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Zhang L, Shan Y, Yan Z, Liu Z, Yu Y, He H. Efficient Pt/KFI zeolite catalysts for the selective catalytic reduction of NO x by hydrogen. J Environ Sci (China) 2024; 138:102-111. [PMID: 38135379 DOI: 10.1016/j.jes.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/02/2023] [Accepted: 03/02/2023] [Indexed: 12/24/2023]
Abstract
Aiming at purification of NOx from hydrogen internal combustion engines (HICEs), the hydrogen selective catalytic reduction (H2-SCR) reaction was investigated over a series of Pt/KFI zeolite catalysts. H2 can readily reduce NOx to N2 and N2O while O2 inhibited the deNOx efficiency by consuming the reductant H2. The Pt/KFI zeolite catalysts with Pt loading below 0.1 wt.% are optimized H2-SCR catalysts due to its suitable operation temperature window since high Pt loading favors the H2-O2 reaction which lead to the insufficient of reactants. Compared to metal Pt0 species, Ptδ+ species showed lower activation energy of H2-SCR reaction and thought to be as reasonable active sites. Further, Eley-Rideal (E-R) reaction mechanism was proposed as evidenced by the reaction orders in kinetic studies. Last, the optimized reactor was designed with hybrid Pt/KFI catalysts with various Pt loading which achieve a high NOx conversion in a wide temperature range.
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Affiliation(s)
- Ligang Zhang
- School of Rare Earths, University of Science and Technology of China, Hefei 230026, China; Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341119, China
| | - Yulong Shan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Zidi Yan
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341119, China
| | - Zhongqi Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yunbo Yu
- School of Rare Earths, University of Science and Technology of China, Hefei 230026, China; Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341119, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hong He
- School of Rare Earths, University of Science and Technology of China, Hefei 230026, China; Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341119, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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2
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Chen JJ, Wang SD, Li ZY, Li XN, He SG. Selective Reduction of NO into N 2 Catalyzed by Rh 1-Doped Cluster Anions RhCe 2O 3-5. J Am Chem Soc 2023; 145:18658-18667. [PMID: 37572057 DOI: 10.1021/jacs.3c06565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/14/2023]
Abstract
Catalytic conversion of toxic nitrogen oxide (NO) and carbon monoxide (CO) into nitrogen (N2) and carbon dioxide (CO2) is imperative under the weight of the increasingly stringent emission regulations, while a fundamental understanding of the nature of the active site to selectively drive N2 generation is elusive. Herein, in combination with state-of-the-art mass-spectrometric experiments and quantum-chemical calculations, we demonstrated that the rhodium-cerium oxide clusters RhCe2O3-5- can catalytically drive NO reduction by CO and give rise to N2 and CO2. This finding represents a sharp improvement in cluster science where N2O is commonly produced in the rarely established examples of catalytic NO reduction mediated with gas-phase clusters. We demonstrated the importance of the unique chemical environment in the RhCe2O3- cluster to guide the substantially improved N2 selectivity: a triatomic Lewis "acid-base-acid" Ceδ+-Rhδ--Ceδ+ site is proposed to strongly adsorb two NO molecules as well as the N2O intermediate that is attached on the Rh atom and can facilely dissociate to form N2 assisted by both Ce atoms.
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Affiliation(s)
- Jiao-Jiao Chen
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Beijing National Laboratory for Molecular Sciences and CAS Research/Education Center of Excellence in Molecular Sciences, Beijing 100190, China
| | - Si-Dun Wang
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China
| | - Zi-Yu Li
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Beijing National Laboratory for Molecular Sciences and CAS Research/Education Center of Excellence in Molecular Sciences, Beijing 100190, China
| | - Xiao-Na Li
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Beijing National Laboratory for Molecular Sciences and CAS Research/Education Center of Excellence in Molecular Sciences, Beijing 100190, China
| | - Sheng-Gui He
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing National Laboratory for Molecular Sciences and CAS Research/Education Center of Excellence in Molecular Sciences, Beijing 100190, China
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3
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Borchers M, Lott P, Deutschmann O. Selective Catalytic Reduction with Hydrogen for Exhaust gas after-treatment of Hydrogen Combustion Engines. Top Catal 2022. [DOI: 10.1007/s11244-022-01723-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
AbstractIn this work, two palladium-based catalysts with either ZSM-5 or Zeolite Y as support material are tested for their performance in selective catalytic reduction of NOx with hydrogen (H2-SCR). The ligh-toff measurements in synthetic exhaust gas mixtures typical for hydrogen combustion engines are supplemented by detailed catalyst characterization comprising N2 physisorption, X-ray powder diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR) and ammonia temperature programmed desorption (NH3-TPD). Introducing 10% or 20% TiO2 into the catalyst formulations reduced the surface area and the number of acidic sites for both catalysts, however, more severely for the Zeolite Y-supported catalysts. The higher reducibility of the Pd particles that was uncovered by H2-TPR resulted in an improved catalytic performance during the light-off measurements and substantially boosted NO conversion. Upon exposition to humid exhaust gas, the ZSM-5-supported catalysts showed a significant drop in performance, whereas the Zeolite Y-supported catalyst kept the high levels of conversion while shifting the selectivity from N2O more toward NH3 and N2. The 1%Pd/20%TiO2/HY catalyst subject to this work outperforms one of the most active and selective benchmark catalyst formulations, 1%Pd/5%V2O5/20%TiO2-Al2O3, making Zeolite Y a promising support material for H2-SCR catalyst formulations that allow efficient and selective NOx-removal from exhaust gases originating from hydrogen-fueled engines.
