishi M, Tanaka H, Nishihata Y. NO dissociation on Cu(111) and Cu2O(111) surfaces: a density functional theory based study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:175005. [PMID: 22481123 DOI: 10.1088/0953-8984/24/17/175005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
NO dissociation on Cu(111) and Cu(2)O(111) surfaces is investigated using spin-polarized density functional theory. This is to verify the possibility of using Cu-based catalyst for NO dissociation which is the rate limiting step for the NO(x) reduction process. The dissociation of molecularly adsorbed NO on the surface is activated for both cases. However, from the reaction path of the NO-Cu(2)O(111) system, the calculated transition state lies below the reference energy which indicates the possibility of dissociation. For the NO-Cu(111) system, the reaction path shows that NO desorption is more likely to occur. The geometric and electronic structure of the Cu(2)O(111) surface indicates that the surface Cu atoms stabilize themselves with reference to the O atom in the subsurface. The interaction results in modification of the electronic structure of the surface Cu atoms of Cu(2)O(111) which greatly affects the adsorption and dissociation of NO. This phenomenon further explains the obtained differences in the dissociation pathways of NO on the surfaces.
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Affiliation(s)
- A A B Padama
- Department of Precision Science and Technology and Applied Physics, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
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16
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17
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Inderwildi OR, Jenkins SJ, King DA. Dynamic Interplay between Diffusion and Reaction: Nitrogen Recombination on Rh{211} in Car Exhaust Catalysis. J Am Chem Soc 2008; 130:2213-20. [DOI: 10.1021/ja0754913] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Oliver R. Inderwildi
- University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Stephen J. Jenkins
- University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - David A. King
- University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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18
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Gomes JRB, Gonzalez S, Torres D, Illas F. Exploring the molecular mechanisms of reactions at surfaces. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2007. [DOI: 10.1134/s1990793107040033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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González S, Sousa C, Illas F. Similarities and differences on the molecular mechanism of CO oxidation on Rh(111) and bimetallic RhCu(111) surfaces. Phys Chem Chem Phys 2007; 9:2877-85. [PMID: 17538733 DOI: 10.1039/b701024a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction between adsorbed CO and atomic O on various sites of Rh(111) and on the bimetallic RhCu(111) surface has been investigated by first principles density functional theory using slab models. The most likely reaction pathway for CO oxidation on Rh(111) involves probably migration of atomic oxygen from fcc to hcp sites. On the bimetallic surface the mechanism is similar, although depending on the type of bimetallic site a reduction of the energy barrier is predicted. Consequences for the NO reduction by CO reaction are analyzed.
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Affiliation(s)
- Silvia González
- Departament de Química Física i Centre Especial de Recerca en Química Teòrica, Universitat de Barcelona i Parc Científic de Barcelona, C/Martí i Franquès 1, 08028, Barcelona, Spain
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20
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Gutsev GL, Mochena MD, Johnson E, Bauschlicher CW. Dissociative and associative attachment of NO to iron clusters. J Chem Phys 2006; 125:194312. [PMID: 17129108 DOI: 10.1063/1.2378831] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electronic and geometrical structures of iron clusters with associative (FeNO, Fe2NO, Fe3NO, Fe4NO, Fe5NO, and Fe6NO) and dissociative (OFeN, OFe2N, OFe3N, OFe4N, OFe5N, and OFe6N) attachments of NO, as well as the corresponding singly negatively and positively charged ions, are computed using density functional theory with generalized gradient corrections. Both types of isomers are found to be stable and no spontaneous dissociation was observed during the geometry optimizations. The ground states correspond to dissociative attachment of NO for all iron clusters Fe(n), except for Fe and Fe+. All of the OFe(n)N clusters have ferrimagnetic ground states, except for OFe2N, OFe2N-, OFe4N, and OFe4N-, which prefer the ferromagnetic coupling. In the ferrimagnetic states, the excess spin density at one iron atom couples antiferromagnetically to the excess spin densities of all other iron atoms. Relative to the high-spin Fe(n) ground state, the lowest energy ferrimagnetic state quenches the total magnetic moments of iron clusters by 7, which is to be compared with a reduction in the magnetic moment of one in the lowest energy ferromagnetic states. Dissociation of NO on the iron clusters has a pronounced impact on the energetics of reactions; the Fe(n)NO+CO-->Fe(n)N+CO2 channels are exothermic while the OFe6N+CO--> Fe6N+CO2 channels are nearly thermoneutral.
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Affiliation(s)
- G L Gutsev
- Department of Physics, Florida A&M University, Tallahassee, Florida 32307, USA.
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