Cobalt particle size effects in Fischer–Tropsch synthesis: structural and in situ spectroscopic characterisation on reverse micelle-synthesised Co/ITQ-2 model catalysts
CO-FTIR studies in situ and on working Co/ITQ-2 model catalysts suggest a C-driven surface cobalt reconstruction under Fischer–Tropsch synthesis, irrespective of Co particle size. Interfacial metal-support Co δ+ sites are favoured due to nanoparticle flattening, and are proposed as responsible for t...
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| Veröffentlicht in: | Journal of catalysis 2009-08, Vol.266 (1), p.129-144 |
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| creator | Prieto, Gonzalo Martínez, Agustín Concepción, Patricia Moreno-Tost, Ramón |
| description | CO-FTIR studies
in situ and on working Co/ITQ-2 model catalysts suggest a C-driven surface cobalt reconstruction under Fischer–Tropsch synthesis, irrespective of Co particle size. Interfacial metal-support Co
δ+
sites are favoured due to nanoparticle flattening, and are proposed as responsible for the decreased TOF for particles of size |
| doi_str_mv | 10.1016/j.jcat.2009.06.001 |
| format | Article |
| fullrecord | <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_proquest_journals_195448022</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><els_id>S0021951709001869</els_id><sourcerecordid>1817819261</sourcerecordid><originalsourceid>FETCH-LOGICAL-c357t-107e9348dd0f37b130c496852190fe66e608b413f8f2de4e7dda7944c65c97483</originalsourceid><addsrcrecordid>eNp9kc2KFDEUhQtRsB19AVdBcFk1N6nUT8SNNI4ODIjQrkM6uUWnqK6UuamBnpXv4Fv4WD6JaXqYpRC4WXznXM49RfGWQ8WBt9djNVqTKgGgKmgrAP6s2HBQUIpWyefFBkDwUjW8e1m8IhozwJum3xR_tmFvpsQWE5O3EzLyD8hwGNAmYn5mN57sAePfX793MSz5z-g0pwOSpw-MUlxtWqOZmJndGSefVkZLVsdANizeMnsw0diE0ZNJPswsv4j3GAnZ0VucJiyfPNGxbbi-3X0vBTsGhxPLucx0okSvixeDmQjfPM6r4sfN5932a3n37cvt9tNdaeumSyWHDlUte-dgqLs9r8FK1faN4AoGbFtsod9LXg_9IBxK7JwznZLSto1Vnezrq-LdxXeJ4eeKlPQY1jjnlZqrRsoehMiQuEA256SIg16iP5p40hz0uRI96nMl-lyJhlbni2fR-0dnQ9ZMQzSz9fSkFLyvAaDO3McLhznmvceoyXqcLTof82W1C_5_a_4BVtymPg</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>195448022</pqid></control><display><type>article</type><title>Cobalt particle size effects in Fischer–Tropsch synthesis: structural and in situ spectroscopic characterisation on reverse micelle-synthesised Co/ITQ-2 model catalysts</title><source>Access via ScienceDirect (Elsevier)</source><creator>Prieto, Gonzalo ; Martínez, Agustín ; Concepción, Patricia ; Moreno-Tost, Ramón</creator><creatorcontrib>Prieto, Gonzalo ; Martínez, Agustín ; Concepción, Patricia ; Moreno-Tost, Ramón</creatorcontrib><description>CO-FTIR studies
in situ and on working Co/ITQ-2 model catalysts suggest a C-driven surface cobalt reconstruction under Fischer–Tropsch synthesis, irrespective of Co particle size. Interfacial metal-support Co
δ+
sites are favoured due to nanoparticle flattening, and are proposed as responsible for the decreased TOF for particles of size <10
nm.
A series of 10%Co/ITQ-2 model catalysts have been prepared by combining a reverse micellar synthesis with a surface silylated ITQ-2 delaminated zeolite. The catalysts display rather uniform Co
0 particle size distributions in the 5–11
nm range as ascertained by XRD, H
2-chemisorption and (HR)TEM. Additionally, a low dispersed 30%Co/SiO
2 reference sample (
d(Co
0)
=
141
nm) has been prepared by supporting a Co
3O
4 nanopowder on spherical SiO
2. H
2-TPR and DR UV–vis spectroscopy reveal that the preparative approach leads to highly reducible catalysts in the
d(Co
0) range of 5.6–141
nm, while the activation energies for the stepwise Co
3O
4
→
CoO
→
Co
0 reduction are found to be particle size dependent. Formation of barely reducible surface and bulk Co silicate species is observed for samples with
d(Co
3O
4)
⩽
5.9
nm. Under realistic Fischer–Tropsch synthesis conditions (493
K, 2.0
MPa) the TOF increases from 1.2
×
10
−3 to 8.6
×
10
−3
s
−1 when
d(Co
0) is increased from 5.6 to 10.4
nm, and then it remains constant up to a particle size of 141
nm.
