Preparation of supported nano-sized cobalt oxide and fcc cobalt crystallites

Fischer, Nico; Steen, Eric van; Claeys, Michael

doi:10.1016/j.cattod.2011.03.018

Cited by 79 publications

(72 citation statements)

References 28 publications

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“…In all four preparation methods tested here it was aimed to yield cobalt oxide crystallites smaller than 15 nm. Due to the differences in the reverse micelle composition in the preparation process of the four studied samples (see Table 1) we do not expect the same crystallite sizes [17]. However, the crystallite size is at this stage only of secondary interest as the main focus lies on the nature of the cobalt phase and its behaviour during reduction/activation.…”

Section: Resultsmentioning

confidence: 91%

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Metal Support Interactions in Co3O4/Al2O3 Catalysts Prepared from w/o Microemulsions

et al. 2012

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To obtain nano-sized metal and metal salt crystallites with a narrow size distribution synthesis methods utilizing water in oil (w/o) microemulsions, i.e. reverse micelles, have been widely applied and reported in literature. In this study we show the effect of support addition at different stages of the reverse micelle based preparation of cobalt oxide on alumina model catalysts. All catalysts were characterized with X-ray powder diffraction and Raman spectroscopy indicating the presence of Co 3 O 4 on the Al 2 O 3 support. Studies of the reduction behaviour and X-ray photoelectron spectroscopy however revealed the presence of difficult to reduce cobalt aluminate species in the samples where the support was added during or shortly after the precipitation step in the synthesis process. It can therefore be assumed that if the alumina support is added to the reverse micelle solution unprecipitated Co 2? ions and partially dissolved Al 3? combine and form cobalt aluminates. In the preparations where the solid cobalt precipitates are recovered from the microemulsion and then supported on the carrier, no metal-aluminate formation could be observed. This study therefore gives important information how metal-support interaction can be affected during catalyst preparation using reverse micelles.

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Section: Resultsmentioning

confidence: 91%

“…The so called reverse micelles form in the oil rich area of the ternary phase diagram. The stability region of the reverse micelles and its temperature dependency were determined previously [17].…”

Section: Preparation Of Supported Cobalt Nano Crystallitesmentioning

confidence: 99%

Metal Support Interactions in Co3O4/Al2O3 Catalysts Prepared from w/o Microemulsions

et al. 2012

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“…The first region is attributed to the Co3O4 reduction into CoO and the second one to its further reduction to metallic cobalt. 23 The TPR profile of the supports (without the presence of metals) show negligible hydrogen consumption in comparison to the Co-Na-Mo supported systems except the ceria support which presents a small reduction peak at ~850 C related to the reduction of bulk oxygen and its consequent decomposition. 24 The data in Figure 2 is normalised per mass of catalysts and therefore, differences in the amplitude of the peaks provide information related the degree of reduction of cobalt and molybdenum in the catalysts as well as the interaction with the support, however, it is important to notice that the catalysts are pre-reduced at 300 °C (shadowed area in Figure 2).…”

Section: Effect Of Support On Co2 Conversion and Selectivitymentioning

confidence: 99%

Effect of support of Co-Na-Mo catalysts on the direct conversion of CO2 to hydrocarbons

Owen

Pluciński

Mattia

et al. 2016

Journal of CO2 Utilization

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This study of the effect of support of Co-Na-Mo based catalysts on the direct hydrogenation of CO2 into hydrocarbons (HC) provides guidelines for the design of catalysts for CO2 conversion.We demonstrate that the surface area of the support and the metal-support interaction have a key role determining the cobalt crystallite size and consequently the activity of the system. Cobalt particles with sizes < 2 nm supported on MgO present low reverse water gas shift conversion with negligible Fischer-Tropsch activity. Increasing the cobalt particle size to ~ 15 nm supported on SiO2 and ZSM-5 supports not only substantially increases the CO2 conversion but it also provides high HC selectivities. Further increase of the cobalt particle size to 25-30 nm has a detrimental effect on the global CO2 conversion with HC:CO ratios below 1, however, lower methane selectivity and enhanced formation of unsaturated HC products are achieved. Additionally, the metal-support interaction potentially also has a strong effect on the growth chain probability of the formed hydrocarbons, increasing as the metal-support interaction increases. These evidences demonstrate that CO2 conversion and hydrocarbon distribution can be tuned towards desired products by controlled catalyst design.2

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“…Figure 9 shows the H 2 -TPR profile of SiO 2 -supported cobalt nanocatalyst prepared via the impregnation and reverse microemulsion methods. The first reduction stage (around 350 ºC) corresponds to reduction of Co 3 O 4 to CoO while the peak around 400 ºC was for the reduction of CoO to Co 0 (Fishcer et al, 2011). The Co/SiO 2 sample prepared via the reverse microemulsion method exhibited a second reduction stage at 700 ºC, which was much higher compared to that obtained for the sample prepared via the impregnation method indicating poorer reducibility, possibly due to strong metal-support interactions.…”

Section: Comparison Of Physicochemical Properties Between Catalysts Pmentioning

confidence: 89%

Synthesis of Nanocatalysts via Reverse Microemulsion Route for Fischer-Tropsch Reactions

Zabidi¹

2012

Microemulsions - An Introduction to Properties and Applications

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Preparation of supported nano-sized cobalt oxide and fcc cobalt crystallites

Cited by 79 publications

References 28 publications

Metal Support Interactions in Co3O4/Al2O3 Catalysts Prepared from w/o Microemulsions

Metal Support Interactions in Co3O4/Al2O3 Catalysts Prepared from w/o Microemulsions

Effect of support of Co-Na-Mo catalysts on the direct conversion of CO2 to hydrocarbons

Synthesis of Nanocatalysts via Reverse Microemulsion Route for Fischer-Tropsch Reactions

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