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4
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Bakker JM, Mafuné F. Zooming in on the initial steps of catalytic NO reduction using metal clusters. Phys Chem Chem Phys 2022; 24:7595-7610. [PMID: 35297928 PMCID: PMC8966623 DOI: 10.1039/d1cp05760j] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The study of reactions relevant to heterogeneous catalysis on the surface of well-defined metal clusters with full control over the number of consituent atoms and elemental composition can lead to a detailed insight into the interactions between metal and reactants. We here review experimental and theoretical studies involving the adsorption of NO molecules on mostly rhodium-based clusters under near-thermal conditions in a molecular beam. We show how IR spectrosopic characterization can give information on the binding nature of NO to the clusters for at least the first three NO molecules. The complementary technique of thermal desorption spectrometry reveals at what temperatures multiple NO molecules on the cluster surface desorb or combine to form rhodium oxides followed by N2 elimination. Variation of the cluster elemental composition can be a powerful method to identify how the propensity of the critical first step of NO dissociation can be increased. The testing of such concepts with atomic detail can be of great help in guiding the choices in rational catalyst design. The study of reactions relevant to heterogeneous catalysis on metal clusters with full control over the number of constituent atoms and elemental composition can lead to a detailed insight into the interactions governing catalytic functionality.![]()
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Affiliation(s)
- Joost M Bakker
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
| | - Fumitaka Mafuné
- Department of Basic Science, School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan.
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5
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Lott P, Wagner U, Koch T, Deutschmann O. Der Wasserstoffmotor – Chancen und Herausforderungen auf dem Weg zu einer dekarbonisierten Mobilität. CHEM-ING-TECH 2022. [DOI: 10.1002/cite.202100155] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Patrick Lott
- Karlsruher Institut für Technologie Institut für Technische Chemie und Polymerchemie (ITCP) Engesserstraße 20 76131 Karlsruhe Deutschland
| | - Uwe Wagner
- Karlsruher Institut für Technologie (KIT) Institut für Kolbenmaschinen (IFKM) Rintheimer Querallee 2 76131 Karlsruhe Deutschland
| | - Thomas Koch
- Karlsruher Institut für Technologie (KIT) Institut für Kolbenmaschinen (IFKM) Rintheimer Querallee 2 76131 Karlsruhe Deutschland
| | - Olaf Deutschmann
- Karlsruher Institut für Technologie Institut für Technische Chemie und Polymerchemie (ITCP) Engesserstraße 20 76131 Karlsruhe Deutschland
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6
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Ikemoto S, Muratsugu S, Koitaya T, Tada M. Chromium Oxides as Structural Modulators of Rhodium Dispersion on Ceria to Generate Active Sites for NO Reduction. ACS Catal 2021. [DOI: 10.1021/acscatal.1c03807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Satoru Ikemoto
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Satoshi Muratsugu
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi 332-0012, Japan
| | - Takanori Koitaya
- Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi 332-0012, Japan
- Department of Materials Molecular Science, Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi 444-8585, Japan
| | - Mizuki Tada
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
- Research Center for Materials Science (RCMS), Integrated Research Consortium on Chemical Sciences (IRCCS), and Institute for Advanced Study, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
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7
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Mafuné F, Bakker JM, Kudoh S. Dissociative adsorption of NO introduces flexibility in gas phase Rh6+ clusters leading to a rich isomeric distribution. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Takagi N, Ehara M, Sakaki S. Theoretical Study of NO Dissociative Adsorption onto 3d Metal Particles M 55 (M = Fe, Co, Ni, and Cu): Relation between the Reactivity and Position of the Metal Element in the Periodic Table. ACS OMEGA 2021; 6:4888-4898. [PMID: 33644596 PMCID: PMC7905950 DOI: 10.1021/acsomega.0c05838] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
NO dissociative adsorption onto 3d metal particles M55 (M = Fe, Co, Ni, and Cu) was investigated theoretically using density functional theory computations. A transition state exists at higher energy in the Cu case but at lower energy in the Fe, Co, and Ni cases than the reactant (sum of M55 and NO), indicating that Cu55 is not reactive for NO dissociative adsorption because NO desorption occurs more easily than the N-O bond cleavage in this case, but Fe55, Co55, and Ni55 are reactive because NO desorption needs a larger destabilization energy than the N-O bond cleavage. This result agrees with the experimental findings. The energy of transition state E(TS) becomes higher in the order of Fe < Co < Ni ≪ Cu. Exothermicity E exo (relative energy to the reactant) decreases in the order of Fe > Co > Ni ≫ Cu. These results indicate that the reactivity for NO dissociative adsorption decreases