Deciphering the Phillips Catalyst by Orbital Analysis and Supervised Machine Learning from Cr Pre-edge XANES of Molecular Libraries

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-...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Journal of the American Chemical Society 2021-05, Vol.143 (19), p.7326-7341
Hauptverfasser: Trummer, David, Searles, Keith, Algasov, Alexander, Guda, Sergey A, Soldatov, Alexander V, Ramanantoanina, Harry, Safonova, Olga V, Guda, Alexander A, Copéret, Christophe
Format: Artikel
Sprache:eng
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
container_end_page 7341
container_issue 19
container_start_page 7326
container_title Journal of the American Chemical Society
container_volume 143
creator Trummer, David
Searles, Keith
Algasov, Alexander
Guda, Sergey A
Soldatov, Alexander V
Ramanantoanina, Harry
Safonova, Olga V
Guda, Alexander A
Copéret, Christophe
description 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.
doi_str_mv 10.1021/jacs.0c10791
format Article
fullrecord <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_acs_journals_10_1021_jacs_0c10791</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>2526145329</sourcerecordid><originalsourceid>FETCH-LOGICAL-a428t-5ae249ffeaf2a47a6e30341fdf58ea35d996604802204403533ed1d7f85c12bc3</originalsourceid><addsrcrecordid>eNptkMtr20AQh5fQUjtubzmHPfYQpfvU42gc5wFKY3ALvYnRajZeI0vKrhTwuf94JOK2l56GGb75zfARcsHZNWeCf9uDCdfMcJZk_IzMuRYs0lzEH8icMSaiJI3ljJyHsB9bJVL-icykzBKlRDYnv2_QuG6H3jXPtN8h3excXbsu0BX0UB9DT8sjffKlGzu6bKaRCxSaim6HDv2rC1jRRzA71yDNEXwzJVnfHujK043HCKtnpL-W39db2lr62NZohho8zV3pwTsMn8lHC3XAL6e6ID9v1z9W91H-dPewWuYRjG_3kQYUKrMWwQpQCcQomVTcVlanCFJXWRbHTKVMCKYUk1pKrHiV2FQbLkojF-Tre27n25cBQ18cXDBY19BgO4RCaBFzpaXIRvTqHTW-DcGjLTrvDuCPBWfFpL2YtBcn7SN-eUoeygNWf-E_nv-dnrb27eBHkeH_WW8P44uK</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>2526145329</pqid></control><display><type>article</type><title>Deciphering the Phillips Catalyst by Orbital Analysis and Supervised Machine Learning from Cr Pre-edge XANES of Molecular Libraries</title><source>ACS Publications</source><creator>Trummer, David ; Searles, Keith ; Algasov, Alexander ; Guda, Sergey A ; Soldatov, Alexander V ; Ramanantoanina, Harry ; Safonova, Olga V ; Guda, Alexander A ; Copéret, Christophe</creator><creatorcontrib>Trummer, David ; Searles, Keith ; Algasov, Alexander ; Guda, Sergey A ; Soldatov, Alexander V ; Ramanantoanina, Harry ; Safonova, Olga V ; Guda, Alexander A ; Copéret, Christophe</creatorcontrib><description>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.</description><identifier>ISSN: 0002-7863</identifier><identifier>EISSN: 1520-5126</identifier><identifier>DOI: 10.1021/jacs.0c10791</identifier><identifier>PMID: 33974429</identifier><language>eng</language><publisher>United States: American Chemical Society</publisher><ispartof>Journal of the American Chemical Society, 2021-05, Vol.143 (19), p.7326-7341</ispartof><rights>2021 American Chemical Society</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-a428t-5ae249ffeaf2a47a6e30341fdf58ea35d996604802204403533ed1d7f85c12bc3</citedby><cites>FETCH-LOGICAL-a428t-5ae249ffeaf2a47a6e30341fdf58ea35d996604802204403533ed1d7f85c12bc3</cites><orcidid>0000-0002-6772-1414 ; 0000-0002-3222-1604 ; 0000-0002-2086-6958 ; 0000-0002-6941-4987 ; 0000-0001-9660-3890 ; 0000-0002-2398-1847</orcidid></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://pubs.acs.org/doi/pdf/10.1021/jacs.0c10791$$EPDF$$P50$$Gacs$$H</linktopdf><linktohtml>$$Uhttps://pubs.acs.org/doi/10.1021/jacs.0c10791$$EHTML$$P50$$Gacs$$H</linktohtml><link.rule.ids>314,780,784,2765,27076,27924,27925,56738,56788</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/33974429$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Trummer, David</creatorcontrib><creatorcontrib>Searles, Keith</creatorcontrib><creatorcontrib>Algasov, Alexander</creatorcontrib><creatorcontrib>Guda, Sergey A</creatorcontrib><creatorcontrib>Soldatov, Alexander V</creatorcontrib><creatorcontrib>Ramanantoanina, Harry</creatorcontrib><creatorcontrib>Safonova, Olga V</creatorcontrib><creatorcontrib>Guda, Alexander A</creatorcontrib><creatorcontrib>Copéret, Christophe</creatorcontrib><title>Deciphering the Phillips Catalyst by Orbital Analysis and Supervised Machine Learning from Cr Pre-edge XANES of Molecular Libraries</title><title>Journal of the American Chemical Society</title><addtitle>J. Am. Chem. Soc</addtitle><description>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.</description><issn>0002-7863</issn><issn>1520-5126</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2021</creationdate><recordtype>article</recordtype><recordid>eNptkMtr20AQh5fQUjtubzmHPfYQpfvU42gc5wFKY3ALvYnRajZeI0vKrhTwuf94JOK2l56GGb75zfARcsHZNWeCf9uDCdfMcJZk_IzMuRYs0lzEH8icMSaiJI3ljJyHsB9bJVL-icykzBKlRDYnv2_QuG6H3jXPtN8h3excXbsu0BX0UB9DT8sjffKlGzu6bKaRCxSaim6HDv2rC1jRRzA71yDNEXwzJVnfHujK043HCKtnpL-W39db2lr62NZohho8zV3pwTsMn8lHC3XAL6e6ID9v1z9W91H-dPewWuYRjG_3kQYUKrMWwQpQCcQomVTcVlanCFJXWRbHTKVMCKYUk1pKrHiV2FQbLkojF-Tre27n25cBQ18cXDBY19BgO4RCaBFzpaXIRvTqHTW-DcGjLTrvDuCPBWfFpL2YtBcn7SN-eUoeygNWf-E_nv-dnrb27eBHkeH_WW8P44uK</recordid><startdate>20210519</startdate><enddate>20210519</enddate><creator>Trummer, David</creator><creator>Searles, Keith</creator><creator>Algasov, Alexander</creator><creator>Guda, Sergey A</creator><creator>Soldatov, Alexander V</creator><creator>Ramanantoanina, Harry</creator><creator>Safonova, Olga V</creator><creator>Guda, Alexander A</creator><creator>Copéret, Christophe</creator><general>American Chemical Society</general><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7X8</scope><orcidid>https://orcid.org/0000-0002-6772-1414</orcidid><orcidid>https://orcid.org/0000-0002-3222-1604</orcidid><orcidid>https://orcid.org/0000-0002-2086-6958</orcidid><orcidid>https://orcid.org/0000-0002-6941-4987</orcidid><orcidid>https://orcid.org/0000-0001-9660-3890</orcidid><orcidid>https://orcid.org/0000-0002-2398-1847</orcidid></search><sort><creationdate>20210519</creationdate><title>Deciphering the Phillips Catalyst by Orbital Analysis and Supervised Machine Learning from Cr Pre-edge XANES of Molecular Libraries</title><author>Trummer, David ; Searles, Keith ; Algasov, Alexander ; Guda, Sergey A ; Soldatov, Alexander V ; Ramanantoanina, Harry ; Safonova, Olga V ; Guda, Alexander A ; Copéret, Christophe</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-a428t-5ae249ffeaf2a47a6e30341fdf58ea35d996604802204403533ed1d7f85c12bc3</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2021</creationdate><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Trummer, David</creatorcontrib><creatorcontrib>Searles, Keith</creatorcontrib><creatorcontrib>Algasov, Alexander</creatorcontrib><creatorcontrib>Guda, Sergey A</creatorcontrib><creatorcontrib>Soldatov, Alexander V</creatorcontrib><creatorcontrib>Ramanantoanina, Harry</creatorcontrib><creatorcontrib>Safonova, Olga V</creatorcontrib><creatorcontrib>Guda, Alexander A</creatorcontrib><creatorcontrib>Copéret, Christophe</creatorcontrib><collection>PubMed</collection><collection>CrossRef</collection><collection>MEDLINE - Academic</collection><jtitle>Journal of the American Chemical Society</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Trummer, David</au><au>Searles, Keith</au><au>Algasov, Alexander</au><au>Guda, Sergey A</au><au>Soldatov, Alexander V</au><au>Ramanantoanina, Harry</au><au>Safonova, Olga V</au><au>Guda, Alexander A</au><au>Copéret, Christophe</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Deciphering the Phillips Catalyst by Orbital Analysis and Supervised Machine Learning from Cr Pre-edge XANES of Molecular Libraries</atitle><jtitle>Journal of the American Chemical Society</jtitle><addtitle>J. Am. Chem. Soc</addtitle><date>2021-05-19</date><risdate>2021</risdate><volume>143</volume><issue>19</issue><spage>7326</spage><epage>7341</epage><pages>7326-7341</pages><issn>0002-7863</issn><eissn>1520-5126</eissn><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.</abstract><cop>United States</cop><pub>American Chemical Society</pub><pmid>33974429</pmid><doi>10.1021/jacs.0c10791</doi><tpages>16</tpages><orcidid>https://orcid.org/0000-0002-6772-1414</orcidid><orcidid>https://orcid.org/0000-0002-3222-1604</orcidid><orcidid>https://orcid.org/0000-0002-2086-6958</orcidid><orcidid>https://orcid.org/0000-0002-6941-4987</orcidid><orcidid>https://orcid.org/0000-0001-9660-3890</orcidid><orcidid>https://orcid.org/0000-0002-2398-1847</orcidid><oa>free_for_read</oa></addata></record>
fulltext fulltext
identifier ISSN: 0002-7863
ispartof Journal of the American Chemical Society, 2021-05, Vol.143 (19), p.7326-7341
issn 0002-7863
1520-5126
language eng
recordid cdi_acs_journals_10_1021_jacs_0c10791
source ACS Publications
title Deciphering the Phillips Catalyst by Orbital Analysis and Supervised Machine Learning from Cr Pre-edge XANES of Molecular Libraries
url https://sfx.bib-bvb.de/sfx_tum?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-05T23%3A56%3A43IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-proquest_cross&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Deciphering%20the%20Phillips%20Catalyst%20by%20Orbital%20Analysis%20and%20Supervised%20Machine%20Learning%20from%20Cr%20Pre-edge%20XANES%20of%20Molecular%20Libraries&rft.jtitle=Journal%20of%20the%20American%20Chemical%20Society&rft.au=Trummer,%20David&rft.date=2021-05-19&rft.volume=143&rft.issue=19&rft.spage=7326&rft.epage=7341&rft.pages=7326-7341&rft.issn=0002-7863&rft.eissn=1520-5126&rft_id=info:doi/10.1021/jacs.0c10791&rft_dat=%3Cproquest_cross%3E2526145329%3C/proquest_cross%3E%3Curl%3E%3C/url%3E&disable_directlink=true&sfx.directlink=off&sfx.report_link=0&rft_id=info:oai/&rft_pqid=2526145329&rft_id=info:pmid/33974429&rfr_iscdi=true