Structural characterization of cobalt catalysts on a silica support

Srinivasan, Ram; Angelis, R.J. De; Reucroft, P. J.; Dhere, A.G.; Bentley, J.

doi:10.1016/0021-9517(89)90082-1

Cited by 51 publications

(16 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In nanometre scale particles both fcc and hcp forms may coexist [14,15], possibly leading to an influence of the resulting stacking faults on the catalytic activity. For example, as underlined by S. Kala et al [16], the presence of many stacking faults in nanoparticles results in large amounts of hydrogen incorporation.…”

Section: Introductionmentioning

confidence: 99%

Microstructure of Supported Cobalt Fischer-Tropsch Catalysts

Ducreux

Rebours

Lynch

et al. 2008

Oil & Gas Science and Technology - Rev. IFP

146

130

View full text Add to dashboard Cite

Résumé -Microstructure de catalyseurs Fischer-Tropsch à base de cobalt supporté -La structure de particules métalliques de cobalt supporté sur silice ou sur alumine, et en présence ou non d'un promoteur (Ru), a été étudiée in situ par diffraction des rayons X conventionnelle et anomale. Par comparaison avec des diagrammes simulés, il est montré que cette structure est caractérisée par la présence de défauts d'empilement dont la densité est directement reliée à la température de réduction du cobalt. Des traitements de carburation/décarburation sous CO et H 2 nous ont permis de modifier de manière contrôlée la microstructure du cobalt métallique pour un même support tout en limitant la variation de la taille des particules. Quel que soit le support, et en présence ou non d'un promoteur, les basses températures de réduction favorisent la formation de la forme hexagonale compacte du cobalt, alors qu'une réduction à haute température favorisera la forme cubique faces centrées. Dans les conditions de la synthèse Fischer-Tropsch, les catalyseurs contenant du cobalt à forte densité d'empilements de type hexagonal compact montrent une activité en conversion du CO nettement supérieure à celle des catalyseurs majoritairement cubiques. Abstract -Microstructure of Supported Cobalt Fischer-Tropsch Catalysts -The structures of metallic cobalt particles supported on silica (with and without Ru promoter) and on alumina have been investigated in-situ by conventional and anomalous X-ray diffraction.Comparison with simulated XRD patterns shows the structure to consist of a defect phase characterised by the presence of stacking faults, the density of which is directly related to the temperature at which the cobalt oxide is reduced.

show abstract

Section: Introductionmentioning

confidence: 99%

Microstructure of Supported Cobalt Fischer-Tropsch Catalysts

Ducreux

Rebours

Lynch

et al. 2008

Oil & Gas Science and Technology - Rev. IFP

146

130

View full text Add to dashboard Cite

show abstract

“…Various Pd 3 Co 1 /Ce x C catalysts were designated as Ce x . Moreover, it has been demonstrated that the reduction temperature of Co ions and formation temperature of PdÀCo alloy was located at 570-620 K, [38] therefore, the Ce 15 sample was reduced at 620 K for the sake of comparison and the sample was XRD: The phase structure of the synthesized samples was characterized with a Shimadzu XRD using Cu Ka radiation operated at 40 kV and 25 mA. Besides, the mean particle size of the alloy catalysts was determined by way of Scherrer's equation.…”

Section: Methodsmentioning

confidence: 99%

“…Various Pd 3 Co 1 /Ce x C catalysts were designated as Ce x . Moreover, it has been demonstrated that the reduction temperature of Co ions and formation temperature of PdÀCo alloy was located at 570-620 K, [38] therefore, the Ce 15 sample was reduced at 620 K for the sake of comparison and the sample was named as Ce 15 -620. Carbon supported 20 wt % of Pd (Pd/C) or Ce (Ce/C) was also prepared by the same method for the comparison.…”

Section: Methodsmentioning

confidence: 99%

“…The PdCo/ Ce x C (x = 0-20) catalysts will be prepared via the depositionprecipitation (DP) method at pH 11 and subsequently reduced at a low temperature of 390 K under H 2 atmosphere. Generally, a temperature higher than 620 K is needed to fully reduce the Co ions, oxides or hydroxides, [38] however, it has also been reported that by use of PdCl 2 as catalysts, Co ions can be successfully reduced at 420 K. [39] Low-temperature processes for the chemical reduction preparation and/or thermal treatments offer many advantages. For example, sintering or grain growth of the NPs can be inhibited and catalysts with a small size and high dispersion can be prepared.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Surface Species Alteration and Oxygen Reduction Reaction Enhancement of PdCo/C Electrocatalysts Induced by Ceria Modification

2010

View full text Add to dashboard Cite

The effect of reduction temperature and CeO2 addition on the activity of PdCo/C alloy catalysts (see scheme) toward the oxygen reduction reaction (ORR) is investigated. By combining X‐ray analysis and temperature‐programmed reduction with electrochemical measurements, the relationship between phase structure, surface information and catalytic activity toward ORR of the non‐Pt PdCo catalysts is elucidated.

show abstract

“…In catalytic oxidation, the most important factor is the selection of the catalysts [4]. Catalyst precursor [5][6][7][8], support [9][10][11], preparation method [12][13][14][15][16] and metal loading [17] have also been observed to influence the oxidation behaviour of catalysts [18].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Ag–M (M: Fe, Co and Mn)–ZSM‐5 bimetal catalysts with high performance for catalytic oxidation of ethyl acetate

Jodaei

Salari

Niaei

et al. 2011

Environmental Technology

View full text Add to dashboard Cite

The catalytic combustion of ethyl acetate has been investigated in a series of mono-metal silver and bimetal Ag-M (M: Fe, Co and Mn)-modified HZSM-5 zeolites. The objective was to find a catalyst with high superior activity, selectivity towards deep oxidation product and stability. The catalyst activity was measured under excess oxygen condition in a fixed bed reactor operated at gas hourly space velocity (GHSV) = 30000 h(-1), reaction temperature between 150 and 450 degrees C and ethyl acetate inlet concentration of 1000 ppm. Both Fe-Ag-ZSM-5 and Co-Ag-ZSM-5 catalysts exhibited high activity in the oxidation of ethyl acetate. The sequences of catalytic activity and catalytic stability were as follows: Fe-Ag-ZSM-5 > Co-Ag-ZSM-5 > Mn-Ag-ZSM-5 > Ag-ZSM-5 > HZSM-5. Total conversion of ethyl acetate was achieved at above 250 degrees C. The catalysts were characterized by inductively coupled plasma atomic emission spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy.

show abstract

Structural characterization of cobalt catalysts on a silica support

Cited by 51 publications

References 6 publications

Microstructure of Supported Cobalt Fischer-Tropsch Catalysts

Microstructure of Supported Cobalt Fischer-Tropsch Catalysts

Surface Species Alteration and Oxygen Reduction Reaction Enhancement of PdCo/C Electrocatalysts Induced by Ceria Modification

Preparation of Ag–M (M: Fe, Co and Mn)–ZSM‐5 bimetal catalysts with high performance for catalytic oxidation of ethyl acetate

Contact Info

Product

Resources

About