kinetically and thermodynamically in this order. In addition, the E(TS) and E exo values show that 3d metal particles are more reactive than 4d metal particles when a comparison is made in the same group of the periodic table. Charge transfer (CT) from the metal particle to NO increases as the reaction proceeds. The CT quantity to NO at the TS increases in the order of Cu < Ni < Co < Fe, identical to the increasing order of reactivity. The negative charges of the N and O atoms of the product (N and O adsorbed M55) increase in the order of Ni < Co < Cu < Fe, identical to the increasing order of E exo except for the Cu case; in the Cu case, the discrepancy between the order of E exo and those of the N and O negative charges arises from the presence of valence 4s electron of Cu because it suppresses the CT from N and O to Cu55. From these results, one can infer that the d-valence band-top energy of M55 plays an important role in determining the reactivity for NO dissociative adsorption. Truly, the d valence orbital energy decreases in the order of Fe > Co > Ni ≫ Cu and the 3d metal > 4d metal in the same group of the periodic table, which reflects the dependence of reactivity on the metal element position in the periodic table.
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Affiliation(s)
- Nozomi Takagi
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, Goryo-Ohara 1-30, Nishikyo-ku, Kyoto 615-8245, Japan
| | - Masahiro Ehara
- Elements
Strategy Initiative for Catalysts and Batteries, Kyoto University, Goryo-Ohara 1-30, 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, Goryo-Ohara 1-30, Nishikyo-ku, Kyoto 615-8245, Japan
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9
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Guo S, Zhang G, Han ZK, Zhang S, Sarker D, Xu WW, Pan X, Li G, Baiker A. Synergistic Effects of Ternary PdO-CeO 2-OMS-2 Catalyst Afford High Catalytic Performance and Stability in the Reduction of NO with CO. ACS APPLIED MATERIALS & INTERFACES 2021; 13:622-630. [PMID: 33356099 DOI: 10.1021/acsami.0c18451] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We developed a robust ternary PdO-CeO2-OMS-2 catalyst with excellent catalytic performance in the selective reduction of NO with CO using a strategy based on combining components that synergistically interact leading to an effective abatement of these toxic gases. The catalyst affords 100% selectivity to N2 at the nearly full conversion of NO and CO at 250 °C, high stability in the presence of H2O, and a remarkable SO2 tolerance. To unravel the origin of the excellent catalytic performance, the structural and chemical properties of the PdO-CeO2-OMS-2 nanocomposite were analyzed in the as-prepared and used state of the catalyst, employing a series of pertinent characterization methods and specific catalytic tests. The experimental as well as theoretical results, based on density-functional theory calculations suggest that CO and NO follow different reaction pathways, CO is preferentially adsorbed and oxidized at Pd sites (PdII and Pd0), while NO decomposes on the ceria surface. Lattice oxygen vacancies at the interfacial perimeter of PdO-CeO2 and PdO-OMS-2, and the diffusion of oxygen and oxygen vacancies are proposed to play a critical role in this multicenter reaction system.
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Affiliation(s)
- Song Guo
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Guomei Zhang
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
| | - Zhong-Kang Han
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, Moscow 143026, Russia
| | - Shaoyang Zhang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006, China
| | - Debalaya Sarker
- Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, Moscow 143026, Russia
| | - Wen Wu Xu
- Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China
| | - Xiaoli Pan
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Gao Li
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Alfons Baiker
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, Hönggerberg, HCl, Zurich CH-8093, Switzerland
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10
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Gong J, Pihl J, Wang D, Kim MY, Partridge WP, Li J, Cunningham M, Kamasamudram K, Currier N, Yezerets A. O2 dosage as a descriptor of TWC performance under lean/rich dithering in stoichiometric natural gas engines. Catal Today 2021. [DOI: 10.1016/j.cattod.2020.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Asokan C, Yang Y, Dang A, Getsoian A“B, Christopher P. Low-Temperature Ammonia Production during NO Reduction by CO Is Due to Atomically Dispersed Rhodium Active Sites. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01249] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chithra Asokan
- Department of Chemical Engineering, University of California, Santa Barbara, 93117 United States,
| | - Yang Yang
- Department of Chemical Engineering, University of California, Santa Barbara, 93117 United States,
| | - Alan Dang
- Department of Chemical Engineering, University of California, Santa Barbara, 93117 United States,
| | | | - Phillip Christopher
- Department of Chemical Engineering, University of California, Santa Barbara, 93117 United States,
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12