In situ and
at work FTIR of adsorbed CO reveal a severe cobalt surface reconstruction towards more open crystal planes and/or defect sites (Co–carbonyl bands in the region of 2000–2025
cm
−1) and suggest adsorbed C adatoms (surface carbidic species), derived from CO dissociation, as the true restructuring agent. Under FTS conditions, this Co surface reconstruction occurs similarly irrespective of the metal particle size. Moreover, an enhancement in the proportion of Co–SiO
2 interfacial Co
δ+
sites (Co–CO band at 2060
cm
−1) takes place particularly in small cobalt nanoparticles (5.6
nm) likely as a consequence of nanoparticle flattening, as suggested by TEM after catalysis. These Co–SiO
2 interfacial sites are tentatively proposed as responsible for the decreased TOF observed for
d(Co
0)
<
10
nm.</description><identifier>ISSN: 0021-9517</identifier><identifier>EISSN: 1090-2694</identifier><identifier>DOI: 10.1016/j.jcat.2009.06.001</identifier><identifier>CODEN: JCTLA5</identifier><language>eng</language><publisher>Amsterdam: Elsevier Inc</publisher><subject>At work CO-FTIR ; Catalysis ; Catalysts ; Chemistry ; Co/ITQ-2 ; Cobalt ; Colloidal state and disperse state ; Exact sciences and technology ; Fischer–Tropsch ; General and physical chemistry ; Ion-exchange ; Metal surface reconstruction ; Micelles. Thin films ; Model catalysts ; Nanoparticles ; Particle size effects ; Physical and chemical studies. Granulometry. Electrokinetic phenomena ; Spectrum analysis ; Surface physical chemistry ; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry ; Zeolites: preparations and properties</subject><ispartof>Journal of catalysis, 2009-08, Vol.266 (1), p.129-144</ispartof><rights>2009 Elsevier Inc.</rights><rights>2009 INIST-CNRS</rights><rights>Copyright © 2009 Elsevier B.V. All rights reserved.</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c357t-107e9348dd0f37b130c496852190fe66e608b413f8f2de4e7dda7944c65c97483</citedby></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktohtml>$$Uhttps://dx.doi.org/10.1016/j.jcat.2009.06.001$$EHTML$$P50$$Gelsevier$$H</linktohtml><link.rule.ids>314,780,784,3550,27924,27925,45995</link.rule.ids><backlink>$$Uhttp://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=21830003$$DView record in Pascal Francis$$Hfree_for_read</backlink></links><search><creatorcontrib>Prieto, Gonzalo</creatorcontrib><creatorcontrib>Martínez, Agustín</creatorcontrib><creatorcontrib>Concepción, Patricia</creatorcontrib><creatorcontrib>Moreno-Tost, Ramón</creatorcontrib><title>Cobalt particle size effects in Fischer–Tropsch synthesis: structural and in situ spectroscopic characterisation on reverse micelle-synthesised Co/ITQ-2 model catalysts</title><title>Journal of catalysis</title><description>CO-FTIR studies
in situ and on working Co/ITQ-2 model catalysts suggest a C-driven surface cobalt reconstruction under Fischer–Tropsch synthesis, irrespective of Co particle size. Interfacial metal-support Co
δ+
sites are favoured due to nanoparticle flattening, and are proposed as responsible for the decreased TOF for particles of size <10
nm.
A series of 10%Co/ITQ-2 model catalysts have been prepared by combining a reverse micellar synthesis with a surface silylated ITQ-2 delaminated zeolite. The catalysts display rather uniform Co
0 particle size distributions in the 5–11
nm range as ascertained by XRD, H
2-chemisorption and (HR)TEM. Additionally, a low dispersed 30%Co/SiO
2 reference sample (
d(Co
0)
=
141
nm) has been prepared by supporting a Co
3O
4 nanopowder on spherical SiO
2. H
2-TPR and DR UV–vis spectroscopy reveal that the preparative approach leads to highly reducible catalysts in the
d(Co
0) range of 5.6–141
nm, while the activation energies for the stepwise Co
3O
4
→
CoO
→
Co
0 reduction are found to be particle size dependent. Formation of barely reducible surface and bulk Co silicate species is observed for samples with
d(Co
3O
4)
⩽
5.9
nm. Under realistic Fischer–Tropsch synthesis conditions (493
K, 2.0
MPa) the TOF increases from 1.2
×
10
−3 to 8.6
×
10
−3
s
−1 when
d(Co
0) is increased from 5.6 to 10.4
nm, and then it remains constant up to a particle size of 141
nm.
