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Nifant'ev I, Komarov P, Sadrtdinova G, Safronov V, Kolosov N, Ivchenko P. Mechanistic Insights of Ethylene Polymerization on Phillips Chromium Catalysts. Polymers (Basel) 2024; 16:681. [PMID: 38475365 DOI: 10.3390/polym16050681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024] Open
Abstract
Silica-supported chromium oxide catalysts, also named Phillips chromium catalysts (PCCs), provide more than half of the world's production of high- and medium-density polyethylenes. PCCs are usually prepared in the Cr(VI)/SiO2 form, which is subjected to reductive activation. It has been explicitly proven that CO reduces Cr(VI) to Cr(II) species that initiate ethylene polymerization; ethylene activates Cr(VI) sites as well, but the nature of the catalytic species is complicated by the presence of the ethylene oxidation products. It is widely accepted that the catalytic species are of a Cr(III)-alkyl nature, but this common assumption faces the challenge of "extra" hydrogen: the formation of similar species under the action of even-electron reducing agents requires an additional H atom. Relatively recently, it was found that saturated hydrocarbons can also activate CrOx/SiO2, and alkyl fragments turn out to be bonded with a polyethylene chain. In recent years, there have been numerous experimental and theoretical studies of the structure and chemistry of PCCs at the different stages of preparation and activation. The use of modern spectral methods (such as extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES), and others); operando IR, UV-vis, EPR, and XAS spectroscopies; and theoretical approaches (DFT modeling, machine learning) clarified many essential aspects of the mechanisms of CrOx/SiO2 activation and catalytic behavior. Overall, the Cosse-Arlman mechanism of polymerization on Cr(III)-alkyl centers is confirmed in many works, but its theoretical support required the development of nontrivial and contentious mechanistic concepts of Cr(VI)/SiO2 or Cr(II)/SiO2 activation. On the other hand, conflicting experimental data continue to be obtained, and certain mechanistic concepts are being developed with the use of outdated models. Strictly speaking, the main question of what type of catalytic species, Cr(II), Cr(III), or Cr(IV), comes into polymerization still has not received an unambiguous answer. The role of the chemical nature of the support-through the prism of the nature, geometry, and distribution of the active sites-is also not clear in depth. In the present review, we endeavored to summarize and discuss the recent studies in the field of the preparation, activation, and action of PCCs, with a focus on existing contradictions in the interpretation of the experimental and theoretical results.
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Affiliation(s)
- Ilya Nifant'ev
- A.V. Topchiev Institute of Petrochemical Synthesis RAS, 29 Leninsky Pr., 119991 Moscow, Russia
- Department of Chemistry, M.V. Lomonosov Moscow University, 1-3 Leninskie Gory, 119991 Moscow, Russia
| | - Pavel Komarov
- A.V. Topchiev Institute of Petrochemical Synthesis RAS, 29 Leninsky Pr., 119991 Moscow, Russia
| | - Guzelia Sadrtdinova
- A.V. Topchiev Institute of Petrochemical Synthesis RAS, 29 Leninsky Pr., 119991 Moscow, Russia
- Faculty of Chemistry, National Research University Higher School of Economics, Myasnitskaya St. 20, 101100 Moscow, Russia
| | | | | | - Pavel Ivchenko
- A.V. Topchiev Institute of Petrochemical Synthesis RAS, 29 Leninsky Pr., 119991 Moscow, Russia
- Department of Chemistry, M.V. Lomonosov Moscow University, 1-3 Leninskie Gory, 119991 Moscow, Russia
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Ashuiev A, Giorgia Nobile A, Trummer D, Klose D, Guda S, Safonova OV, Copéret C, Guda A, Jeschke G. Active Sites in Cr(III)-Based Ethylene Polymerization Catalysts from Machine-Learning-Supported XAS and EPR Spectroscopy. Angew Chem Int Ed Engl 2024; 63:e202313348. [PMID: 37970660 DOI: 10.1002/anie.202313348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/13/2023] [Accepted: 11/16/2023] [Indexed: 11/17/2023]
Abstract
The ethylene polymerization Phillips catalyst has been employed for decades and is central to the polymer industry. While Cr(III) alkyl species are proposed to be the propagating sites, there is so far no direct experimental evidence for such proposal. In this work, by coupling Surface organometallic chemistry, EPR spectroscopy, and machine learning-supported XAS studies, we have studied the electronic structure of well-defined silica-supported Cr(III) alkyls and identified the presence of several surface species in high and low-spin states, associated with different coordination environments. Notably, low-spin Cr(III) sites are shown to participate in ethylene polymerization, indicating that similar Cr(III) alkyl species could be involved in the related Phillips catalyst.