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Hu Z, Yong X, Li D, Yang RT. Synergism between palladium and nickel on Pd-Ni/TiO2 for H2-SCR: A transient DRIFTS study. J Catal 2020. [DOI: 10.1016/j.jcat.2019.11.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Zeng J, Zhong X, Yu J, Zhang T, Wang Y, Chang H. Promotional Effect of Preparation Methods on Catalytic Reduction of NO by CO over CoCeO x Catalysts. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b04232] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jie Zeng
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Xuemei Zhong
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Jie Yu
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Tao Zhang
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Yazhou Wang
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
| | - Huazhen Chang
- School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China
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14
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Takagi N, Ishimura K, Fukuda R, Ehara M, Sakaki S. Reaction Behavior of the NO Molecule on the Surface of an M n Particle (M = Ru, Rh, Pd, and Ag; n = 13 and 55): Theoretical Study of Its Dependence on Transition-Metal Element. J Phys Chem A 2019; 123:7021-7033. [PMID: 31313931 DOI: 10.1021/acs.jpca.9b04069] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reaction of NO molecule on M13 and M55 clusters (M = Ru, Rh, Pd, and Ag) was theoretically investigated to elucidate why its reaction behavior depends on the position of metal element in the periodic table. DFT computations show that NO dissociative adsorption occurs on M = Ru and Rh, NO molecular adsorption occurs on M = Pd, and NO dimerization occurs on M = Ag, which agree with experimental findings. The d-band center and d-band top become lower in energy following the order Ru > Rh > Pd > Ag; this is one of the characteristic features of the periodic table. In the Ag cluster, the valence band-top consists of Ag 5s orbital and its energy is higher than the d-band top of Pd. For NO dissociative adsorption, the M-N and M-O bond strengths are crucially important at the transition state and the product, to which the metal d orbital contributes very much. Ru and Rh clusters have a high energy d-band center and d-valence band top, leading to the formation of strong M-N and M-O bonds. Pd and Ag clusters have a low energy d-band center and d-band top, leading to the formation of weak M-N and M-O bonds. Because the Ag cluster has a high energy 5s valence band that can overlap well with the π* + π* MO of ONNO (NO dimer) moiety due to the same symmetry, charge transfer (CT) occurs from the Ag cluster to the π* + π* MO, which is indispensable for NO dimerization. The 4d-valence band top of Ru and Rh clusters does not fit to the π* + π* MO because of the different symmetry. Though the d-valence band top of the Pd cluster can overlap with the π* + π* MO, its energy is low, which is not good for the CT. Thus, the reactivity of metal cluster for NO is determined by the energy and type (4d or 5s) of the valence band top, which both depend on the position of element in the periodic table; accordingly, Ru and Rh clusters are reactive for NO dissociative adsorption, the Ag cluster is reactive for NO dimerization, but the Pd cluster is not reactive for both and only NO molecular adsorption is possible.
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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
| | | | - 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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15
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Ma H, Li S, Wang H, Schneider WF. Water-Mediated Reduction of Aqueous N-Nitrosodimethylamine with Pd. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7551-7563. [PMID: 31244058 DOI: 10.1021/acs.est.9b01425] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pd-catalyzed reduction has emerged as a promising treatment strategy to remove the recalcitrant disinfection byproduct N-nitrosodimethylamine (NDMA). However, the reaction pathways remain unexplored, and questions remain about how water solvent influences NDMA reduction mechanisms and selectivity. Here, we compute the energies and barriers of all relevant elementary steps in NDMA reduction by H2 on Pd(111) using density functional theory. We further calculate water-assisted H-shuttling for all hydrogenation reactions explicitly and include water solvation for all elementary reactions implicitly. We parametrize microkinetic models to predict product formation rates and selectivities over a wide range of NDMA concentrations. We show that H2O-mediated H-shuttling lowers the reaction barriers for all hydrogenation reactions involved in NDMA reduction while implicit solvation has negligible impact on the reaction and activation energies. We further conduct batch experiments with SiO2-supported Pd nanoparticles and compare them with the microkinetic models. The predicted rates, selectivity, and apparent activation energy from the model parametrized with both explicit H2O-mediated H-shuttling and implicit solvation correspond well with experimental observations. Models that ignore water as an H-shuttle or solvent fail to recover the experimental rates and apparent activation energy. We identified the rate-determining steps of the reaction and show the reaction flow pathways of the complicated reaction network. Finally, we demonstrate that water-mediated H-shuttling changes the rate-determining steps and reaction flows of elementary reactions.