In situ and
at work FTIR of adsorbed CO reveal a severe cobalt surface reconstruction towards more open crystal planes and/or defect sites (Co–carbonyl bands in the region of 2000–2025
cm
−1) and suggest adsorbed C adatoms (surface carbidic species), derived from CO dissociation, as the true restructuring agent. Under FTS conditions, this Co surface reconstruction occurs similarly irrespective of the metal particle size. Moreover, an enhancement in the proportion of Co–SiO
2 interfacial Co
δ+
sites (Co–CO band at 2060
cm
−1) takes place particularly in small cobalt nanoparticles (5.6
nm) likely as a consequence of nanoparticle flattening, as suggested by TEM after catalysis. These Co–SiO
2 interfacial sites are tentatively proposed as responsible for the decreased TOF observed for
d(Co
0)
<
10
nm.</description><subject>At work CO-FTIR</subject><subject>Catalysis</subject><subject>Catalysts</subject><subject>Chemistry</subject><subject>Co/ITQ-2</subject><subject>Cobalt</subject><subject>Colloidal state and disperse state</subject><subject>Exact sciences and technology</subject><subject>Fischer–Tropsch</subject><subject>General and physical chemistry</subject><subject>Ion-exchange</subject><subject>Metal surface reconstruction</subject><subject>Micelles. Thin films</subject><subject>Model catalysts</subject><subject>Nanoparticles</subject><subject>Particle size effects</subject><subject>Physical and chemical studies. Granulometry. Electrokinetic phenomena</subject><subject>Spectrum analysis</subject><subject>Surface physical chemistry</subject><subject>Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry</subject><subject>Zeolites: preparations and properties</subject><issn>0021-9517</issn><issn>1090-2694</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2009</creationdate><recordtype>article</recordtype><recordid>eNp9kc2KFDEUhQtRsB19AVdBcFk1N6nUT8SNNI4ODIjQrkM6uUWnqK6UuamBnpXv4Fv4WD6JaXqYpRC4WXznXM49RfGWQ8WBt9djNVqTKgGgKmgrAP6s2HBQUIpWyefFBkDwUjW8e1m8IhozwJum3xR_tmFvpsQWE5O3EzLyD8hwGNAmYn5mN57sAePfX793MSz5z-g0pwOSpw-MUlxtWqOZmJndGSefVkZLVsdANizeMnsw0diE0ZNJPswsv4j3GAnZ0VucJiyfPNGxbbi-3X0vBTsGhxPLucx0okSvixeDmQjfPM6r4sfN5932a3n37cvt9tNdaeumSyWHDlUte-dgqLs9r8FK1faN4AoGbFtsod9LXg_9IBxK7JwznZLSto1Vnezrq-LdxXeJ4eeKlPQY1jjnlZqrRsoehMiQuEA256SIg16iP5p40hz0uRI96nMl-lyJhlbni2fR-0dnQ9ZMQzSz9fSkFLyvAaDO3McLhznmvceoyXqcLTof82W1C_5_a_4BVtymPg</recordid><startdate>20090815</startdate><enddate>20090815</enddate><creator>Prieto, Gonzalo</creator><creator>Martínez, Agustín</creator><creator>Concepción, Patricia</creator><creator>Moreno-Tost, Ramón</creator><general>Elsevier Inc</general><general>Elsevier</general><general>Elsevier BV</general><scope>IQODW</scope><scope>AAYXX</scope><scope>CITATION</scope></search><sort><creationdate>20090815</creationdate><title>Cobalt particle size effects in Fischer–Tropsch synthesis: structural and in situ spectroscopic characterisation on reverse micelle-synthesised Co/ITQ-2 model catalysts</title><author>Prieto, Gonzalo ; Martínez, Agustín ; Concepción, Patricia ; Moreno-Tost, Ramón</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c357t-107e9348dd0f37b130c496852190fe66e608b413f8f2de4e7dda7944c65c97483</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2009</creationdate><topic>At work CO-FTIR</topic><topic>Catalysis</topic><topic>Catalysts</topic><topic>Chemistry</topic><topic>Co/ITQ-2</topic><topic>Cobalt</topic><topic>Colloidal state and disperse state</topic><topic>Exact sciences and technology</topic><topic>Fischer–Tropsch</topic><topic>General and physical chemistry</topic><topic>Ion-exchange</topic><topic>Metal surface reconstruction</topic><topic>Micelles. Thin films</topic><topic>Model catalysts</topic><topic>Nanoparticles</topic><topic>Particle size effects</topic><topic>Physical and chemical studies. Granulometry. Electrokinetic phenomena</topic><topic>Spectrum analysis</topic><topic>Surface physical chemistry</topic><topic>Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry</topic><topic>Zeolites: preparations and