Novel aspects of the physical chemistry of Co/SiO2 Fischer–Tropsch catalyst preparations

Puskas, Imre; Fleisch, T. H.; Kaduk, James A.; Marshall, Christopher L.; Meyers, B.L.; Castagnola, Mario; Indacochea, J. E.

doi:10.1016/j.apcata.2006.09.029

Cited by 20 publications

(21 citation statements)

References 28 publications

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“…Figure 2a shows the absorption of silica (1,100, 975, 800 cm -1 ) for the dried catalyst 300Co-1. The spectrum also confirms the absorbance of the nitrate group (1,610, 1,365, 842 cm -1 ) [15] indicating the existence of some cobalt nitrate residue due to low drying temperature. The spinel Co-O bond absorbance peak corresponding to Co 3 O 4 is clearly visible around 667 cm -1 .…”

Section: Ftir-atr Analysissupporting

confidence: 62%

“…Cobalt silicate formation is enhanced by using metal salts decomposing during thermal treatment [13,17] and is a result of a reaction between the aqueous cobalt complexes and silanol groups existing on the silica surface. The calcined sample 300Co-5 (not shown) had a similar spectrum as spectrum (d) but with less cobalt silicate peak intensity which indicates that high drying and calcination temperatures also facilitate cobalt silicate formation due to sintering and silica migration as well [13,15,16]. Surface area supports higher than 560 m 2 /g resulted in strong interaction between the silica surface and the cobalt cations during preparation leading to the formation of more cobalt complexes and undesired cobalt silicate.…”

Section: Ftir-atr Analysismentioning

confidence: 64%

“…Lower support surface area leads to less surface SiOH group formation during preparation and thus less MSI. Puskas et al [15] found using infrared spectroscopy much less than expected Co 3 O 4 formation upon calcination when silica was used as a support. This is also explained by the reaction between CoO and SiO 2 during calcination which prevented large amounts of CoO from further oxidation to form Co 3 O 4 .…”

Section: Ftir-atr Analysismentioning

confidence: 94%

“…Surface area supports higher than 560 m 2 /g resulted in strong interaction between the silica surface and the cobalt cations during preparation leading to the formation of more cobalt complexes and undesired cobalt silicate. Indeed, Puskas et al [15] found that the rate of cobalt silicate formation correlates to the surface area of the silica support.…”

Section: Ftir-atr Analysismentioning

confidence: 98%

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Silica-Supported Cobalt Catalysts for Fischer–Tropsch Synthesis: Effects of Calcination Temperature and Support Surface Area on Cobalt Silicate Formation

2009

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Cobalt silicate formation reduces the activity of the catalyst in Fischer-Tropsch synthesis (FTS). In this article, the effects of calcination temperature and support surface area on the formation of cobalt silicate are explored. FTS catalysts were prepared by incipient wetness impregnation of cobalt nitrate precursor into various silica supports. Deionized water was used as preparation medium. The properties of catalysts were characterized at different stages using FTIR, XRD and BET techniques. FTIR-ATR analysis of the synthesized catalyst samples before and after 48 h reaction identified cobalt species formed during the impregnation/calcination stage and after the reduction/reaction stage. It was found that in the reduction/reaction stage, metal-support interaction (MSI) added to the formation of irreducible cobalt silicate phase. Co/silica catalysts with lower surface area (300 m 2 /g) exhibited higher C 5? selectivity which can be attributed to less MSI and higher reducibility and dispersion. The prepared catalysts with different drying and calcination temperatures were also compared. Catalysts dried and calcined at lower temperatures exhibited higher activity and lower cobalt silicate formation. The catalyst sample calcined at 573 K showed the highest CO conversion and the lowest CH 4 selectivity.

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Section: Ftir-atr Analysissupporting

confidence: 62%

Section: Ftir-atr Analysismentioning

confidence: 64%

Section: Ftir-atr Analysismentioning

confidence: 94%

Section: Ftir-atr Analysismentioning

confidence: 98%

See 2 more Smart Citations

Silica-Supported Cobalt Catalysts for Fischer–Tropsch Synthesis: Effects of Calcination Temperature and Support Surface Area on Cobalt Silicate Formation

2009

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“…Secondly, cobalt oxide produced during decomposition of cobalt precursor can react with the support yielding cobalt- . In addition, Puskas [27] et al suggested that the catalyst structure could be affected by migration of SiO 2 in cobalt silica supported catalysts during cobalt nitrate decomposition and thermal pretreatments.…”

Section: Decomposition Of Cobalt Precursor a Key To Better Cobalt DImentioning

confidence: 99%

Enhancing cobalt dispersion in supported Fischer-Tropsch catalysts via controlled decomposition of cobalt precursors

Khodakov¹

2009

Braz. J. Phys.

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Fischer-Tropsch synthesis is a part of Gas-to Liquids (GTL), Biomass-to-Liquids (BTL) and Coal to Liquids (CTL) technologies, which produce alternatives clean fuels from natural gas, biomass and coal. The catalytic performance of cobalt catalysts in Fischer-Tropsch synthesis strongly depends on the size of cobalt particles in nanoscale range (6-30 nm). Cobalt catalysts are usually prepared via incipient wetness impregnation using cobalt salts (cobalt precursors). Catalyst preparation involves several important steps. The paper shows that decomposition of cobalt precursors is often a crucial step in the catalyst design; slower rate of decomposition of cobalt precursors favors smaller size of cobalt particles, higher cobalt dispersion and enhances catalytic performance in Fischer-Tropsch synthesis.

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Kinetics of Furfural Hydrogenation over Bimetallic Overlayer Catalysts and the Effect of Oxygen Vacancy Concentration on Product Selectivity

et al. 2019

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Furfural hydrogenation over silica‐supported Co@Pd and Cu@Pd bimetallic overlayer catalysts was studied in this work. Both overlayer catalysts showed enhanced reactivity compared to pure Pd in furfural hydrogenation. Langmuir‐Hinshelwood kinetic study revealed that this enhanced reactivity could be attributed to the decreased hydrogen surface coverage on catalyst surface of overlayer catalysts compared to pure Pd during reaction, releasing more available active sites for surface reaction or furfural adsorption to take place. The effect of oxygen vacancy concentration on furfural hydrogenation product selectivity was also studied. It is proposed that oxygen vacancies were crucial for both furfural hydrodeoxygenation and aromatic ring hydrogenation, depending on the concentration of oxygen vacancies. This work provides new perspective for tuning the furfural hydrogenation product selectivity by altering the oxygen vacancy concentration.

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Novel aspects of the physical chemistry of Co/SiO2 Fischer–Tropsch catalyst preparations

Cited by 20 publications

References 28 publications

Silica-Supported Cobalt Catalysts for Fischer–Tropsch Synthesis: Effects of Calcination Temperature and Support Surface Area on Cobalt Silicate Formation

Silica-Supported Cobalt Catalysts for Fischer–Tropsch Synthesis: Effects of Calcination Temperature and Support Surface Area on Cobalt Silicate Formation

Enhancing cobalt dispersion in supported Fischer-Tropsch catalysts via controlled decomposition of cobalt precursors

Kinetics of Furfural Hydrogenation over Bimetallic Overlayer Catalysts and the Effect of Oxygen Vacancy Concentration on Product Selectivity

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