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Affiliation(s)
- Hanyu Ma
- Department of Chemical and Biomolecular Engineering , University of Notre Dame , Notre Dame , Indiana 46556 , United States
| | - Sichi Li
- Department of Chemical and Biomolecular Engineering , University of Notre Dame , Notre Dame , Indiana 46556 , United States
| | - Haitao Wang
- School of Environmental Science and Technology , Nankai University , Tianjin 300350 , PR China
| | - William F Schneider
- Department of Chemical and Biomolecular Engineering , University of Notre Dame , Notre Dame , Indiana 46556 , United States
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16
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Hu Z, Yang RT. 110th Anniversary: Recent Progress and Future Challenges in Selective Catalytic Reduction of NO by H2 in the Presence of O2. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b01843] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Zhun Hu
- Institute of Industrial Catalysis, School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, China
- Department of Chemical Engineering, University of Michigan, 3074 H.H. Dow, 2300 Hayward Street, Ann Arbor, Michigan 48109-2136, United States
| | - Ralph T. Yang
- Department of Chemical Engineering, University of Michigan, 3074 H.H. Dow, 2300 Hayward Street, Ann Arbor, Michigan 48109-2136, United States
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17
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Jeon J, Kon KI, Toyao T, Shimizu KI, Furukawa S. Design of Pd-based pseudo-binary alloy catalysts for highly active and selective NO reduction. Chem Sci 2019; 10:4148-4162. [PMID: 31057743 PMCID: PMC6471737 DOI: 10.1039/c8sc05496g] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/04/2019] [Indexed: 12/12/2022] Open
Abstract
The development of Pd-based alloy catalysts for highly active and selective reduction of NO by CO was investigated. A survey of Pd-based bimetallic catalysts (PdM/Al2O3: M = Cu, In, Pb, Sn, and Zn) revealed that the PdIn/Al2O3 catalyst displayed excellent N2 selectivity even at low temperatures (100% at 200 °C). The catalytic activity of PdIn was further improved by substituting a part of In with Cu, where a Pd(In1-x Cu x ) pseudo-binary alloy structure was formed. The optimized catalyst, namely, Pd(In0.33Cu0.67)/Al2O3, facilitated the complete conversion of NO to N2 (100% yield) even at 200 °C and higher, which has never been achieved using metallic catalysts. The formation of the pseudo-binary alloy structure was confirmed by the combination of HAADF-STEM-EDS, EXAFS, and CO-FT-IR analyses. A detailed mechanistic study based on kinetic analysis, operando XAFS, and DFT calculations revealed the roles of In and Cu in the significant enhancement of catalytic performance: (1) N2O adsorption and decomposition (N2O → N2 + O) were drastically enhanced by In, thus resulting in high N2 selectivity; (2) CO oxidation was promoted by In, thus leading to enhanced low-temperature activity; and (3) Cu substitution improved NO adsorption and dissociation (NO → N + O), thus resulting in the promotion of high-temperature activity.
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Affiliation(s)
- Jaewan Jeon
- Institute for Catalysis , Hokkaido University , N21, W10 , Sapporo 001-0021 , Japan .
| | - Ken-Ichi Kon
- Institute for Catalysis , Hokkaido University , N21, W10 , Sapporo 001-0021 , Japan .
| | - Takashi Toyao
- Institute for Catalysis , Hokkaido University , N21, W10 , Sapporo 001-0021 , Japan .
- Elements Strategy Initiative for Catalysts and Batteries , Kyoto University , Katsura , Kyoto 615-8520 , Japan
| | - Ken-Ichi Shimizu
- Institute for Catalysis , Hokkaido University , N21, W10 , Sapporo 001-0021 , Japan .
- Elements Strategy Initiative for Catalysts and Batteries , Kyoto University , Katsura , Kyoto 615-8520 , Japan
| | - Shinya Furukawa
- Institute for Catalysis , Hokkaido University , N21, W10 , Sapporo 001-0021 , Japan .
- Elements Strategy Initiative for Catalysts and Batteries , Kyoto University , Katsura , Kyoto 615-8520 , Japan
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18
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Chen X, Lyu Y, Nwabara U, Schwank JW. Reactivity study of CO+NO reaction over Pd/Al2O3 and Pd/CeZrO2 catalysts. Catal Today 2019. [DOI: 10.1016/j.cattod.2018.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Sun W, Wang Z, Wang Q, Zaman WQ, Cao L, Gong XQ, Yang J. Strategies of alloying effect for regulating Pt-based H 2-SCR catalytic activity. Chem Commun (Camb) 2018; 54:9502-9505. [PMID: 30090883 DOI: 10.1039/c8cc05279d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Alloying Pt with 3d transition metals results in the d-band center moving away from the Fermi level, creating compressive strain. The adsorption strength of the reactants should not be too strong or too weak. The presence of compressive strain, which can increase the orbital overlap between *H and *O, results in the reduction of energy barriers of H-assisted N-O bond activation in terms of the Langmuir-Hinshelwood (L-H) reaction route. Our findings provide guidelines to design more efficient H2-SCR catalysts.
