Copper ferrites: A model for investigating the role of copper in the dynamic iron-based Fischer–Tropsch catalyst

Chonco, Zandile Hlengiwe; Lodya, Lonzeche; Claeys, Michael; Steen, Eric van

doi:10.1016/j.jcat.2013.08.012

Cited by 52 publications

(47 citation statements)

References 59 publications

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“…Fischer-Tropsch catalysts are typically activated prior to their exposure to synthesis gas in hydrogen, carbon monoxide, or synthesis gas [1,13,46]. The activation of the model compounds in hydrogen or carbon monoxide was followed using in situ XRD.…”

Section: Resultsmentioning

confidence: 99%

“…Thermodynamically, the conversion of large magnetite crystallites to iron carbide under the reported conditions is favored [22]. The conversion of magnetite to iron carbide during the Fischer-Tropsch synthesis is assisted by the presence reduction promoter copper [13], which might be a consequence of hydrogen spillover from the copper to the magnetite phase. The partially reduced magnetite phase might be carburized more easily under Fischer-Tropsch conditions, thus enhancing the activity of promoted iron-based catalyst.…”

Section: Introductionmentioning

confidence: 89%

“…The functioning of copper as a reduction promoter requires the close proximity of copper to the iron phase [6]. Recently, we explored the role of copper using spinel copper ferrite as a model compound [13]. It was deduced that copper is capable of hydrogen spillover during H 2 -activation.…”

Section: Introductionmentioning

confidence: 99%

“…A high catalytic activity is maintained by increasing the fraction of iron present as iron carbide in the catalyst [17][18][19][20]. Typically, the iron catalysts contain large magnetite crystallites in addition to small iron carbide crystallites [13,21]. Thermodynamically, the conversion of large magnetite crystallites to iron carbide under the reported conditions is favored [22].…”

Section: Introductionmentioning

confidence: 99%

“…The partially reduced magnetite phase might be carburized more easily under Fischer-Tropsch conditions, thus enhancing the activity of promoted iron-based catalyst. The enhanced rate of carburization would be associated with an increased CO 2 -selectivity [13,23].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Comparing silver and copper as promoters in Fe-based Fischer–Tropsch catalysts using delafossite as a model compound

Chonco¹,

Ferreira²,

Lodya³

et al. 2013

Journal of Catalysis

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Comparing silver and copper as promoters in Fe-based Fischer–Tropsch catalysts using delafossite as a model compound

Chonco¹,

Ferreira²,

Lodya³

et al. 2013

Journal of Catalysis

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Crucial Role of Self‐Exsolved Heterostructured Cermet Nanoparticles in Highly Active Spinel Electrodes for CO₂/H₂O Co‐Electrolysis

Wu,

Matsuda,

Staykov

et al. 2023

Advanced Energy Materials

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The versatility of the spinel (AB2O4) oxides means they are of great interest for a variety of catalysis and energy conversion applications, involving gas reactions and reforming. CuFe2O4 spinel is identified as a highly efficient fuel electrode for CO2/H2O co‐electrolysis due to its promising electrocatalytic activity. To identify the actual active sites, the electrochemical characteristics, composition, chemical state, and microstructure are systematically investigated while optimizing the electrolysis performance by varying the feed gas composition. Markedly enhanced electrolysis current density is achieved under a CO2‐enriched composition of 50%CO2/10%H2O‐Ar. This promising performance is attributed to the in situ exsolution of heterostructural “Cu/Fe3O4” nanoparticles on the parent CuFe2O4 surface during co‐electrolysis. Interestingly, a strong correlation of the electrolysis performance with the amount of the formed heterostructural cermet is observed. The exsolved cermet heterostructure plays a crucial role in CO2/H2O electroreduction, as also confirmed by density‐functional‐theory studies. The self‐exsolved Cu/Fe3O4 nanoparticles present exceptional strength due to a strong interaction between the formed metallic Cu and Fe3O4, enabling the electrode to remain active and stable under such high electrical polarization. The excellent durability and stability of the self‐exsolved heterostructural nanoparticles are clearly confirmed by long‐term operation at high‐working voltage with an outstanding Faradaic efficiency (nearly 100%).