properties</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Prieto, Gonzalo</creatorcontrib><creatorcontrib>Martínez, Agustín</creatorcontrib><creatorcontrib>Concepción, Patricia</creatorcontrib><creatorcontrib>Moreno-Tost, Ramón</creatorcontrib><collection>Pascal-Francis</collection><collection>CrossRef</collection><jtitle>Journal of catalysis</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Prieto, Gonzalo</au><au>Martínez, Agustín</au><au>Concepción, Patricia</au><au>Moreno-Tost, Ramón</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Cobalt particle size effects in Fischer–Tropsch synthesis: structural and in situ spectroscopic characterisation on reverse micelle-synthesised Co/ITQ-2 model catalysts</atitle><jtitle>Journal of catalysis</jtitle><date>2009-08-15</date><risdate>2009</risdate><volume>266</volume><issue>1</issue><spage>129</spage><epage>144</epage><pages>129-144</pages><issn>0021-9517</issn><eissn>1090-2694</eissn><coden>JCTLA5</coden><abstract>CO-FTIR studies
in situ and on working Co/ITQ-2 model catalysts suggest a C-driven surface cobalt reconstruction under Fischer–Tropsch synthesis, irrespective of Co particle size. Interfacial metal-support Co
δ+
sites are favoured due to nanoparticle flattening, and are proposed as responsible for the decreased TOF for particles of size <10
nm.
A series of 10%Co/ITQ-2 model catalysts have been prepared by combining a reverse micellar synthesis with a surface silylated ITQ-2 delaminated zeolite. The catalysts display rather uniform Co
0 particle size distributions in the 5–11
nm range as ascertained by XRD, H
2-chemisorption and (HR)TEM. Additionally, a low dispersed 30%Co/SiO
2 reference sample (
d(Co
0)
=
141
nm) has been prepared by supporting a Co
3O
4 nanopowder on spherical SiO
2. H
2-TPR and DR UV–vis spectroscopy reveal that the preparative approach leads to highly reducible catalysts in the
d(Co
0) range of 5.6–141
nm, while the activation energies for the stepwise Co
3O
4
→
CoO
→
Co
0 reduction are found to be particle size dependent. Formation of barely reducible surface and bulk Co silicate species is observed for samples with
d(Co
3O
4)
⩽
5.9
nm. Under realistic Fischer–Tropsch synthesis conditions (493
K, 2.0
MPa) the TOF increases from 1.2
×
10
−3 to 8.6
×
10
−3
s
−1 when
d(Co
0) is increased from 5.6 to 10.4
nm, and then it remains constant up to a particle size of 141
nm.
In situ and
at work FTIR of adsorbed CO reveal a severe cobalt surface reconstruction towards more open crystal planes and/or defect sites (Co–carbonyl bands in the region of 2000–2025
cm
−1) and suggest adsorbed C adatoms (surface carbidic species), derived from CO dissociation, as the true restructuring agent. Under FTS conditions, this Co surface reconstruction occurs similarly irrespective of the metal particle size. Moreover, an enhancement in the proportion of Co–SiO
2 interfacial Co
δ+
sites (Co–CO band at 2060
cm
−1) takes place particularly in small cobalt nanoparticles (5.6
nm) likely as a consequence of nanoparticle flattening, as suggested by TEM after catalysis. These Co–SiO
2 interfacial sites are tentatively proposed as responsible for the decreased TOF observed for
d(Co
0)
<
10
nm.</abstract><cop>Amsterdam</cop><pub>Elsevier Inc</pub><doi>10.1016/j.jcat.2009.06.001</doi><tpages>16</tpages></addata></record> |
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| ispartof | Journal of catalysis, 2009-08, Vol.266 (1), p.129-144 |
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| language | eng |
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| subjects | At work CO-FTIR Catalysis Catalysts Chemistry Co/ITQ-2 Cobalt Colloidal state and disperse state Exact sciences and technology Fischer–Tropsch General and physical chemistry Ion-exchange Metal surface reconstruction Micelles. Thin films Model catalysts Nanoparticles Particle size effects Physical and chemical studies. Granulometry. Electrokinetic phenomena Spectrum analysis Surface physical chemistry Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry Zeolites: preparations and properties |
| title | Cobalt particle size effects in Fischer–Tropsch synthesis: structural and in situ spectroscopic characterisation on reverse micelle-synthesised Co/ITQ-2 model catalysts |
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