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Affiliation(s)
- Wei Sun
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Processes, School of Resources and Environmental Engineering. East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R. China
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Jian J, Zhang Q, Wu X, Zhou M. Isocyanate Formation from Reactions of Early Lanthanide Metal Atoms with NO and CO in Solid Argon. J Phys Chem A 2017; 121:7861-7868. [PMID: 28972761 DOI: 10.1021/acs.jpca.7b08586] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reactions of early lanthanide metal atoms (Ce, Pr, and Nd) with carbon monoxide and nitric oxide mixtures are studied by infrared absorption spectroscopy in solid argon. The reaction intermediates and products are identified via isotopic substitution as well as theoretical frequency calculations. The results show that the reactions proceed with the initial formation of inserted NLnO molecules, which subsequently react with CO to form the NLnO(CO) complexes on annealing. The NLnO(CO) complexes further isomerize to the more stable isocyanate OLnNCO species under UV light excitation.
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Affiliation(s)
- Jiwen Jian
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , Shanghai 200433, China
| | - Qingnan Zhang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , Shanghai 200433, China
| | - Xuan Wu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , Shanghai 200433, China
| | - Mingfei Zhou
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University , Shanghai 200433, China
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21
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Effect of Calcination Temperature on NO–CO Decomposition by Pd Catalyst Nanoparticles Supported on Alumina Nanofibers. FIBERS 2017. [DOI: 10.3390/fib5020022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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Bai Y, Mavrikakis M. Mechanistic Study of Nitric Oxide Reduction by Hydrogen on Pt(100) (I): A DFT Analysis of the Reaction Network. J Phys Chem B 2017; 122:432-443. [DOI: 10.1021/acs.jpcb.7b01115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yunhai Bai
- Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
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23
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Wang X, Maeda N, Baiker A. Synergistic Effects of Au and FeOx Nanocomposites in Catalytic NO Reduction with CO. ACS Catal 2016. [DOI: 10.1021/acscatal.6b02401] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xianwei Wang
- Key
Laboratory of Industrial Ecology and Environmental Engineering, School
of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People’s Republic of China
| | - Nobutaka Maeda
- Key
Laboratory of Industrial Ecology and Environmental Engineering, School
of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, People’s Republic of China
- Gold
Catalysis Research Center, State Key Laboratory of Catalysis, Dalian
Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan
Road, Dalian 116023, People’s Republic of China
| | - Alfons Baiker
- Institute
for Chemical and Bioengineering, Department of Chemistry and Applied
Biosciences, ETH Zurich, Hönggerberg, HCI, CH-8093 Zurich, Switzerland
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24
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Effect of Surface Copper Species on NO + CO Reaction over xCuO-Ce0.9Zr0.1O2 Catalysts: In Situ DRIFTS Studies. Catalysts 2016. [DOI: 10.3390/catal6080124] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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25
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NO Adsorption and Reaction on Aged Pd–Rh Natural Gas Vehicle Catalysts: A Combined TAP and Steady-State Kinetic Approach. Top Catal 2016. [DOI: 10.1007/s11244-016-0613-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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26
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Nguyen L, Zhang S, Wang L, Li Y, Yoshida H, Patlolla A, Takeda S, Frenkel AI, Tao F(F. Reduction of Nitric Oxide with Hydrogen on Catalysts of Singly Dispersed Bimetallic Sites Pt1Com and Pd1Con. ACS Catal 2016. [DOI: 10.1021/acscatal.5b00842] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luan Nguyen
- Department
of Chemical and Petroleum Engineering and Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Shiran Zhang
- Department
of Chemical and Petroleum Engineering and Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Lei Wang
- Institute
of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuanyuan Li
- Department
of Physics, Yeshiva University, New York, New York 10016, United States
| | - Hideto Yoshida
- Institute
of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
| | - Anitha Patlolla
- Department
of Physics, Yeshiva University, New York, New York 10016, United States
| | - Seiji Takeda
- Institute
of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
| | - Anatoly I. Frenkel
- Department
of Physics, Yeshiva University, New York, New York 10016, United States
| | - Franklin (Feng) Tao
- Department
of Chemical and Petroleum Engineering and Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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27
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Liu N, Chen X, Zhang J, Schwank JW. DRIFTS study of photo-assisted catalytic CO + NO redox reaction over CuO/CeO2-TiO2. Catal Today 2015. [DOI: 10.1016/j.cattod.2015.04.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Wang J, Chen H, Hu Z, Yao M, Li Y. A Review on the Pd-Based Three-Way Catalyst. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING 2014. [DOI: 10.1080/01614940.2014.977059] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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29