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Probing The Structure Evolution of Iron‐Based Fischer–Tropsch to Produce Olefins by Operando Raman Spectroscopy

Dai

et al. 2015

ChemCatChem

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By using operando Raman spectroscopy (ORS), we investigated the panoramic structure evolution of an iron oxide (a-Fe 2 O 3 ) catalyst, which is used for the production of olefins via Fischer-Tropsch (FTO). During activation in different atmospheres and reaction at 260 8C and 3.0 MPa, a-Fe 2 O 3 was only partially transformed into g-Fe 2 O 3 by H 2 pretreatment; meanwhile, a transformation of a-Fe 2 O 3 !g-Fe 2 O 3 !Fe 3 O 4 !Fe 5 C 2 was observed in both CO and syngas (H 2 /CO). Combining with other techniques such as XRD, TEM, XPS and TPSR, we reveal that assembles of various iron oxides (g-Fe 2 O 3 , Fe 3 O 4 , Fe carbide, and their combinations) are responsible for FTO. Especially, the preliminary relationship of catalyst structure and performance relating to the production of olefins directly from syngas was established. Such a study is critical for further understanding of the FTO reaction and other catalytic reactions.The iron-based Fischer-Tropsch synthesis (FTS) is a key platform for synthesizing liquid fuels or other value-added chemicals. [1][2][3] The structure evolution of iron catalysts for FTS has been studied by both academia and industry for almost 100 years. [4] It is well known that several phases (iron carbides, metallic iron, and magnetite) are produced during the reaction, and all of them have been suggested to be active for FTS. [5] On the other hand, the complexity of "real world" catalysts often precludes a detailed knowledge of the evolution of their microscopic structures and a related reaction mechanism because of the limitation of instruments.Owing to the development of surface-sensitive techniques and high-performance computers in last decades, the "operando" techniques [6][7][8][9] for the simultaneous determination of the dynamic structure of working catalysts in FTS and the catalytic performance has been developed. [10][11][12][13] A great effort (see the Supporting Information, Table S1) has been contributed to the study of the iron-based FTS using in situ or operando techniques, such as XAS, [10,14,15] IR, [16] MES, [12] XRD, [17][18][19][20] XPS [21] and STXM, [22] Raman, [23] and so on. Up to date, to the best of our knowledge, the structure evolution of iron oxide catalysts op-erating under industrial conditions (high pressure, high temperature) is rarely reported. [24] Operando Raman spectroscopy (ORS) has proven to be a powerful approach by operating over a broad temperature range 25-1000 8C and pressure range 0.1-10.0 MPa. It is even sensitive to a tiny modification of the structure that results from heat-and/or reaction-induced roughening on catalysts, while the Raman signal is less affected by the presence of H 2 O and other gases. [25][26][27] However, most of the hitherto successful applications of this technique are concentrated on several relative simple or moderate (e.g., ambient pressure) reactions, such as propane ammoxidation, [28] propane oxidative dehydrogenation, [29,30] and CO oxidation. [31] For complex reactions under harsh conditions such as FTS, ORS has be...

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Copper ferrites: A model for investigating the role of copper in the dynamic iron-based Fischer–Tropsch catalyst

Cited by 52 publications

References 59 publications

Comparing silver and copper as promoters in Fe-based Fischer–Tropsch catalysts using delafossite as a model compound

Comparing silver and copper as promoters in Fe-based Fischer–Tropsch catalysts using delafossite as a model compound

Crucial Role of Self‐Exsolved Heterostructured Cermet Nanoparticles in Highly Active Spinel Electrodes for CO₂/H₂O Co‐Electrolysis

Probing The Structure Evolution of Iron‐Based Fischer–Tropsch to Produce Olefins by Operando Raman Spectroscopy

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Copper ferrites: A model for investigating the role of copper in the dynamic iron-based Fischer–Tropsch catalyst

Cited by 52 publications

References 59 publications

Comparing silver and copper as promoters in Fe-based Fischer–Tropsch catalysts using delafossite as a model compound

Comparing silver and copper as promoters in Fe-based Fischer–Tropsch catalysts using delafossite as a model compound

Crucial Role of Self‐Exsolved Heterostructured Cermet Nanoparticles in Highly Active Spinel Electrodes for CO2/H2O Co‐Electrolysis

Probing The Structure Evolution of Iron‐Based Fischer–Tropsch to Produce Olefins by Operando Raman Spectroscopy

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Resources

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Crucial Role of Self‐Exsolved Heterostructured Cermet Nanoparticles in Highly Active Spinel Electrodes for CO₂/H₂O Co‐Electrolysis