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Affiliation(s)
- Anton Ashuiev
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Anna Giorgia Nobile
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - David Trummer
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Daniel Klose
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Sergey Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, 344090, Russia
| | - Olga V Safonova
- Paul Scherrer Institut, WLGA/217, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
| | - Alexander Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, 344090, Russia
| | - Gunnar Jeschke
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1-5, 8093, Zürich, Switzerland
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3
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Groppo E, Rojas-Buzo S, Bordiga S. The Role of In Situ/ Operando IR Spectroscopy in Unraveling Adsorbate-Induced Structural Changes in Heterogeneous Catalysis. Chem Rev 2023; 123:12135-12169. [PMID: 37882638 PMCID: PMC10636737 DOI: 10.1021/acs.chemrev.3c00372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Indexed: 10/27/2023]
Abstract
Heterogeneous catalysts undergo thermal- and/or adsorbate-induced dynamic changes under reaction conditions, which consequently modify their catalytic behavior. Hence, it is increasingly crucial to characterize the properties of a catalyst under reaction conditions through the so-called "operando" approach. Operando IR spectroscopy is probably one of the most ubiquitous and versatile characterization methods in the field of heterogeneous catalysis, but its potential in identifying adsorbate- and thermal-induced phenomena is often overlooked in favor of other less accessible methods, such as XAS spectroscopy and high-resolution microscopy. Without detracting from these techniques, and while aware of the enormous value of a multitechnique approach, the purpose of this Review is to show that IR spectroscopy alone can provide relevant information in this field. This is done by discussing a few selected case studies from our own research experience, which belong to the categories of both "single-site"- and nanoparticle-based catalysts.
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Affiliation(s)
- Elena Groppo
- Department of Chemistry,
NIS Centre and INSTM, University of Torino, via Giuria 7, 10125 Turin, Italy
| | - Sergio Rojas-Buzo
- Department of Chemistry,
NIS Centre and INSTM, University of Torino, via Giuria 7, 10125 Turin, Italy
| | - Silvia Bordiga
- Department of Chemistry,
NIS Centre and INSTM, University of Torino, via Giuria 7, 10125 Turin, Italy
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4
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Hydroperoxyl-mediated C-H bond activation on Cr single atom catalyst: An alternative to the Fenton mechanism. J Catal 2023. [DOI: 10.1016/j.jcat.2022.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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5
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Alzamly A, Bakiro M, Hussein Ahmed S, Siddig LA, Nguyen HL. Linear α-olefin oligomerization and polymerization catalyzed by metal-organic frameworks. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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6
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Wang J, Zhu ML, Song YH, Liu ZT, Wang L, Liu ZW. Molecular-level investigation on supported CrOx catalyst for oxidative dehydrogenation of propane with carbon dioxide. J Catal 2022. [DOI: 10.1016/j.jcat.2022.03.027] [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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7
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Huang C, Liu Z, Liu B, Terano M, Jin Y. Computational Insights into the Multisite Nature of the Phillips CrO x/SiO 2 Catalyst for Ethylene Polymerization: The Perspective of Chromasiloxane Ring Size and F Modification. ACS Catal 2022. [DOI: 10.1021/acscatal.1c04998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Cuimin Huang
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou 510630, People’s Republic of China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510630, People’s Republic of China
| | - Zhen Liu
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
| | - Boping Liu
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou 510630, People’s Republic of China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510630, People’s Republic of China
| | - Minoru Terano
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Yulong Jin
- Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou 510630, People’s Republic of China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510630, People’s Republic of China
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8
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Wang D, Zhou S, Liu Y, Kang X, Liu S, Li Z, Braunstein P. Controlling Polyethylene Molecular Weights and Distributions Using Chromium Complexes Supported by SNN-Tridentate Ligands. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02351] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dongqi Wang
- Key Laboratory of Biobased Polymer Materials, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Shengmei Zhou
- Key Laboratory of Biobased Polymer Materials, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Yongxin Liu
- Key Laboratory of Biobased Polymer Materials, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Xiaohui Kang
- College of Pharmacy, Dalian Medical University, Dalian 116044, China
| | - Shaofeng Liu
- Key Laboratory of Biobased Polymer Materials, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Zhibo Li
- Key Laboratory of Biobased Polymer Materials, College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Pierre Braunstein
- Laboratoire de Chimie de Coordination, CNRS, CHIMIE UMR 7177, Université de Strasbourg, 4 rue Blaise Pascal, 67081 Cedex Strasbourg, France
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Tian J, Zhang X, Liu S, Li Z. Chromium Complexes Supported by NNO-Tridentate Ligands: An Unprecedent Activity with the Low Requirement of MAO. Polym Chem 2022. [DOI: 10.1039/d2py00125j] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of metal catalysts with high activity and thermal stability but low requirement of MAO as cocatalyst is highly desired for polyolefin industrial application. In this contribution, a series...
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10
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Piovano A, Groppo E. Flexible ligands in heterogeneous catalysts for olefin polymerization: Insights from spectroscopy. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214258] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Goetjen TA, Knapp JG, Syed ZH, Hackler RA, Zhang X, Delferro M, Hupp JT, Farha OK. Ethylene polymerization with a crystallographically well-defined metal–organic framework supported catalyst. Catal Sci Technol 2022. [DOI: 10.1039/d1cy01990b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Crystallographic characterization of a heterogeneous ethylene polymerization catalyst elucidates a chromium–carbon bond after alkyl aluminum activation and provides mechanistic insights.
