Structure of Co(II) Species Formed on the Surface of γ-Alumina Upon Interfacial Deposition

Vakros, John; Bourikas, Kyriakos; Kordulis, Christos; Lycourghiotis, Alexis

doi:10.2174/1876214x01407010008

Cited by 1 publication

(2 citation statements)

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“…At this value, the formation of Co(OH) 2 began to increase, reaching maximum concentration at pH higher than 8.5. Some authors have reported cobalt species in solution pH values higher than 6 [19,20], in agreement with theoretical calculations. Moreover, these compounds exhibited also high stability.…”

Section: Characterizationsupporting

confidence: 80%

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CoMo/γ-Al2O3 Catalysts Prepared by Reverse Microemulsion: Synthesis and Characterization

Munguía-Guillén¹,

Reyes-Heredia²,

Picquart³

et al. 2018

Microemulsion - A Chemical Nanoreactor [Working Title]

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A series of CoMo/γ-Al 2 O 3 catalysts was synthesized by a reverse microemulsion method using 1-butanol as organic agent and cetyltrimethylammonium bromide as surfactant. The aqueous phase was used to form the solution of three corresponding Co, Mo and Al precursor salts. The materials were prepared at different solution concentrations in order to obtain different metal contents. All samples were characterized by X-ray diffraction, Raman spectroscopy, nuclear magnetic resonance and nitrogen physisorption. A chemical species distribution study was performed to establish conditions of preparation and the preponderant species present in solution as a function of pH. The materials obtained present high surface areas which decrease as the metal content (Co + Mo) increases. All samples with the exception of that with the highest metal content were amorphous as shown by X-ray diffraction. By Raman spectroscopy, MoO -Mo and MoO 2t species were observed in all calcined samples. MoO Co , Al-O-Mo, monomers and heteropolymolybdates were observed for the lower metal content samples, and the formation of CoMoO 4 and aluminum molybdate species for the higher metal contents. These results suggest that the materials with lower metal loading have species that are easily sulfidable and provide high activity in hydrodesulfurization reactions. A model for the interaction of the species in the aqueous phase of the micelle is presented.

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Section: Characterizationsupporting

confidence: 80%

“…Overall, the selected species to be obtained at the conditions fixed experimentally have been those needed for the formation of the precursors of the active species in HDS catalysts [9,19,20,25]. Table 3 gives the results for metallic loadings as determined by atomic absorption for catalysts after calcination.…”

Section: Characterizationmentioning

confidence: 99%