Characterization of Cobalt Dispersed on Various Micro- and Nanoscale Silica and Zirconia Supports

Kittiruangrayab, Sujittra; Burakorn, Tanuchnun; Jongsomjit, Bunjerd; Praserthdam, Piyasan

doi:10.1007/s10562-008-9479-4

Cited by 7 publications

(6 citation statements)

References 26 publications

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“…Here, the effect of crystallite size was more pronounced where the smaller particle can interact more retarding reduction. The similar phenomenon was also observed for the Co/ZrO2 catalyst as reported by Kittiruangrayab et al [24]. Thus, the larger particle, such as the cobalt oxide from CoN sample can be reduced more easily based on the TEM and TPR results.…”

Section: Resultssupporting

confidence: 85%

Effect of Cobalt Precursors on Properties of Co/CoAl2O4 Catalysts Synthesized by Solvothermal Method

Rojanapipatkul¹,

Goodwin²,

Praserthdam³

et al. 2012

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Abstract. In the present study, different cobalt precursors, such as cobalt acetylacetonate (CoAA), cobalt acetate (CoAC), cobalt nitrate (CoN) and cobalt chloride (CoCL), were employed to synthesize the cobalt on cobalt-aluminate catalysts by the solvothermal process. The calcined samples were characterized by means of N2 physisorption, XRD, SEM/EDX, TEM and TPR. The CO hydrogenation under methanation condition was performed to measure the activity and product distribution. It revealed that the CoN sample exhibited the highest activity due to high reducibility and large crystallite size having fewer interactions. The similar trend was observed for the CoAC and CoAA samples. However, the CoCL sample had the lowest activity, but highest selectivity to C2-C4 products. This was likely attributed to the different form of cobalt oxide species obtained from CoCl2 as seen from XRD.

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Section: Resultssupporting

confidence: 85%

Effect of Cobalt Precursors on Properties of Co/CoAl2O4 Catalysts Synthesized by Solvothermal Method

Rojanapipatkul¹,

Goodwin²,

Praserthdam³

et al. 2012

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“…The significant increase in the size of crystallites upon increase in contribution of the monoclinic phase has been noted earlier during study of the reaction of cobalt with the surface of zirconia by elec tron microscopy and X ray diffraction. 10 The TPR curves of the 10%Co/ZrO 2 catalysts are shown in Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

Formation of the Co/ZrO2 catalyst active phase in the Fischer—Tropsch synthesis

Лапидус

Grigor’ev²,

Михайлов

et al. 2010

Russ Chem Bull

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Thermoprogrammed reduction and X ray powder diffraction were used to study the phase composition and specific features of the activation process of the Co/ZrO 2 catalytic system. Results of the physico chemical studies were compared with the data on activity and selectivity of catalysts in the Fischer-Tropsch synthesis. Reducing activation of the Co/ZrO 2 catalyst with the syn gas can be performed directly during the Fischer-Tropsch synthesis, avoiding the high temperature step of reduction with hydrogen. The Co/ZrO 2 catalytic system can be used for the development of catalysts for the Fischer-Tropsch synthesis, which do not require a separate step of the high temperature reduction with hydrogen.Classic cobalt Fischer-Tropsch catalysts based on alu mina, silica, and alumosilicates possess high activity and selectivity. 1,2 One of the principal steps in the formation of active phase of these catalysts is the activation in re ducing atmosphere, necessary for the formation of re duced particles of cobalt on the catalyst surface. 3 Recent works 4-7 showed that when a precursor of the active component is deposited on a support, formation of dif ficult to reduce mixed oxides (spinel structures) 8,9 occurs, that leads to the transformation of considerable amount of active component into the catalytically inert state.Since formation of the spinel structures is directly re lated to the active component-support interaction, more recently attention of researches was directed on the development of new catalytic systems with lower strength of the metal-support interaction. In particu lar, the Co/ZrO 2 system belongs to such systems (see Ref. 10).In the present work, we studied conditions for the for mation of active phase in the Co/ZrO 2 catalytic system and their influence on activity and selectivity of the Fischer-Tropsch catalyst.

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“…The TPR profile of the Co/C catalyst is characterized by weak hydrogen uptake in the temperature range of 200-250 • C with a maximum at 228 • C, as well as hydrogen uptake at the higher temperature range of ~250-500 • C. The second peak includes several components, probably due to the reduction of particles differing in size. It has a higher intensity than the first peak and is characterized by a maximum at 358 • C. Low-temperature absorption of hydrogen is associated with the reduction of Co 3 O 4 to CoO, and the peak that appears at a higher temperature is associated with the further reduction of CoO particles to metallic cobalt [37][38][39][40].…”

Section: Temperature-programmed Reductionmentioning

confidence: 98%

Selective Hydrogenation of Acetylene over Pd-Co/C Catalysts: The Modifying Effect of Cobalt

et al. 2023

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Novel bimetallic Pd-Co catalysts supported on the carbon material Sibunit were synthesized by an incipient wetness impregnation method and used for ethylene production by selective acetylene hydrogenation. It has been established that an increase in the Pd:Co molar ratio from 1:0 to 1:2 in 0.5%Pd-Co/C catalysts, treated in hydrogen at 500 °C, leads to an increase in the ethylene selectivity from 60 to 67% (T = 45 °C). The selectivity does not change with a further increase in the modifier concentration. The catalysts were investigated by TPR-H2, XRD, TEM HR, EDS, and XPS methods. It was shown that palladium and cobalt in the 0.5%Pd-Co/C samples form Pd(1−x)Cox phases of solid solutions with different compositions depending on the Pd:Co ratio. The cobalt concentration in the Pd-Co particles increases with an increase in the Pd:Co ratio up to 1:2 and then remains at a constant level. In addition, monometallic Co particles were present in the samples with the Pd:Co ratio higher then 1:2. The optimal combination of catalytic properties (the ethylene yield is 62–63%) is typical for catalysts with a Pd:Co molar ratio of 1:2–1:4. which is mainly due to the presence of bimetallic particles containing ~41–43% by at. of cobalt.

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Characterization of Cobalt Dispersed on Various Micro- and Nanoscale Silica and Zirconia Supports

Cited by 7 publications

References 26 publications

Effect of Cobalt Precursors on Properties of Co/CoAl2O4 Catalysts Synthesized by Solvothermal Method

Effect of Cobalt Precursors on Properties of Co/CoAl2O4 Catalysts Synthesized by Solvothermal Method

Formation of the Co/ZrO2 catalyst active phase in the Fischer—Tropsch synthesis

Selective Hydrogenation of Acetylene over Pd-Co/C Catalysts: The Modifying Effect of Cobalt

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