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Affiliation(s)
- Timothy A. Goetjen
- Department of Chemistry and International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA 60208
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, USA 60439
| | - Julia G. Knapp
- Department of Chemistry and International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA 60208
| | - Zoha H. Syed
- Department of Chemistry and International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA 60208
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, USA 60439
| | - Ryan A. Hackler
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, USA 60439
| | - Xuan Zhang
- Department of Chemistry and International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA 60208
| | - Massimiliano Delferro
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL, USA 60439
| | - Joseph T. Hupp
- Department of Chemistry and International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA 60208
| | - Omar K. Farha
- Department of Chemistry and International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA 60208
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, USA 60208
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12
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Werny MJ, Zarupski J, ten Have IC, Piovano A, Hendriksen C, Friederichs NH, Meirer F, Groppo E, Weckhuysen BM. Correlating the Morphological Evolution of Individual Catalyst Particles to the Kinetic Behavior of Metallocene-Based Ethylene Polymerization Catalysts. JACS AU 2021; 1:1996-2008. [PMID: 35574041 PMCID: PMC8611720 DOI: 10.1021/jacsau.1c00324] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Indexed: 06/12/2023]
Abstract
Kinetics-based differences in the early stage fragmentation of two structurally analogous silica-supported hafnocene- and zirconocene-based catalysts were observed during gas-phase ethylene polymerization at low pressures. A combination of focused ion beam-scanning electron microscopy (FIB-SEM) and nanoscale infrared photoinduced force microscopy (IR PiFM) revealed notable differences in the distribution of the support, polymer, and composite phases between the two catalyst materials. By means of time-resolved probe molecule infrared spectroscopy, correlations between this divergence in morphology and the kinetic behavior of the catalysts' active sites were established. The rate of polymer formation, a property that is inherently related to a catalyst's kinetics and the applied reaction conditions, ultimately governs mass transfer and thus the degree of homogeneity achieved during support fragmentation. In the absence of strong mass transfer limitations, a layer-by-layer mechanism dominates at the level of the individual catalyst support domains under the given experimental conditions.
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Affiliation(s)
- Maximilian J. Werny
- Inorganic
Chemistry and Catalysis group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Jelena Zarupski
- Department
of Chemistry, INSTM and NIS Centre, University
of Torino, Via G. Quarello
15A, 10135 Torino, Italy
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Iris C. ten Have
- Inorganic
Chemistry and Catalysis group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Alessandro Piovano
- Department
of Chemistry, INSTM and NIS Centre, University
of Torino, Via G. Quarello
15A, 10135 Torino, Italy
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Coen Hendriksen
- SABIC
Technology Center, Urmonderbaan 22, 6167 RD Geleen, The Netherlands
| | | | - Florian Meirer
- Inorganic
Chemistry and Catalysis group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Elena Groppo
- Department
of Chemistry, INSTM and NIS Centre, University
of Torino, Via G. Quarello
15A, 10135 Torino, Italy
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Bert M. Weckhuysen
- Inorganic
Chemistry and Catalysis group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
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Lazzarini A, Colaiezzi R, Gabriele F, Crucianelli M. Support-Activity Relationship in Heterogeneous Catalysis for Biomass Valorization and Fine-Chemicals Production. MATERIALS 2021; 14:ma14226796. [PMID: 34832198 PMCID: PMC8619138 DOI: 10.3390/ma14226796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022]
Abstract
Heterogeneous catalysts are progressively expanding their field of application, from high-throughput reactions for traditional industrial chemistry with production volumes reaching millions of tons per year, a sector in which they are key players, to more niche applications for the production of fine chemicals. These novel applications require a progressive utilization reduction of fossil feedstocks, in favor of renewable ones. Biomasses are the most accessible source of organic precursors, having as advantage their low cost and even distribution across the globe. Unfortunately, they are intrinsically inhomogeneous in nature and their efficient exploitation requires novel catalysts. In this process, an accurate design of the active phase performing the reaction is important; nevertheless, we are often neglecting the importance of the support in guaranteeing stable performances and improving catalytic activity. This review has the goal of gathering and highlighting the cases in which the supports (either derived or not from biomass wastes) share the worth of performing the catalysis with the active phase, for those reactions involving the synthesis of fine chemicals starting from biomasses as feedstocks.
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14
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Vummaleti SVC, Genest A, Rösch N. Ethene Conversion at a Zeolite‐Supported Ir(I) Complex. A Computational Perspective on a Single‐Site Catalyst System. ChemCatChem 2021. [DOI: 10.1002/cctc.202100615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sai V. C. Vummaleti
- Institute of High Performance Computing Agency for Science Technology and Research 1 Fusionopolis Way, #16-6 Connexis Singapore 138632 Singapore
| | - Alexander Genest
- Institute of High Performance Computing Agency for Science Technology and Research 1 Fusionopolis Way, #16-6 Connexis Singapore 138632 Singapore
- Institute of Materials Chemistry Technische Universität Wien Getreidemarkt 9/BC A-1060 Vienna Austria
| | - Notker Rösch
- Institute of Materials Chemistry Technische Universität Wien Getreidemarkt 9/BC A-1060 Vienna Austria
- Department Chemie and Catalysis Research Center Technische Universität München Lichtenbergstr. 4 85747 Garching Germany
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15
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Abstract
Both metallocene and Phillips chromium catalysts are used in the commercial manufacture of polyethylene. Unlike most other commercial metallocene systems, the Chevron Phillips Chemical (CPC) platform does not use methylaluminoxane or fluoroorganic boranes. Instead, the support itself serves to activate (ionize) the metallocenes, which then polymerize ethylene at high activity. Most of these solid acid supports can also be used to anchor Cr to make a Phillips catalyst. This provides an interesting opportunity to compare the polymerization responses by these two disparate systems, Phillips Cr and CPC metallocene, when supported on the same solid acid carriers. In this study, both chromium oxide and several metallocenes were deposited onto a variety of solid oxides, under a variety of conditions, and the resulting support effects were observed and compared. Although using seemingly different chemistries, the two catalyst systems exhibited a surprising number of similarities, which can be attributed to the acidity and porosity of these diverse supports.
