The effect of cerium, lanthanum and zirconium on nickel/alumina catalysts for the hydrogenation of carbon oxides

Znak, Leszek; Stołecki, K.; Zieliński, Jerzy

doi:10.1016/j.cattod.2005.01.003

Cited by 76 publications

(33 citation statements)

References 27 publications

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“…The catalysts used in the studies were obtained from 90% NiO/Al 2 O 3 precursor, prepared by coprecipitation method, consisting in mixing of Na 2 CO 3 aqueous solution with Ni(NO 3 ) 2 and Al (NO 3 ) 3 aqueous solutions (353 K, pH = 7.5) [16]. The obtained precipitate was filtered, washed, dried at 378 K, and finally calcined in air (673 K, 4 h).…”

Section: Methodsmentioning

confidence: 99%

Evolution of Metal Phase in the Course of CO Hydrogenation on Potassium Promoted Ni/Al2O3 Catalyst

2009

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The hydrogenation of carbon monoxide on Ni/Al 2 O 3 catalysts was studied in a flow system by simultaneous following CO conversion and crystallographic state of supported nickel. The examination performed for potassium promoted catalyst revealed that: (1) next to methane, considerable amount of CO 2 is produced, and (2) supported nickel transforms to supersaturated solution of carbon in nickel phase, NiC x . The analysis of the results has led to formulation of a probable scheme of the carburisation.

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Section: Methodsmentioning

confidence: 99%

Evolution of Metal Phase in the Course of CO Hydrogenation on Potassium Promoted Ni/Al2O3 Catalyst

2009

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“…Cerium oxide and cerium-promoted catalysts have been reported to exhibit catalytic activity and improve the selectivity in hydrogenation of various organic substrates [15][16][17] as well as carbon oxides [18][19][20][21][22]. However, in the literature data, there are hardly any reports on the activity of cerium compounds in hydrogenation reactions of oils and fats.…”

Section: Introductionmentioning

confidence: 78%

Characteristics and catalytic behavior of NiAlCe catalysts in the hydrogenation of canola oil: the effect of cerium on cis/trans selectivity

Konkol

Bicki

Kondracka

et al. 2016

Reac Kinet Mech Cat

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A series of co-precipitated cerium-promoted nickel-aluminum catalysts was prepared. The physicochemical properties of the precursors were analyzed by means of various methods including XRF, HT-XRD, TPR, surface area and thermal decomposition as well as porosity measurements. The activity and selectivity of the NiAlCe catalysts in the hydrogenation reaction of canola oil were investigated and the results compared to those for the cerium-free catalyst. Besides improving some physicochemical properties of the precursors, the addition of cerium significantly improved the cis/trans selectivity, yet at the expense of some loss of the activity in case of larger cerium loadings. Upon addition of a relatively low amount of cerium (0.67 wt%) the content of the C18:1 trans fraction decreased by ca. 35 %. Together with the synergistic effect of the hydrogen pressure a significant decrease of the C18:1 trans fraction by ca. 48 % could be achieved. Furthermore, compared to the cerium-free catalyst, the addition of cerium resulted in a slower drop of the C18:1 cis fraction and a slower increase of the C18:0 fraction in time during the hydrogenation process.

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“…As reported in earlier literature, the dissociation of C-O bond in adsorbed CO species is the rate-determining step in the CO methanation reaction [17,40]. When CO is adsorbed on the metal particles [41], a d-π feedback is formed by means of donation of the d-electron of nickel atoms to the vacant anti-bonding π * orbit of carbon monoxide molecule [20]. For 5Co-Ni/SiC, the d-electron density of the surface Ni atoms is increased by the effect of Co species, which can improve the proportion of d-π feedback bond and enhance the electron-feedback capacity of the metal to adsorbed CO. As a result, the Ni-C bond becomes stronger and then the C-O bond is more easily cleaved, making CO be activated more easily.…”

Section: -23 Xpsmentioning

confidence: 88%

“…Therefore, the introduction of promoters is possible to improve activity of catalysts by enhancing the adsorption amount of CO, by facilitating CO dissociation or by stabilizing intermediate species. It has been reported that the addition of La and Ce could form a new kind of active sites and promote the dissociation of carbon monoxide [19][20][21][22]. Some researchers found that the addition of Zr, V, Mo, W and Re had positive effect for the dissociation of CO and could enhance the formation of intermediate species on the catalyst surface [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

The Influence of a Second Metal on the Ni/SiC Catalyst for the Methanation of Syngas

Song¹,

Yu²,

Wang³

et al. 2014

Korean Chemical Engineering Research

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− The catalytic performance of silicon carbide supported nickel catalysts modified with or without second metal (Co, Cu and Zn) for the methanation of CO has been investigated in a fixed-bed reactor using a feed consisting of 25% CO and 75% H 2 without any diluent gas. It has been found that the introduction of Co species can clearly improve the catalytic activity of Ni/SiC catalyst, whereas the addition of Cu or Zn can result in a significant decrease in the catalytic activity. The characterizations by means of XRD, TEM, XPS, CO-TPD and H 2 -TPR indicate that the addition of Co could decrease the particle size of active metal, increase active sites on the surface of methanation catalyst, improve the chemisorption of CO and enhance the reducibility of methanation catalysts. Additionally, the special interaction between Co species and Ni species is likely favorable for the dissociation of adsorbed CO on the surface of catalyst, and this may also contribute to the high activity of 5Co-Ni/SiC catalyst for CO methanation reaction. For 5Cu-Ni/SiC catalyst and 5Zn-Ni/SiC catalyst, Cu and Zn species could cover partial nickel particles and decrease the chemisorption amount of CO. These could be responsible for the low methanation activity. In addition, a 150h stability test under 2 MPa and 300 o C showed that 5Co-Ni/SiC catalyst was very stable for CO methanation reaction.

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The effect of cerium, lanthanum and zirconium on nickel/alumina catalysts for the hydrogenation of carbon oxides

Cited by 76 publications

References 27 publications

Evolution of Metal Phase in the Course of CO Hydrogenation on Potassium Promoted Ni/Al2O3 Catalyst

Evolution of Metal Phase in the Course of CO Hydrogenation on Potassium Promoted Ni/Al2O3 Catalyst

Characteristics and catalytic behavior of NiAlCe catalysts in the hydrogenation of canola oil: the effect of cerium on cis/trans selectivity

The Influence of a Second Metal on the Ni/SiC Catalyst for the Methanation of Syngas

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