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Ferri D, Newton MA, Di Michiel M, Yoon S, Chiarello GL, Marchionni V, Matam SK, Aguirre MH, Weidenkaff A, Wen F, Gieshoff J. Synchrotron high energy X-ray methods coupled to phase sensitive analysis to characterize aging of solid catalysts with enhanced sensitivity. Phys Chem Chem Phys 2013; 15:8629-39. [PMID: 23657925 DOI: 10.1039/c3cp44638g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
X-ray absorption spectroscopy and X-ray diffraction are suitable probes of the chemical state of a catalyst under working conditions but are limited to bulk information. Here we show in two case studies related to hydrothermal aging and chemical modification of model automotive catalysts that enhanced detailed information of structural changes can be obtained when the two methods are combined with a concentration modulated excitation (cME) approach and phase sensitive detection (PSD). The catalysts are subject to a modulation experiment consisting of the periodic variation of the gas feed composition to the catalyst and the time-resolved data are additionally treated by PSD. In the case of a 2 wt% Rh/Al2O3 catalyst, a very small fraction (ca. 2%) of Rh remaining exposed at the alumina surface after hydrothermal aging at 1273 K can be detected by PSD. This Rh is sensitive to the red-ox oscillations of the experiment and is likely responsible for the observed catalytic activity and selectivity during NO reduction by CO. In the case of a 1.6 wt% Pd/Al2O3-Ce(1-x)Zr(x)O2 catalyst, preliminary results of cME-XRD demonstrate that access to the kinetics of the whole material at work can be obtained. Both the red-ox processes involving the oxygen storage support and the Pd component can be followed with great precision. PSD enables the differentiation between Pd deposited on Al2O3 or on Ce(1-x)Zr(x)O2. Modification of the catalyst by phosphorous clearly induces loss of the structural dynamics required for oxygen storage capacity that is provided by the Ce(4+)/Ce(3+) pair. The two case studies demonstrate that detailed kinetics of subtle changes can be uncovered by the combination of in situ X-ray absorption and high energy diffraction methods with PSD.
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Affiliation(s)
- Davide Ferri
- Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
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30
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Wang L, Zhang S, Zhu Y, Patlolla A, Shan J, Yoshida H, Takeda S, Frenkel AI, Tao F(F. Catalysis and In Situ Studies of Rh1/Co3O4 Nanorods in Reduction of NO with H2. ACS Catal 2013. [DOI: 10.1021/cs300816u] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lei Wang
- Department of Chemistry
and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Shiran Zhang
- Department of Chemistry
and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Yuan Zhu
- Department of Chemistry
and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Anitha Patlolla
- Department of Physics, Yeshiva University, New York, New York 10016, United States
| | - Junjun Shan
- Department of Chemistry
and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Hideto Yoshida
- Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
| | - Seiji Takeda
- Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
| | - Anatoly I. Frenkel
- Department of Physics, Yeshiva University, New York, New York 10016, United States
| | - Franklin (Feng) Tao
- Department of Chemistry
and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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31
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Srinivasan A, Depcik C. One-Dimensional Pseudo-Homogeneous Packed-Bed Reactor Modeling: I. Chemical Species Equation and Effective Diffusivity. Chem Eng Technol 2012. [DOI: 10.1002/ceat.201200458] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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33
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Kim JR, Lee KY, Suh MJ, Ihm SK. Ceria–zirconia mixed oxide prepared by continuous hydrothermal synthesis in supercritical water as catalyst support. Catal Today 2012. [DOI: 10.1016/j.cattod.2011.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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34
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Paredis K, Ono LK, Behafarid F, Zhang Z, Yang JC, Frenkel AI, Cuenya BR. Evolution of the structure and chemical state of Pd nanoparticles during the in situ catalytic reduction of NO with H2. J Am Chem Soc 2011; 133:13455-64. [PMID: 21790158 DOI: 10.1021/ja203709t] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An in-depth understanding of the fundamental structure of catalysts during operation is indispensable for tailoring future efficient and selective catalysts. We report the evolution of the structure and oxidation state of ZrO(2)-supported Pd nanocatalysts (∼5 nm) during the in situ reduction of NO with H(2) using X-ray absorption fine-structure spectroscopy and X-ray photoelectron spectroscopy. Prior to the onset of the reaction (≤120 °C), a NO-induced redispersion of our initial metallic Pd nanoparticles over the ZrO(2) support was observed, and Pd(δ+) species were detected. This process parallels the high production of N(2)O observed at the onset of the reaction (>120 °C), while at higher temperatures (≥150 °C) the selectivity shifts mainly toward N(2) (∼80%). Concomitant with the onset of N(2) production, the Pd atoms aggregate again into large (6.5 nm) metallic Pd nanoparticles, which were found to constitute the active phase for the H(2)-reduction of NO. Throughout the entire reaction cycle, the formation and stabilization of PdO(x) was not detected. Our results highlight the importance of in situ reactivity studies to unravel the microscopic processes governing catalytic reactivity.