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Trummer D, Searles K, Algasov A, Guda SA, Soldatov AV, Ramanantoanina H, Safonova OV, Guda AA, Copéret C. Deciphering the Phillips Catalyst by Orbital Analysis and Supervised Machine Learning from Cr Pre-edge XANES of Molecular Libraries. J Am Chem Soc 2021; 143:7326-7341. [PMID: 33974429 DOI: 10.1021/jacs.0c10791] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Unveiling the nature and the distribution of surface sites in heterogeneous catalysts, and for the Phillips catalyst (CrO3/SiO2) in particular, is still a grand challenge despite more than 60 years of research. Commonly used references in Cr K-edge XANES spectral analysis rely on bulk materials (Cr-foil, Cr2O3) or molecules (CrCl3) that significantly differ from actual surface sites. In this work, we built a library of Cr K-edge XANES spectra for a series of tailored molecular Cr complexes, varying in oxidation state, local coordination environment, and ligand strength. Quantitative analysis of the pre-edge region revealed the origin of the pre-edge shape and intensity distribution. In particular, the characteristic pre-edge splitting observed for Cr(III) and Cr(IV) molecular complexes is directly related to the electronic exchange interactions in the frontier orbitals (spin-up and -down transitions). The series of experimental references was extended by theoretical spectra for potential active site structures and used for training the Extra Trees machine learning algorithm. The most informative features of the spectra (descriptors) were selected for the prediction of Cr oxidation states, mean interatomic distances in the first coordination sphere, and type of ligands. This set of descriptors was applied to uncover the site distribution in the Phillips catalyst at three different stages of the process. The freshly calcined catalyst consists of mainly Cr(VI) sites. The CO-exposed catalyst contains mainly Cr(II) silicates with a minor fraction of Cr(III) sites. The Phillips catalyst exposed to ethylene contains mainly highly coordinated Cr(III) silicates along with unreduced Cr(VI) sites.
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Affiliation(s)
- David Trummer
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Keith Searles
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Alexander Algasov
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, Russia, 344090.,Institute of Mathematics, Mechanics and Computer Science, Southern Federal University, Milchakova 8a, Rostov-on-Don, Russia, 344090
| | - Sergey A Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, Russia, 344090.,Institute of Mathematics, Mechanics and Computer Science, Southern Federal University, Milchakova 8a, Rostov-on-Don, Russia, 344090
| | - Alexander V Soldatov
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, Russia, 344090
| | | | | | - Alexander A Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, Rostov-on-Don, Russia, 344090
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
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De S, Ould-Chikh S, Aguilar A, Hazemann JL, Zitolo A, Ramirez A, Telalovic S, Gascon J. Stable Cr-MFI Catalysts for the Nonoxidative Dehydrogenation of Ethane: Catalytic Performance and Nature of the Active Sites. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05170] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Sudipta De
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Samy Ould-Chikh
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Antonio Aguilar
- Institut Neel, UPR 2940 CNRS − Université Grenoble Alpes, F-38000 Grenoble, France
| | - Jean-Louis Hazemann
- Institut Neel, UPR 2940 CNRS − Université Grenoble Alpes, F-38000 Grenoble, France
| | - Andrea Zitolo
- Synchrotron SOLEIL, L’orme des Merisiers, BP 48 Saint Aubin, 91192 Gif-sur-Yvette, France
| | - Adrian Ramirez
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Selvedin Telalovic
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Jorge Gascon
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
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18
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Monwar M, Cruz C, Barr J, McDaniel M. Ethylene polymerization by hydrocarbon-reduced Cr/silica catalyst. J Catal 2021. [DOI: 10.1016/j.jcat.2020.10.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Cr[CH(SiMe3)2]3/SiO2 catalysts for ethene polymerization: The correlation at a molecular level between the chromium loading and the microstructure of the produced polymer. J Catal 2021. [DOI: 10.1016/j.jcat.2020.12.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Zanchin G, Piovano A, Amodio A, De Stefano F, Di Girolamo R, Groppo E, Leone G. NEt 3-Triggered Synthesis of UHMWPE Using Chromium Complexes Bearing Non-innocent Iminopyridine Ligands. Macromolecules 2021. [DOI: 10.1021/acs.macromol.0c02475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giorgia Zanchin
- CNR, Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” (SCITEC), via A. Corti 12, I-20133 Milano, Italy
| | - Alessandro Piovano
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Alessia Amodio
