Alumina-supported Ni catalysts modified with silver for the steam reforming of methane: Effect of Ag on the control of coke formation

Parizotto, N.V.; Rocha, K.O.; Damyanova, S.; Passos, Fábio B.; Zanchet, Daniela; Marques, C.M.P.; Bueno, J.M.C.

doi:10.1016/j.apcata.2007.06.022

Cited by 142 publications

(61 citation statements)

References 37 publications

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“…The metal particles size of the catalysts show no significant change upon addition of Ag. This finding is also confirmed by Parizotto et al [6]. However, four additional peaks appear at 2θ of 38.2°, 44.4°, 64.5° and 77.5°, which coincide with peaks of Ag.…”

Section: Catalytic Reaction Performancesupporting

confidence: 80%

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Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

Harun

Gimbun

Azizan

et al. 2016

Bull. Chem. React. Eng. Catal.

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The carbon dioxide (CO2) dry reforming of glycerol for syngas production is one of the promising ways to benefit the oversupply crisis of glycerol worldwide. It is an attractive process as it converts carbon dioxide, a greenhouse gas into a synthesis gas and simultaneously removed from the carbon biosphere cycle. In this study, the glycerol dry reforming was carried out using Silver (Ag) promoted Nickel (Ni) based catalysts supported on silicon oxide (SiO2), i.e. Ag-Ni/SiO2. The catalysts were prepared through wet impregnation method and characterized by using Brunauer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Thermo Gravimetric (TGA) analysis. The experiment was conducted in a tubular reactor which condition fixed at 973 K and CO2 to glycerol molar ratio of 1, under atmospheric pressure. It was found that the main gaseous products are H₂, CO and CH4 with H₂:CO molar ratio < 1.0. From the reaction study, Ag(5)-Ni/SiO2 results in highest glycerol conversion and hydrogen yield, accounted for 32.6% and 27.4%, respectively.

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Section: Catalytic Reaction Performancesupporting

confidence: 80%

“…Ag is uncommonly used in dry reforming studies. Nevertheless, Ag has been reported possessing the ability to inhibit the formation of coke and thus maintain the stability of the catalyst [6,7]. Moreover, Ag as the promoter improves the ethanol conversion and hydrogen selectivity in ethanol steam reforming, as reported by Chen et al [8].…”

Section: Introductionmentioning

confidence: 78%

Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

Harun

Gimbun

Azizan

et al. 2016

Bull. Chem. React. Eng. Catal.

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“…The presence of other noble metals, which are themselves inactive in this reaction, was reported to be beneficial to minimize surface coke formation. Silver on Ni/Al 2 O 3 catalyst altered the superficial structure of nickel which lead to negligible carbon formation during DRM [27]. Similar behavior was experienced when Ni-Au bimetallic nanoparticles were deposited onto MgAl 2 O 4 : the amount of deactivating carbon decreased during dry reforming [28].…”

Section: Introductionsupporting

confidence: 49%

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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“…The catalysts with Ag loading of 0.3 or 0.6 wt% submitted to stability tests showed high resistance to coke deposition reported by Bueno et al [32]. They further found that at more oxidant conditions (autothermal reforming of methane, ATRM and POM) the redox process led to NiO formation and catalyst deactivation by NiAl 2 O 4 formation [33].…”

Section: Catalytic Activity Of Ni-au Catalysts and Comparison With Otmentioning

confidence: 70%

“…Bueno and co-workers have prepared Ni/γ-Al 2 O 3 modified with Ag by co-impregnation method [32,33]. The impregnated samples were dried at 353 K overnight and calcined under flowing air at 723 K for 2 h. Finally, the samples were reduced in H 2 flow, heated at 10 K/min and held at 1073 K for 2 h. Figure 3 shows the in situ Ni K-edge XANES-TPR-H 2 spectra of the oxidized 5 wt% Ni/γ-Al 2 O 3 and that doped by 0.6 wt% Ag at different temperatures.…”

Section: Ni Metal Particles Modified With Agmentioning

confidence: 99%

Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

et al. 2013

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Steam reforming of light hydrocarbons provides a promising method for hydrogen production. Ni-based catalysts are so far the best and the most commonly used catalysts for steam reforming because of their acceptably high activity and significantly lower cost in comparison with alternative precious metal-based catalysts. However, nickel catalysts are susceptible to deactivation from the deposition of carbon, even when operating at steam-to-carbon ratios predicted to be thermodynamically outside of the carbon-forming regime. Reactivity and deactivation by carbon formation can be tuned by modifying Ni surfaces with a second metal, such as Au through alloy formation. In the present review, we summarize the very recent progress in the design, synthesis, and characterization of supported bimetallic Ni-based catalysts for steam reforming. The progress in the modification of Ni with noble metals (such as Au and Ag) is discussed in terms of preparation, characterization and pretreatment methods. Moreover, the comparison with the effects of other metals (such as Sn, Cu, Co, Mo, Fe, Gd and B) is addressed. The differences of catalytic activity, thermal stability and carbon species OPEN ACCESSCatalysts 2013, 3 564 between bimetallic and monometallic Ni-based catalysts are also briefly shown.

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Alumina-supported Ni catalysts modified with silver for the steam reforming of methane: Effect of Ag on the control of coke formation

Cited by 142 publications

References 37 publications

Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

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

Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

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