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Affiliation(s)
- Kristof Paredis
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
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35
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Granger P, Parvulescu VI. Catalytic NOx Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies. Chem Rev 2011; 111:3155-207. [DOI: 10.1021/cr100168g] [Citation(s) in RCA: 573] [Impact Index Per Article: 44.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pascal Granger
- Unité de Catalyse et de Chimie du Solide, UMR CNRS 8181, University of Lille 1, 59655 Villeneuve d’Ascq, France
| | - Vasile I. Parvulescu
- Department of Organic Chemistry, Biochemistry and Catalysis, University of Bucharest, Romania, 4 − 12 Regina Elisabeta Boulevard, Bucharest 030016, Romania
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Srinivasan A, Depcik C. Review of Chemical Reactions in the NO Reduction by CO on Rhodium/Alumina Catalysts. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING 2010. [DOI: 10.1080/01614940.2010.522485] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Anand Srinivasan
- a University of Kansas, Department of Mechanical Engineering , Lawrence , KS , USA
| | - Christopher Depcik
- a University of Kansas, Department of Mechanical Engineering , Lawrence , KS , USA
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37
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Renzas JR, Huang W, Zhang Y, Grass ME, Somorjai GA. Rh1−x Pd x Nanoparticle Composition Dependence in CO Oxidation by NO. Catal Letters 2010. [DOI: 10.1007/s10562-010-0462-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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38
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Pd characterization by XPS in perovskite catalysts for NOx reduction: influence of thermal aging. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3216] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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39
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XPS investigation of surface changes during thermal aging of Natural Gas Vehicle catalysts: Influence of Rh addition to Pd. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3215] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Because of growing environmental concerns and increasingly stringent regulations governing auto emissions, new more efficient exhaust catalysts are needed to reduce the amount of pollutants released from internal combustion engines. To accomplish this goal, the major pollutants in exhaust-CO, NO(x), and unburned hydrocarbons-need to be fully converted to CO(2), N(2), and H(2)O. Most exhaust catalysts contain nanocrystalline noble metals (Pt, Pd, Rh) dispersed on oxide supports such as Al(2)O(3) or SiO(2) promoted by CeO(2). However, in conventional catalysts, only the surface atoms of the noble metal particles serve as adsorption sites, and even in 4-6 nm metal particles, only 1/4 to 1/5 of the total noble metal atoms are utilized for catalytic conversion. The complete dispersion of noble metals can be achieved only as ions within an oxide support. In this Account, we describe a novel solution to this dispersion problem: a new solution combustion method for synthesizing dispersed noble metal ionic catalysts. We have synthesized nanocrystalline, single-phase Ce(1-x)M(x)O(2-delta) and Ce(1-x-y)Ti(y)M(x)O(2-delta) (M = Pt, Pd, Rh; x = 0.01-0.02, delta approximately x, y = 0.15-0.25) oxides in fluorite structure. In these oxide catalysts, Pt(2+), Pd(2+), or Rh(3+) ions are substituted only to the extent of 1-2% of Ce(4+) ion. Lower-valent noble metal ion substitution in CeO(2) creates oxygen vacancies. Reducing molecules (CO, H(2), NH(3)) are adsorbed onto electron-deficient noble metal ions, while oxidizing (O(2), NO) molecules are absorbed onto electron-rich oxide ion vacancy sites. The rates of CO and hydrocarbon oxidation and NO(x) reduction (with >80% N(2) selectivity) are 15-30 times higher in the presence of these ionic catalysts than when the same amount of noble metal loaded on an oxide support is used. Catalysts with palladium ion dispersed in CeO(2) or Ce(1-x)Ti(x)O(2) were far superior to Pt or Rh ionic catalysts. Therefore, we have demonstrated that the more expensive Pt and Rh metals are not necessary in exhaust catalysts. We have also grown these nanocrystalline ionic catalysts on ceramic cordierite and have reproduced the results we observed in powder material on the honeycomb catalytic converter. Oxygen in a CeO(2) lattice is activated by the substitution of Ti ion, as well as noble metal ions. Because this substitution creates longer Ti-O and M-O bonds relative to the average Ce-O bond within the lattice, the materials facilitate high oxygen storage and release. The interaction among M(0)/M(n+), Ce(4+)/Ce(3+), and Ti(4+)/Ti(3+) redox couples leads to the promoting action of CeO(2), activation of lattice oxygen and high oxygen storage capacity, metal support interaction, and high rates of catalytic activity in exhaust catalysis.
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Affiliation(s)
- M. S. Hegde
- Solid State and Structural Chemistry Unit
- Chemical Engineering
- Inorganic and Physical Chemistry
- Indian Institute of Science Bangalore 560012, India
| | - Giridhar Madras
- Solid State and Structural Chemistry Unit
- Chemical Engineering
- Inorganic and Physical Chemistry
- Indian Institute of Science Bangalore 560012, India
| | - K. C. Patil
- Solid State and Structural Chemistry Unit
- Chemical Engineering
- Inorganic and Physical Chemistry
- Indian Institute of Science Bangalore 560012, India
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42
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Characteristics of CeO2–ZrO2 mixed oxide prepared by continuous hydrothermal synthesis in supercritical water as support of Rh catalyst for catalytic reduction of NO by CO. J Catal 2009. [DOI: 10.1016/j.jcat.2009.02.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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