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Fabio De Stefano
- Dipartimento di Scienze Chimiche, Università di Napoli “Federico II”, Complesso Monte S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Rocco Di Girolamo
- Dipartimento di Scienze Chimiche, Università di Napoli “Federico II”, Complesso Monte S. Angelo, via Cintia, I-80126 Napoli, Italy
| | - Elena Groppo
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Giuseppe Leone
- CNR, Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” (SCITEC), via A. Corti 12, I-20133 Milano, Italy
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21
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Jongkind MK, Meirer F, Bossers KW, ten Have IC, Ohldag H, Watts B, van Kessel T, Friederichs N, Weckhuysen BM. Influence of Metal-Alkyls on Early-Stage Ethylene Polymerization over a Cr/SiO 2 Phillips Catalyst: A Bulk Characterization and X-ray Chemical Imaging Study. Chemistry 2021; 27:1688-1699. [PMID: 32729972 PMCID: PMC7898848 DOI: 10.1002/chem.202002632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/22/2020] [Indexed: 12/03/2022]
Abstract
The Cr/SiO2 Phillips catalyst has taken a central role in ethylene polymerization since its invention in 1953. The uniqueness of this catalyst is related to its ability to produce broad molecular weight distribution (MWD) PE materials as well as that no co-catalysts are required to attain activity. Nonetheless, co-catalysts in the form of metal-alkyls can be added for scavenging poisons, enhancing catalyst activity, reducing the induction period, and tailoring polymer characteristics. The activation mechanism and related polymerization mechanism remain elusive, despite extensive industrial and academic research. Here, we show that by varying the type and amount of metal-alkyl co-catalyst, we can tailor polymer properties around a single Cr/SiO2 Phillips catalyst formulation. Furthermore, we show that these different polymer properties exist in the early stages of polymerization. We have used conventional polymer characterization techniques, such as size exclusion chromatography (SEC) and 13 C NMR, for studying the metal-alkyl co-catalyst effect on short-chain branching (SCB), long-chain branching (LCB) and molecular weight distribution (MWD) at the bulk scale. In addition, scanning transmission X-ray microscopy (STXM) was used as a synchrotron technique to study the PE formation in the early stages: allowing us to investigate the produced type of early-stage PE within one particle cross-section with high energy resolution and nanometer scale spatial resolution.
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Affiliation(s)
- Maarten K. Jongkind
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Florian Meirer
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Koen W. Bossers
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Iris C. ten Have
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Hendrik Ohldag
- Advanced Light Source, MicroscopyLawrence Berkeley National Laboratory1 Cyclotron RoadBerkeleyCA94720USA
- Department of Materials Science and EngineeringStanford University450 Serra MallStanfordCA943505USA
- Department of PhysicsUniversity of California Santa Cruz1156 High StreetSanta CruzCA95064USA
| | - Benjamin Watts
- Laboratory for Synchotron Radiation—Condensed Matter (LSC)Paul Scherrer Institute (PSI)Forschungsstrasse 1115232VilligenSwitzerland
| | - Theo van Kessel
- Technology and Innovation DepartmentSABICUrmonderbaan 226167 RDGeleenThe Netherlands
| | - Nic. Friederichs
- Technology and Innovation DepartmentSABICUrmonderbaan 226167 RDGeleenThe Netherlands
| | - Bert M. Weckhuysen
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
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22
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Vandervelden CA, Khan SA, Peters B. Importance learning estimator for the site-averaged turnover frequency of a disordered solid catalyst. J Chem Phys 2020; 153:244120. [PMID: 33380094 DOI: 10.1063/5.0037450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
For disordered catalysts such as atomically dispersed "single-atom" metals on amorphous silica, the active sites inherit different properties from their quenched-disordered local environments. The observed kinetics are site-averages, typically dominated by a small fraction of highly active sites. Standard sampling methods require expensive ab initio calculations at an intractable number of sites to converge on the site-averaged kinetics. We present a new method that efficiently estimates the site-averaged turnover frequency (TOF). The new estimator uses the same importance learning algorithm [Vandervelden et al., React. Chem. Eng. 5, 77 (2020)] that we previously used to compute the site-averaged activation energy. We demonstrate the method by computing the site-averaged TOF for a simple disordered lattice model of an amorphous catalyst. The results show that with the importance learning algorithm, the site-averaged TOF and activation energy can now be obtained concurrently with orders of magnitude reduction in required ab initio calculations.
