Carbon dioxide reforming of methane over lanthanum-modified catalysts in a fluidized-bed reactor

Blom, Richard; Dahl, Ivar M.; Slagtem, Åse; Sortland, Bjørn; Spjelkavik, Aud I.; Tangstad, Elisabeth

doi:10.1016/0920-5861(94)80177-0

Cited by 87 publications

(21 citation statements)

References 16 publications

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“…The increase in the temperature of calcination from 773 up to 1173 K leads to a significant decrease in the S BET and V p corresponding to formation of micropores. The observed influence of CeO 2 loading on the thermal stability of alumina is similar to previous observations in the literature [19,20]. Pt catalysts supported on Al 2 O 3 , CeO 2 and CeO 2 -Al 2 O 3 show surface areas and pore volume similar to those of the supports (Table 1).…”

Section: Characterization Of the Supports And Catalystssupporting

confidence: 89%

The effect of ceria content on the performance of Pt/CeO/AlO catalysts in the partial oxidation of methane

Santos

Damyanova

Teixeira

et al. 2005

Applied Catalysis A: General

124

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Section: Characterization Of the Supports And Catalystssupporting

confidence: 89%

The effect of ceria content on the performance of Pt/CeO/AlO catalysts in the partial oxidation of methane

Santos

Damyanova

Teixeira

et al. 2005

Applied Catalysis A: General

124

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“…But a broad peak at 2h of 30°for LaO is observed when the atomic ratio of La/Pd = 3-5. The La 2 O 3 , LaAlO 3 and LaAl 12 O 19 phases are not observed by the XRD, which is quite different from the literature works [22]. The results indicate that the lanthanum, as the phase of LaO, could disperse uniformly on the Al 2 O 3 when the atomic ratio of La/Pd \ 1.…”

Section: Resultscontrasting

confidence: 78%

Lanthanum-promoted Pd/Al2O3 catalysts for liquid phase in situ hydrogenation of phenol to cyclohexanone

Xiang

Kong

et al. 2010

Reac Kinet Mech Cat

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A series of lanthanum-promoted Pd/Al 2 O 3 catalysts (Pd/La x -Al 2 O 3 ), for the liquid phase in situ hydrogenation of phenol into cyclohexanone, was prepared by the incipient wetness impregnation method. Addition of lanthanum to Pd/Al 2 O 3 enhances the TOF of the catalyst for the liquid phase in situ hydrogenation of phenol significantly. The conversion of phenol is highly dependent upon the atomic ratio of La/Pd, but the presence of lanthanum has little effect on the selectivity of cyclohexanone. The selectivity of cyclohexanone in the liquid phase in situ hydrogenation of phenol over the Pd/La x -Al 2 O 3 catalyst is as high as 98%, which is quite higher than the hydrogenation using H 2 (67.4%). Results from BET, EDS, CO chemosorption, XRD and H 2 -TPR suggest that the presence of suitable amounts of lanthanum improves the Pd dispersion on the support. The peak temperature for the reduction of PdO in the H 2 -TPR moves to higher in the presence of lanthanum. Additionally, the Pd particles could adhere to the lanthanum rather than the Al 2 O 3 .

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“…The origin of the interaction between NiO particles and support remains a matter of controversy, and not unambiguous theoretical explanation of this phenomenon has yet been offered. Two different explanations about the origin of this interaction appear in the studies published in literature: (i), nickel ocupying different sites in the alumina, octahedral or tetrahedral, this latter more difficult to reduce [26,27]; or (ii), the incorporation of Al 3+ [13], Ce 3+ [28] or La 3+ [29] ions on the surface of NiO particles during impregnation. The latter possibility is in accordance with XPS characterization of calcined catalysts (Table 6) since the absence of Ni 2p 3/2 signal corresponding to NiO species together with the low Ni/Al surface XPS ratios seem to indicate that in all catalysts the surface of NiO particles is covered by dispersed support species.…”

Section: Structure Of Nickel Catalystsmentioning

confidence: 99%

Hydrogen Production from Glycerol Over Nickel Catalysts Supported on Al2O3 Modified by Mg, Zr, Ce or La

et al. 2008

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Hydrogen production from glycerol reforming in liquid (aqueous phase reforming, APR) and vapor (steam reforming SR) phase over alumina-supported nickel catalysts modified with Ce, Mg, Zr and La was studied. Characterization of catalysts by temperature programmed reduction and XPS analyses revealed important structural effects: (i) the intercalation of Mg between nickel and alumina that inhibited the alumina incorporation to nickel phases, (ii) the close contact between Ni and Zr phases and, (iii) the close surface interaction of La and Ce ions with NiO phases. The catalytic activity of the samples studied in this work clearly indicated the different catalyst functionalities necessary to carry out aqueous-phase and vaporphase steam reforming of glycerol. For aqueous phase reforming of glycerol, the addition of Ce, La and Zr to Ni/ Al 2 O 3 improves the initial glycerol conversions obtained over the Ni/Al 2 O 3 supported catalyst. It is suggested that the differences in catalytic activities are related with geometric effects caused by the decoration of Ni phases by Ce and La or by the close interaction between Ni and Zr. In spite that nickel catalysts showed high APR activities at initial times on stream, all samples showed, independently of support, important deactivation rates that deactivate the catalysts after few hours under operation. Catalysts characterization after APR showed the oxidation of the active metallic Ni during reaction as the main cause of the observed deactivation. In the case of the glycerol steam reforming in vapor phase, the use of Ce, La, Mg and Zr as promoters of Ni based catalysts increases the hydrogen selectivity. Differences in activity were explained in terms of enhancement in: surface nickel concentration (Mg), capacity to activate steam (Zr) and stability of nickel phases under reaction conditions (Ce and La).

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Carbon dioxide reforming of methane over lanthanum-modified catalysts in a fluidized-bed reactor

Cited by 87 publications

References 16 publications

The effect of ceria content on the performance of Pt/CeO/AlO catalysts in the partial oxidation of methane

The effect of ceria content on the performance of Pt/CeO/AlO catalysts in the partial oxidation of methane

Lanthanum-promoted Pd/Al2O3 catalysts for liquid phase in situ hydrogenation of phenol to cyclohexanone

Hydrogen Production from Glycerol Over Nickel Catalysts Supported on Al2O3 Modified by Mg, Zr, Ce or La

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