The role of carboxylic acid in cobalt Fischer-Tropsch synthesis catalyst deactivation

Kistamurthy, D.; Saib, A.M.; Moodley, D.J.; Preston, H. S.; Ciobîcă, Ionel M.; Rensburg, Werner Janse van; Niemantsverdriet, J.W.; Weststrate, C.J.

doi:10.1016/j.cattod.2015.11.012

Cited by 16 publications

(18 citation statements)

References 46 publications

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“…[53] This can indicateaprobably transformation of formate speciest om ethanol [94] or to carboxylate species at higher temperatures. PeÇa et al [76] and Kistamurthy et al [97] have observed the presenceo fr esistant carboxylic acids strongly adsorbed on the alumina surface on used Co/Al 2 O 3 FTS catalysts. They suggested that the "fast formates"c ould be intermediates in the formation of methanol, while the "slow formates" remaina dsorbed on the support.…”

Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

“…It has been reported that the iron cations Fe 2 + and Fe 3 + can separately form complexes with carboxylate ligand groups. [97] If significant accumulation of carboxylics pecies also takes place on the neighbouring iron oxide phase, steric hindrance produced for the adsorbed speciesm ay affect the accesso fs yngast ot he iron carbides ites (diffusion limitations) and hence decreasing catalystactivity. These observations support the hypothesis that once the carboxylate species are formed on active sites, they can migrate to the alumina and remain strongly adsorbed, althought hey may also form bonds with Fe 2 + or Fe 3 + in iron oxides( Fe x O y ).…”

Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

“…[39,92] After feeding H 2 diluted with He (10:1) at 280 8Cf or the 15/2 and 15/5 catalysts, the bands associated to formate speciesa t 1395 cm À1 and 1376 cm À1 vanished while the band at 1589 cm À1 showedas light shift to lower wavenumber (1570 cm À1 )a nd the band at 1456 cm À1 corresponding to carboxylic speciesadsorbed on alumina increased in intensity.Paredes et al [53] andL orito et al [93] have reported the presence of two types of formate species with different decomposition rates in H 2 ,w hile the carboxylate speciesa dsorbed on alumina remained unaffected on Co/Al 2 O 3 FTS catalysts. PeÇa et al [76] and Kistamurthy et al [97] have observed the presenceo fr esistant carboxylic acids strongly adsorbed on the alumina surface on used Co/Al 2 O 3 FTS catalysts. Zhang et al [40] reported the www.chemcatchem.org presenceo fc arbonate speciesb etween 1572-1580 cm À1 on a Fe-Cu-based catalyst exposed to air,w hile de Smit et al [98] observed formation of carbonate speciesb yi nsitu XPS during syngas treatment over an iron-based FTS catalyst at atmospheric pressure (1 bar).…”

Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

“…Accumulation of carboxylate species can cause atomicc arbon formation on alumina acidic sites, but do not significantly impact catalyst deactivation. [97] If significant accumulation of carboxylics pecies also takes place on the neighbouring iron oxide phase, steric hindrance produced for the adsorbed speciesm ay affect the accesso fs yngast ot he iron carbides ites (diffusion limitations) and hence decreasing catalystactivity. [3] Conclusions Iron-based catalysts (15 wt %o fF e) supported on alumina promotedwithcopper (0, 0.6, 2, and 5wt% of Cu) werecharacterised in situ at relevant FTS conditions.…”

Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

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The Effect of Copper Loading on Iron Carbide Formation and Surface Species in Iron‐Based Fischer–Tropsch Synthesis Catalysts

et al. 2018

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The effect of copper as promoter on iron carbide formation and the nature of surface species on iron‐based catalyst during Fischer–Tropsch synthesis (FTS) was investigated. Iron‐based catalysts (15 wt % of Fe) supported on alumina promoted with copper (0, 0.6, 2, and 5 wt %) were characterised in situ at relevant FTS conditions. The catalysts promoted with 2 and 5 wt % of Cu showed higher catalytic activity due to the formation of Hägg carbide (Fe5C2) detected by in situ XANES and XRD. The carbide formation is attributed to a weakening of the iron–alumina mixed‐compound interactions, and hence increasing iron reducibility and dispersion. The in situ XANES measurements indicated a maximum carburization degree (ca. 20–22 %) even at high Cu loading. The catalyst promoted with 5 wt % of Cu exhibited higher water‐gas shift activity. Aliphatic hydrocarbons, formate, and carboxylate species were detected on the catalyst surface during FTS. After exposing the spent catalysts to hydrogenation conditions, the carboxylate species remained strongly adsorbed while aliphatic hydrocarbons and formate species disappeared. The accumulation of oxygenates species on the catalyst surface increased with Cu loading. The interaction of oxygenates with alumina and iron oxide particles (FexOy) were revealed, with the latter being a possible reason for inhibition of further iron carburization.

