Effect of preparation conditions on the catalytic performance of cobalt manganese oxide catalysts for conversion of synthesis gas to light olefins

Mirzaei, Ali Akbar; Faizi, M K; Habibpour, Razieh

doi:10.1016/j.apcata.2006.03.036

Cited by 79 publications

(37 citation statements)

References 37 publications

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“…For example, Rao et al [19] synthesized CNTs from methane over reduced Mg 1-x Co x Al 2 O 4 (x = 0.1 -0.4) spinel catalysts with high yields and superior qualities. Co-and Mn-based mixed oxides were used in various catalytic reactions, such as the Fischer-Tropsch synthesis [20][21][22], the decomposition of nitrous oxide [23,24], and the oxidation of volatile organic compounds [25]. As an effective promoter, Mn can significantly enhance the performance of Co catalysts.…”

Section: Introductionmentioning

confidence: 99%

Optimizing the synthesis of cobalt-based catalysts for the selective growth of multiwalled carbon nanotubes under industrially relevant conditions

Becker

Xia

Tessonnier

et al. 2011

Carbon

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A An industrially applicable cobalt-based catalyst was optimized for the production of multiwalled carbon nanotubes (CNTs) from ethene in a hot-wall reactor. A series of highly active Co-Mn-Al-Mg spinel-type oxides with systematically varied Co : Mn ratios was synthesized by precipitation and calcined at different temperatures. The addition of Mn drastically enhanced the catalytic activity of the Co nanoparticles resulting in an extraordinarily high CNT yield of up to 249 gCNT/gCat. All quaternary catalysts possessed an excellent selectivity towards the growth of CNTs. The detailed characterization of the obtained CNTs by electron microscopy, Raman spectroscopy and thermogravimetry demonstrated that a higher Mn content results in a narrower CNT diameter distribution, while the morphology of the CNTs and their oxidation resistance remains rather similar. The temperature-programmed reduction of the calcined precursors as well as in-situ X-ray absorption spectroscopy investigations during the growth revealed that the remarkable promoting effect of the Mn is due to the presence of monovalent Mn(II) oxide in the working catalyst, which enhances the catalytic activity of the metallic Co nanoparticles by strong metal-oxide interactions. The observed correlations between the added Mn promotor and the catalytic performance are of high relevance for the production of CNTs on an industrial scale.

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Section: Introductionmentioning

confidence: 99%

Optimizing the synthesis of cobalt-based catalysts for the selective growth of multiwalled carbon nanotubes under industrially relevant conditions

Becker

Xia

Tessonnier

et al. 2011

Carbon

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“…For example, cobalt-zinc manganites, manganese-CeO 2 mixed oxides and Co-containing mixed oxides prepared from hydrotalcite-like precursors were active catalysts in the reduction of nitrous oxide [7][8][9]. Also, Co-Mn mixed oxides were found to be active catalysts for oxidation of ethanol [10] and conversion of synthesis gas to light olefins [11]. However, Ag-Mn, Ag-Co and Ag-Ce composite oxides supported on Al 2 O 3 have been reported as catalysts for oxidation of volatile organic compounds [12].…”

Section: Introductionmentioning

confidence: 99%

The influence of La2O3-doping on structural, surface and catalytic properties of nano-sized cobalt–manganese mixed oxides

Badawy

Ibrahim

2016

Int J Ind Chem

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Structural, textural and catalytic activity of CoO-Mn 2 O 3 system as being influenced by La 2 O 3 -doping (0.75-3 mol%) and calcination temperatures (300-500°C) were investigated. The techniques employed were XRD, N 2 -adsorption-desoprtion at -196°C, EDX and catalysis of H 2 O 2 -decomposition in aqueous solution at 30-50°C. The results revealed that the investigated system consisted of nano-sized Co 2 MnO 4 as a major phase together with unreacted portion of Co 3 O 4 and c-Mn 3 O 4 . Doping with the smallest amount of La 2 O 3 greatly increased the surface molar ratio of Mn/Co (88 %) for the solid calcined at 500°C with subsequent increase of the catalytic activity more than 12-fold for solids calcined at 500°C. The increase of La 2 O 3 -dopant above 0.75 mol% decreased progressively the surface molar ratio of Mn/Co with subsequent decrease in the catalytic activity which still measured higher values than that measured for the un-doped catalyst.

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“…In our previous study, we demonstrated the importance of aging time with respect to catalyst activity for oxidation of CO by mixed copper manganese oxide and mixed copper zinc oxide catalysts [27][28][29][30][31][32][33][34][35] and for hydrogenation of CO by mixed of cobalt-iron oxide, cobalt-manganese oxide, and cobaltcerium oxide catalysts for Fischer-Tropsch synthesis [36][37][38][39][40]. In all of these investigations, our results have shown that the aging of the precipitates obtained by coprecipitation leads to phase changes toward the forms, which are more stable thermodynamically.…”

Section: Effect Of Aging Timementioning

confidence: 99%

Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation

2011

Physical Chemistry

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Iron manganese oxides are prepared using a coprecipitation procedure and studied for the conversion of synthesis gas to light olefins and C 5 + hydrocarbons. In particular, the effect of a range of preparation variables such as [Fe]/[Mn] molar ratios of the precipitation solution, pH of precipitation, temperature of precipitation, and precipitate aging times was investigated in detail. The results are interpreted in terms of the structure of the active catalyst and it has been generally concluded that the calcined catalyst (at 650• C for 6 hours) containing 50%Fe/50%Mn-on molar basis which is the most active catalyst for the conversion of synthesis gas to light olefins. The effects of different promoters and supports with loading of optimum support on the catalytic performance of catalysts are also studied. It was found that the catalyst containing 50%Fe/50%Mn/5 wt.%Al 2 O 3 is an optimum-modified catalyst. The catalytic performance of optimal catalyst has been studied in operation conditions such as a range of reaction temperatures, H 2 /CO molar feed ratios and a range of total pressures. Characterization of both precursors and calcined catalysts is carried out by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET specific surface area and thermal analysis methods such as TGA and DSC.

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Effect of preparation conditions on the catalytic performance of cobalt manganese oxide catalysts for conversion of synthesis gas to light olefins

Cited by 79 publications

References 37 publications

Optimizing the synthesis of cobalt-based catalysts for the selective growth of multiwalled carbon nanotubes under industrially relevant conditions

Optimizing the synthesis of cobalt-based catalysts for the selective growth of multiwalled carbon nanotubes under industrially relevant conditions

The influence of La2O3-doping on structural, surface and catalytic properties of nano-sized cobalt–manganese mixed oxides

Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation

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