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Affiliation(s)
- Craig A Vandervelden
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Salman A Khan
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - Baron Peters
- Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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23
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Wang S, Liu B, Jin Y. Why could the CrOx/SiO2 and VOx/SiO2 catalysts show so different behaviors in ethylene polymerization? A theoretical approach. MOLECULAR CATALYSIS 2020. [DOI: 10.1016/j.mcat.2020.111090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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Tielens F, Gierada M, Handzlik J, Calatayud M. Characterization of amorphous silica based catalysts using DFT computational methods. Catal Today 2020. [DOI: 10.1016/j.cattod.2019.03.062] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Jongkind MK, van Kessel T, Velthoen MEZ, Friederichs N, Weckhuysen BM. Tuning the Redox Chemistry of a Cr/SiO 2 Phillips Catalyst for Controlling Activity, Induction Period and Polymer Properties. Chemphyschem 2020; 21:1665-1674. [PMID: 32539171 PMCID: PMC7496818 DOI: 10.1002/cphc.202000488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 06/12/2020] [Indexed: 11/06/2022]
Abstract
The Cr/SiO2 Phillips catalyst has taken a central role in ethylene polymerization ever since its discovery in 1953. This catalyst is unique compared to other ethylene polymerization catalysts, since it is active without the addition of a metal-alkyl co-catalyst. However, metal-alkyls can be added for scavenging poisons, enhancing the catalyst activity, reducing the induction period and altering polymer characteristics. Despite extensive research into the working state of the catalyst, still no consensus has been reached. Here, we show that by varying the type of metal-alkyl co-catalyst and its amount, the Cr redox chemistry can be tailored, resulting in distinct catalyst activities, induction periods, and polymer characteristics. We have used in-situ UV-Vis-NIR diffuse reflectance spectroscopy (DRS) for studying the Cr oxidation state during the reduction by tri-ethyl borane (TEB) or tri-ethyl aluminum (TEAl) and during subsequent ethylene polymerization. The results show that TEB primarily acts as a reductant and reduces Cr6+ with subsequent ethylene polymerization resulting in rapid polyethylene formation. TEAl generated two types of Cr2+ sites, inaccessible Cr3+ sites and active Cr4+ sites. Subsequent addition of ethylene also revealed an increased reducibility of residual Cr6+ sites and resulted in rapid polyethylene formation. Our results demonstrate the possibility of controlling the reduction chemistry by adding the proper amount and type of metal-alkyl for obtaining desired catalyst activities and tailored polyethylene characteristics.
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Affiliation(s)
- Maarten K. Jongkind
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Theo van Kessel
- SABICTechnology and Innovation DepartmentUrmonderbaan 226167RD GeleenThe Netherlands
| | - Marjolein E. Z. Velthoen
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
| | - Nic. Friederichs
- SABICTechnology and Innovation DepartmentUrmonderbaan 226167RD GeleenThe Netherlands
| | - Bert M. Weckhuysen
- Inorganic Chemistry and CatalysisDebye Institute for Nanomaterial ScienceUtrecht UniversityUniversiteitsweg 993584 CGUtrechtThe Netherlands
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26
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Piovano A, Zarupski J, Groppo E. Disclosing the Interaction between Carbon Monoxide and Alkylated Ti 3+ Species: a Direct Insight into Ziegler-Natta Catalysis. J Phys Chem Lett 2020; 11:5632-5637. [PMID: 32584046 PMCID: PMC8008442 DOI: 10.1021/acs.jpclett.0c01665] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
In the field of Ziegler-Natta catalysis for olefin polymerization, carbon monoxide (CO) is used in the industrial practice to quench the reaction when it proceeds too fast, approaching critical levels for the plant safety. The quenching effect is explained as due to the reversible coordination of CO to the titanium active sites, but no direct evidence has been ever reported. In this work, we designed a series of experiments to monitor CO adsorption at variable temperatures on a model Ziegler-Natta catalyst by means of FT-IR spectroscopy. For the first time, we have been able to spectroscopically detect CO coordinated to alkylated Ti3+ sites and the Ti-acyl species formed upon the subsequent insertion of CO into the Ti3+-alkyl bond, both in the absence and in the presence of the olefin monomer. In perspective, this has important implications for the characterization of the active sites in industrial Ziegler-Natta catalysts, even under working conditions.
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27
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Liu Y, Zhang R, Ren H, Liu Y, Ling S, Zhang H, Liu B, Cheng R. CrV Bimetallic Phillips Catalyst Prepared by Citric Acid‐Assisted Impregnation on Ethylene Polymerization. MACROMOL CHEM PHYS 2020. [DOI: 10.1002/macp.202000010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ying Liu
- State Key Laboratory of Chemical EngineeringEast China University of Science and Technology Meilong Road 130 Shanghai 200237 P. R. China
| | - Rui Zhang
- Daqing Petrochemical Research CenterCNPC NO. 2 Chengxiang Road Daqing Heilongjiang 163000 P. R. China
| | - He Ren
- Daqing Petrochemical Research CenterCNPC NO. 2 Chengxiang Road Daqing Heilongjiang 163000 P. R. China
| | - Yue Liu
- State Key Laboratory of Chemical EngineeringEast China University of Science and Technology Meilong Road 130 Shanghai 200237 P. R. China