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Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

Section: Ex Situ Tem Characterisation:fresh and Used Catalystmentioning

confidence: 99%

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The Effect of Copper Loading on Iron Carbide Formation and Surface Species in Iron‐Based Fischer–Tropsch Synthesis Catalysts

et al. 2018

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“…Oxygenates showed special affinity to the acid sites of the support [35,36]. Moreover, it has been reported that carboxylic acids can cause atomic carbon formation on cobalt-based catalysts during FTS as a result of strongly adsorbed carboxylate species on the support [37]. In addition, once adsorbed, they can accumulate on catalyst surface and generate steric hindrance [36], probably leading to a decay in catalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Identification of carbon species on iron-based catalysts during Fischer-Tropsch synthesis

Peña

Cognigni

Neumayer

et al. 2018

Applied Catalysis A: General

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This paper focuses on the use of in situ and ex situ characterisation techniques to provide evidences of carbon species on a commercial iron-based Fischer-Tropsch synthesis catalyst as well as other indices of potential deactivation mechanisms. In situ XANES measurements demonstrate that re-oxidation or transformation of the active iron phase, i.e. the Hägg carbide phase, was not a significant deactivation mechanism at the studied conditions. Sintering of Hägg carbide nanoparticles is significant with increasing temperatures and time on stream. The sintering mechanism is proposed to be a hydrothermally-assisted process. In situ DRIFTS indicates the presence of different carbon species on the catalyst surface such as aliphatic hydrocarbons from wax products and oxygenate compounds such as alcohols, aldehydes/ketones and carboxylate species. Carboxylate species are resistant towards hydrogenation at 280°C. The presence of different carbon species on the surface after wax product extraction is evident from TPH-MS measurements. GC-MS analysis shows that the strongly adsorbed carbon species remaining on the catalyst surface from wax products are mainly α-olefins and branched carboxylic species. The interaction of oxygenate compounds, especially carboxylate species with iron oxide, may form stable complexes limiting further iron catalyst carburization. STEM-EDX analysis shows that carbon is preferentially located on iron particles.

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Facile Synthesis of Iron Carbide via Pyrolysis of Ferrous Fumarate for Catalytic CO₂ Hydrogenation to Lower Olefins

Qi,

Si,

et al. 2024

ChemSusChem

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Hydrogenation of CO2 to olefin catalyzed by iron‐based catalysts is a sustainable and important way to achieve carbon neutrality. In this study, iron‐based catalysts were facilely prepared by direct pyrolysis of ferric fumarate (FF), which are applied to CO2 hydrogenation to olefin reaction to explore the effects of pyrolysis temperature and atmosphere on catalytic performance of the catalysts. Among them, NaFe‐Air‐400 catalyst exhibits the highest catalytic activity with 33.7%, and light olefin selectivity reaches as high as 47.1%. The catalytic performance of pyrolytic catalysts is better than that the impregnated NaFe catalyst on activated carbon (NaFe/AC). A series of XRD, Raman and SEM characterization results show a suitable pyrolysis temperature would promote the balance between amorphous carbon and graphene, which can affect the formation of FexCy phase, leading the distinctive activity and olefin selectivity. Hence, the presented one‐step pyrolysis methodology would provide a facile and quick synthesis of highly‐active iron‐based catalyst design for CO2 conversion.

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The role of carboxylic acid in cobalt Fischer-Tropsch synthesis catalyst deactivation

Cited by 16 publications

References 46 publications

The Effect of Copper Loading on Iron Carbide Formation and Surface Species in Iron‐Based Fischer–Tropsch Synthesis Catalysts

The Effect of Copper Loading on Iron Carbide Formation and Surface Species in Iron‐Based Fischer–Tropsch Synthesis Catalysts

Identification of carbon species on iron-based catalysts during Fischer-Tropsch synthesis

Facile Synthesis of Iron Carbide via Pyrolysis of Ferrous Fumarate for Catalytic CO₂ Hydrogenation to Lower Olefins

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The role of carboxylic acid in cobalt Fischer-Tropsch synthesis catalyst deactivation

Cited by 16 publications

References 46 publications

The Effect of Copper Loading on Iron Carbide Formation and Surface Species in Iron‐Based Fischer–Tropsch Synthesis Catalysts

The Effect of Copper Loading on Iron Carbide Formation and Surface Species in Iron‐Based Fischer–Tropsch Synthesis Catalysts

Identification of carbon species on iron-based catalysts during Fischer-Tropsch synthesis

Facile Synthesis of Iron Carbide via Pyrolysis of Ferrous Fumarate for Catalytic CO2 Hydrogenation to Lower Olefins

Contact Info

Product

Resources

About

Facile Synthesis of Iron Carbide via Pyrolysis of Ferrous Fumarate for Catalytic CO₂ Hydrogenation to Lower Olefins