Impregnated Ni/ZrO2 and Pt/ZrO2 catalysts in dry reforming of methane: Activity tests in excess methane and mechanistic studies with labeled 13CO2

Németh, Miklós; Schay, Z.; Srankó, Dávid Ferenc; Károlyi, J.; Sáfrán, György; Sajó, István E.; Horváth, Anita

doi:10.1016/j.apcata.2015.04.006

Cited by 56 publications

(37 citation statements)

References 35 publications

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“…The CO/H 2 ratio, which stabilizes at around 1.45 after two hours at 600 °C in each case. This value is higher than the equilibrium (CO/H 2 ~ 1.2) at this temperature [47] which usually means that some CO is produced via the reverse water-gas shift (RWGS) that is a dominant side reaction [47], [48]. TPO curves after the reaction showed that the amount of carbon deposited on the surface increased after each catalytic cycles, so it can be concluded that in our case, the coke, deposited during reaction, does not influence the catalytic activity of Ni/SiO 2 catalyst.…”

Section: Chemical State Of Nickel and Indium In The Bimetallic Catalystsmentioning

confidence: 72%

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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Section: Chemical State Of Nickel and Indium In The Bimetallic Catalystsmentioning

confidence: 72%

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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“…In spectra of NiPS, a strong peak at

\overset{ν}{true}

=2047 cm −1 that occurs from 400 °C is assigned to linear CO adsorption on Ni . The peak at

\overset{ν}{true}

=1932 cm −1 can be assigned to bridging CO adsorption on Ni, and the peak at

\overset{ν}{true}

=1802 cm −1 is attributed to another type of CO adsorption on bridged Ni sites .…”

Section: Resultsmentioning

confidence: 99%

Sandwich‐Like Silica@Ni@Silica Multicore–Shell Catalyst for the Low‐Temperature Dry Reforming of Methane: Confinement Effect Against Carbon Formation

2017

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We synthesize a new sandwich‐like silica@Ni@silica multicore–shell catalyst. Firstly, Ni phyllosilicate (NiPS) is supported on silica nanospheres by a simple ammonia evaporation method. Then NiPS is coated with a layer of mesoporous silica to obtain a core–shell NiPS@silica structure by the hydrolysis of tetraethylorthosilicate (TEOS). The thickness of the shell can be tuned by varying the amount of TEOS. After calcination and H2 reduction at high temperature, multiple small Ni nanoparticles (≈6 nm) are generated and supported on the inner silica core but also encapsulated within the outer mesoporous silica shell. This silica@Ni@silica multicore–shell catalyst shows a high and stable conversion (≈60 %, gas hourly space velocity=60 000 mL h−1 gcat−1) for the dry reforming of methane (DRM) at 600 °C, whereas pristine NiPS deactivates quickly because of heavy carbon formation. We investigated the spent catalysts by using thermogravimetric analysis and TEM and found that there is almost no carbon formation for this new multicore–shell catalyst. Compared with a conventional Ni@silica core–shell catalyst, our multicore–shell catalyst is much easier to synthesize and the process does not require any toxic organic solvents. We believe that this strategy to make a multicore–shell catalyst can be applied to more nanomaterials and extended to other catalytic reactions besides DRM.

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“…However, serious carbon deposition and metal sintering cause the deactivation of Ni-based catalyst [8,[13][14][16][17][18][19][20][22][23][24][25][26][27][28]. In order to improve the Ni based catalysts, several approaches have been used to decrease the particle size (enhance the metal dispersion) and promoting the MSI, which are reported to be effective in depressing the carbon and preventing the metal-sintering, leading to a high activity and stability [29,30].…”

Section: Introductionmentioning

confidence: 99%

“…Supported Ni catalysts are widely studied for dry reforming of methane due to its high reactivity and low cost [19][20][21]. However, serious carbon deposition and metal sintering cause the deactivation of Ni-based catalyst [8,[13][14][16][17][18][19][20][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Ni/SiO2 catalyst prepared via Ni-aliphatic amine complexation for dry reforming of methane: Effect of carbon chain number and amine concentration

Gao

Ashok

Widjaja

et al. 2015

Applied Catalysis A: General

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Impregnated Ni/ZrO2 and Pt/ZrO2 catalysts in dry reforming of methane: Activity tests in excess methane and mechanistic studies with labeled 13CO2

Cited by 56 publications

References 35 publications

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

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

Sandwich‐Like Silica@Ni@Silica Multicore–Shell Catalyst for the Low‐Temperature Dry Reforming of Methane: Confinement Effect Against Carbon Formation

Ni/SiO2 catalyst prepared via Ni-aliphatic amine complexation for dry reforming of methane: Effect of carbon chain number and amine concentration

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