| | - Shijia Ling
- State Key Laboratory of Chemical EngineeringEast China University of Science and Technology Meilong Road 130 Shanghai 200237 P. R. China
| | - Hongwei Zhang
- State Key Laboratory of Chemical EngineeringEast China University of Science and Technology Meilong Road 130 Shanghai 200237 P. R. China
| | - Boping Liu
- College of Materials and EnergySouth China Agricultural University Wushan Road 483 Guangzhou 510642 P. R. China
| | - Ruihua Cheng
- State Key Laboratory of Chemical EngineeringEast China University of Science and Technology Meilong Road 130 Shanghai 200237 P. R. China
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28
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Martino GA, Piovano A, Barzan C, Rabeah J, Agostini G, Bruekner A, Leone G, Zanchin G, Monoi T, Groppo E. Rationalizing the Effect of Triethylaluminum on the Cr/SiO 2 Phillips Catalysts. ACS Catal 2020. [DOI: 10.1021/acscatal.9b04726] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giorgia A. Martino
- Department of Chemistry, NIS Centre and INSTM, University of Torino, via G. Quarello 15A, 10135 Torino, Italy
| | - Alessandro Piovano
- Department of Chemistry, NIS Centre and INSTM, University of Torino, via G. Quarello 15A, 10135 Torino, Italy
| | - Caterina Barzan
- Department of Chemistry, NIS Centre and INSTM, University of Torino, via G. Quarello 15A, 10135 Torino, Italy
| | - Jabor Rabeah
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT), Albert-Einstein-Str. 29, D-18059 Rostock, Germany
| | - Giovanni Agostini
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT), Albert-Einstein-Str. 29, D-18059 Rostock, Germany
| | - Angelika Bruekner
- Leibniz Institute for Catalysis at the University of Rostock (LIKAT), Albert-Einstein-Str. 29, D-18059 Rostock, Germany
| | - Giuseppe Leone
- CNR, Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” (SCITEC), via A. corti 12, I-20133 Milano, Italy
| | - Giorgia Zanchin
- CNR, Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” (SCITEC), via A. corti 12, I-20133 Milano, Italy
| | - Takashi Monoi
- R&D Division, Japan Polychem Corporation, 1-1 Marunouchi 1-chome, Chiyoda-ku, 100-8251 Tokyo, Japan
| | - Elena Groppo
- Department of Chemistry, NIS Centre and INSTM, University of Torino, via G. Quarello 15A, 10135 Torino, Italy
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29
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Grauke R, Schepper R, Rabeah J, Schoch R, Bentrup U, Bauer M, Brückner A. Impact of Al Activators on Structure and Catalytic Performance of Cr Catalysts in Homogeneous Ethylene Oligomerization – A Multitechnique
in situ/operando
Study. ChemCatChem 2019. [DOI: 10.1002/cctc.201901441] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Reni Grauke
- Leibniz-Institut für Katalyse e. V. an derUniversität Rostock (LIKAT) Albert-Einstein-Str. 29a Rostock 18059 Germany
| | - Rahel Schepper
- Department Chemie and Center for Sustainable Systems Design (CSSD)Universität Paderborn Warburger Straße 100 Paderborn D-33098 Germany
| | - Jabor Rabeah
- Leibniz-Institut für Katalyse e. V. an derUniversität Rostock (LIKAT) Albert-Einstein-Str. 29a Rostock 18059 Germany
| | - Roland Schoch
- Department Chemie and Center for Sustainable Systems Design (CSSD)Universität Paderborn Warburger Straße 100 Paderborn D-33098 Germany
| | - Ursula Bentrup
- Leibniz-Institut für Katalyse e. V. an derUniversität Rostock (LIKAT) Albert-Einstein-Str. 29a Rostock 18059 Germany
| | - Matthias Bauer
- Department Chemie and Center for Sustainable Systems Design (CSSD)Universität Paderborn Warburger Straße 100 Paderborn D-33098 Germany
| | - Angelika Brückner
- Leibniz-Institut für Katalyse e. V. an derUniversität Rostock (LIKAT) Albert-Einstein-Str. 29a Rostock 18059 Germany
- Department Life, Light & Matter Faculty for Interdisciplinary ResearchUniversity of Rostock Albert-Einstein-Straße 25 Rostock 18059 Germany
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30
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Wang C, Li A, Li C, Zhang S, Li H, Zhou X, Hu L, Feng Y, Wang K, Zhu Z, Shao R, Chen Y, Gao P, Mao S, Huang J, Zhang Z, Han X. Ultrahigh Photocatalytic Rate at a Single-Metal-Atom-Oxide. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1903491. [PMID: 31725182 DOI: 10.1002/adma.201903491] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 09/21/2019] [Indexed: 06/10/2023]
Abstract
Metal oxides, as one of the mostly abundant and widely utilized materials, are extensively investigated and applied in environmental remediation and protection, and in energy conversion and storage. Most of these diverse applications are the result of a large diversity of the electronic states of metal oxides. Noticeably, however, many metal oxides present obstacles for applications in catalysis, mainly due to the lack of efficient active sites with desired electronic states. Here, the fabrication of single-tungsten-atom-oxide (STAO) is demonstrated, in which the metal oxide's volume reaches its minimum as a unit cell. The catalytic mechanism in the STAO is determined by a new single-site physics mechanism, named as quasi-atom physics. The photogenerated electron transfer process is enabled by an electron in the spin-up channel excited from the highest occupied molecular orbital to the lowest unoccupied molecular orbital +1 state, which can only occur in STAO with W5+ . STAO results in a record-high and stable sunlight photocatalytic degradation rate of 0.24 s-1 , which exceeds the rates of available photocatalysts by two orders of magnitude. The fabrication of STAO and its unique quasi-atom photocatalytic mechanism lays new ground for achieving novel physical and chemical properties using single-metal-atom oxides (SMAO).
