Stability promotion of Ni/α-Al2O3 catalysts by tin added via surface organometallic chemistry on metals

Nichio, Nora N.; Casella, Mónica Laura; Santori, Gerardo Fabián; Ponzi, Esther N.; Ferretti, Osmar A.

doi:10.1016/s0920-5861(00)00424-7

Cited by 57 publications

(55 citation statements)

References 34 publications

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“…From the electronic structure of Pb, it was clear that Pb atom contains same amount of ''spare'' p electrons in its outer shell as carbon, when Pb was added to the supported Ni catalyst, its ''spare'' p electrons might react with the 3d electrons of nickel to form some kind of surface compounds as it was predicted [21] and confirmed in Ni-Sn system [24][25][26]. This kind of surface compounds can resist the formation of nickel carbide in some extent and then retarded the deposition of carbon.…”

Section: Resultsmentioning

confidence: 86%

“…Some metals (such as Ge, Sn, Pb, As, Sb or Bi) possess similar electronic structure as carbon, as all of them contain ''spare'' p electrons in their outer shell close to a stable s-orbital, that is, it is possible for these metals to react with Ni 3d electrons, and then reduce the formation of nickel carbide [21]. Among these recommended elements, the excellent promotion effect of Sn were confirmed by Trimm [21], Nicho et al [24,25] and our previous work [26]. It was found that small amounts of Sn doped Ni catalysts exhibited excellent coke resistance ability in the dry reforming process of CH 4 .…”

Section: Introductionmentioning

confidence: 96%

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Doped Ni Catalysts for Methane Reforming with CO2

et al. 2004

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Pb, Sb, Bi and Te doped Ni catalysts were prepared and used for methane reforming with CO 2 in order to diminish coke deposition. It was found that small amounts of Pb doped Ni catalysts exhibited excellent coke resistance ability with minor loss of the reforming activity. As the added amount of Pb increased from 0 to 0.015 (mole ratio between Pb/Ni), coke formation rate decreased from 166.7 mg-coke/g-cat h (on Ni/SiO 2 ) to 0, while the reforming activity decreased slightly from 73.2% to 63.3% (conversion of CO 2 ) at 800°C, 60,000 ml(STP)/g-catÁh (CH 4 CO 2 =1:1, no dilution gas in feed). Higher amounts of Pb and Sb, Bi, Te made Ni catalyst deactivated for methane reforming with CO 2 .

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Section: Resultsmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 96%

Doped Ni Catalysts for Methane Reforming with CO2

et al. 2004

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“…Tin containing yttria-stabilized zirconia supported nickel catalyst showed outstanding stability in steam reforming of methane which was explained by the decreased carbon formation due to enrichment of tin on the surface of nickel particles [32]. Selective modification of nickel surface on Ni/a-Al 2 O 3 catalyst by grafting tetrabutyltin and its subsequent reduction resulted in higher stability and negligible carbon formation compared to the unmodified catalyst [33]. It is worth mentioning that catalysts prepared by co-impregnation had the same properties, that is a coke-free operation without the loss of catalytic activity was observed in the presence of small amount of tin on the catalyst [34].…”

Section: Introductionmentioning

confidence: 99%

Carbon dioxide reforming of methane over Ni–In/SiO2 catalyst without coke formation

Károlyi

Németh

Evangelisti

et al. 2018

Journal of Industrial and Engineering Chemistry

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Keywords dry reforming of methane, silica supported nickel catalyst, nickel-indium bimetallic catalyst, coke formation, biogas conversion Highlights· Ni-In/SiO 2 catalysts were prepared by deposition-precipitation with urea. · Both metals were in metallic state after reduction at 700 °C. · Interaction of the two metals was evidenced by TPR, XPS. · The presence of indium in the close vicinity of nickel prevents coke formation. Graphical abstract AbstractThe development of a carbon tolerant nickel catalyst for carbon dioxide reforming of methane (dry reforming of methane, DRM) has been in the focus of catalysis research for several years.In the present study, 3wt%Ni/SiO 2 and bimetallic 3wt%Ni-2wt%In/SiO 2 catalysts (corresponding to 3:1 Ni:In ratio) were prepared by deposition precipitation with urea. Our intention was to modify the nickel surface with a second metal which is known from its ability to reduce surface coke formation. A methane rich reaction mixture (CH 4 :CO 2 :Ar = 2 69:30:1) was used for the catalytic tests at 600 °C and 675 °C. TPO measurements after the catalytic tests showed that there was no surface carbon formation on the indium containing catalyst.Temperature-programmed reduction measurements of the catalysts showed that both nickel and indium was completely reduced after one hour reduction at 700 °C suggesting interaction of the two metals. CO pulse chemisorption experiments revealed that the particle size was similar on the monometallic and bimetallic catalyst, and CO-TPD measurements showed completely different desorption behavior of CO, suggesting the presence of different active sites on the two catalysts. XPS experiments gave similar results, furthermore it was found that after reduction, the Ni/In ratio on the surface was 2.2 compared to the initial value (~3), which refers to the surface enrichment of indium in the bimetallic particles.The lack of coke formation on the indium containing catalyst might be explained by the interplay between a geometric and a chemical effect, that is, indium atoms are most likely situated on the edge and step sites of a nickel particle, influencing reactant adsorption and hindering the growth of carbon nanostructures and/or providing an oxygen rich indium suboxide surface through the reaction with CO 2 in the close vicinity of catalytically active nickel sites, which also inhibits the accumulation of carbon deposits during DRM.

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“…Starting from the first works [8][9][10][11] up to date, two main classes of catalysts have been studied for CPO and ATR, containing Ni [12][13][14][15][16][17][18][19][20] or noble metals [15,[21][22][23][24][25][26][27][28][29][30][31][32][33] as active phase. Although more expensive than Ni-based catalysts, noble metals (generally Pt and Rh) appear to be very attractive because of their high activity, allowing the development of processes at short contact time (SCT), and no coke formation [9].…”

Section: Introductionmentioning

confidence: 99%

Partial Oxidation and CO2-ATR of Methane over Rh/LaMnO3 Honeycomb Catalysts

Barbato

Landi²

2010

Catal Lett

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Catalytic partial oxidation of methane has been studied over structured bi-functional catalysts containing LaMnO 3 perovskite and Rh. The effects of the noble metal content and of substrate morphology and thermal conductivity have been investigated under high temperature pseudo-adiabatic conditions. Several reaction conditions have been explored by means of changing CH 4 /O 2 ratio and GHSV and of adding CO 2 . Synergistic effect between active phases has been detected even if best performance has been expressed by the catalyst containing the largest amount of Rh. Catalytic performance can be improved by a proper choice of the substrate; high cell density honeycombs showed increased syngas yields, while a better heat management can be obtained depositing the active phase onto high thermal conductivity substrate. H 2 /CO ratio can be modified by CO 2 addition.

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Stability promotion of Ni/α-Al2O3 catalysts by tin added via surface organometallic chemistry on metals

Cited by 57 publications

References 34 publications

Doped Ni Catalysts for Methane Reforming with CO2

Doped Ni Catalysts for Methane Reforming with CO2

Carbon dioxide reforming of methane over Ni–In/SiO2 catalyst without coke formation

Partial Oxidation and CO2-ATR of Methane over Rh/LaMnO3 Honeycomb Catalysts

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