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Affiliation(s)
- Cong Wang
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Ang Li
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Chong Li
- International Laboratory for Quantum Functional Materials of Henan, School of Physics and Engineering, Zhengzhou University, Zhengzhou, 450001, China
| | - Shengbai Zhang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Hui Li
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Xiaoyuan Zhou
- College of Physics, Institute of Advanced Interdisciplinary Studies, Chongqing University, Chongqing, 401331, China
| | - Liming Hu
- Department of Biological and Chemical Engineering, Beijing University of Technology, Beijing, 100124, China
| | - Yibo Feng
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Kaiwen Wang
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Zhu Zhu
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Ruiwen Shao
- Electron Microscopy Laboratory, International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Yanhui Chen
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Peng Gao
- Electron Microscopy Laboratory, International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Shengcheng Mao
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
| | - Jun Huang
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
- School of Chemical and Biomolecular Engineering, Sydney Nano Institute, The University of Sydney Nano Institute, Sydney, New South Wales, 2006, Australia
| | - Ze Zhang
- Department of Material Science, Zhejiang University, Hangzhou, 310008, China
| | - Xiaodong Han
- Institute of Microstructure and Property of Advanced Materials, Beijing Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing, 100124, China
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31
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Deactivation study of zirconocene immobilization into Lewis acid and dual-shell silicas prepared by a nonhydrolytic sol-gel method. J Catal 2019. [DOI: 10.1016/j.jcat.2019.08.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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32
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33
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Copéret C. Single-Sites and Nanoparticles at Tailored Interfaces Prepared via Surface Organometallic Chemistry from Thermolytic Molecular Precursors. Acc Chem Res 2019; 52:1697-1708. [PMID: 31150207 DOI: 10.1021/acs.accounts.9b00138] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Heterogeneous catalysts are complex by nature, making particularly difficult to assess the structure of their active sites. Such complexity is inherited in part from their mode of preparation, which typically involves coprecipitation or impregnation of metal salts in aqueous solution, and the associated complex surface chemistries. In this context, surface organometallic chemistry (SOMC) has emerged as a powerful approach to generate well-defined surface species, where the metal sites are introduced by grafting tailored molecular precursors. When combined with thermolytic molecular precursors (TMPs) that can lose their organic moieties quite readily upon thermal treatment, SOMC provides access to supported isolated metal sites with defined oxidation state and nuclearity inherited from the precursor. The resulting surface species bear unusual coordination imposed by the surface that provides them high reactivity in comparison with their molecular precursor. In addition, these molecularly defined species bare strong resemblance with the active sites of supported metal oxides. However, they typically contain a higher proportion of active sites making structure-activity relationship possible. They thus constitute ideal models for this important class of industrial catalysts that are used in numerous applications such as olefin epoxidation (Shell process), olefin metathesis (triolefin process), ethylene polymerization (Phillips catalysts), or propane dehydrogenation (Catofin and related processes). This SOMC/TMP approach can thus provide detailed information about the structure of active sites in industrial catalysts, their mode of initiation and deactivation, as well as the role of the support and specific thermal treatment on the final activity of the catalysts. Nonetheless, these structurally characterized surface sites still exhibit heterogeneous environments borrowed from the support itself, that explain the intrinsic complexity of heterogeneous catalysis. Furthermore, SOMC/TMP can also be used to generate and investigate supported metal nanoparticles. Starting from the well-defined isolated sites, that also contain adjacent surface OH groups, one can graft a second metal and then generate after treatment under hydrogen small and narrowly dispersed alloys or nanoparticles with tailored interfaces that can show improved catalytic performances and are amiable to detailed structure-activity relationships. This approach is illustrated by two case studies: (1) formation of supported copper nanoparticles at tailored interfaces that contain isolated metal sites for the selective hydrogenation of carbon dioxide to methanol, allowing for a detailed understanding of the role of dopants and supports in heterogeneous catalysis, and (2) preparation of highly selective and productive propane dehydrogenation catalysts based on silica-supported Pt xGa y alloy. Overall, this Account shows how the combination of SOMC and TMP helps to generate catalysts, particularly suited for elucidating structural characterization of active sites at a molecular-level which in turn enables structure-activity relationship to be drawn. Such detailed information obtained on well-defined catalysts can then be used to understand complex effects observed in industrial catalysts (effects of supports, additives, dopants, etc.), and to extract information that can then be used to improve them in a more rational way.
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Affiliation(s)
- Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg. 1-5, CH-8093 Zürich, Switzerland
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34
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Barzan C, Piovano A, Botavina M, Martino GA, Agostini G, Martra G, Groppo E. Exploring the benefits beyond the pre-reduction in methane of the Cr/SiO2 Phillips catalyst: The molecular structure of the Cr sites and their role in the catalytic performance. J Catal 2019. [DOI: 10.1016/j.jcat.2019.03.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Leone G, Groppo E, Zanchin G, Martino GA, Piovano A, Bertini F, Martí-Rujas J, Parisini E, Ricci G. Concerted Electron Transfer in Iminopyridine Chromium Complexes: Ligand Effects on the Polymerization of Various (Di)olefins. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00812] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giuseppe Leone
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
| | - Elena Groppo
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Giorgia Zanchin
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
| | - Giorgia A. Martino
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Alessandro Piovano
- Dipartimento di Chimica, NIS Interdepartmental Research Center and INSTM Reference Center, Università degli Studi di Torino, Via G. Quarello 15A, I-10135 Torino, Italy
| | - Fabio Bertini
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
| | - Javier Martí-Rujas
- Center for Nano Science and Technology at Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, I-20133 Milano, Italy
| | - Emilio Parisini
- Center for Nano Science and Technology at Polimi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, I-20133 Milano, Italy
| | - Giovanni Ricci
- CNR-Istituto per lo Studio delle Macromolecole (ISMAC), via A. Corti 12, I-20133 Milano, Italy
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