Gas-Uptake, Methanation, and Microcalorimetric Measurements on the Coadsorption of CO and H2over Polycrystalline Ru and a Ru/TiO2Catalyst

Gupta, Nandini; Londhe, V.P.; Kamble, V.S.

doi:10.1006/jcat.1997.1718

Cited by 50 publications

(32 citation statements)

References 21 publications

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“…It has been proposed that CO dissociates in the initial step leading to two types of carbon species, namely active and inactive. Then, the former type is stepwise methanated to CH 4 through various adsorbed intermediate species, such as CH, CH 2 , and CH 3 . However, transient experiments have shown that these adsorbed CH x species represent side products rather than the reaction intermediates …”

Section: Resultsmentioning

confidence: 99%

CO methanation toward the production of synthetic natural gas over highly active Ni/TiO₂ catalyst

Shinde

Madras

2013

AIChE Journal

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in Wiley Online Library (wileyonlinelibrary.com)The sonochemical synthesis and characterization of highly active and stable Ni nanoparticles supported on TiO 2 as a CO methanation catalyst for the production of synthetic natural gas are reported. The catalyst synthesized by sonication showed higher activity for CH 4 formation than the catalyst synthesized via the conventional wet impregnation method. The activation energy was found to be 79 and 94 kJ mol 21 for the catalyst synthesized with sonication and wet impregnation method, respectively. The combined results of x-ray photoelectron spectroscopy and x-ray diffraction show that the enhancement in activity of the sample synthesized by sonication method is due to partial substitution of Ni in TiO 2 lattice. This creates oxide vacancies and facilitates hydrogen adsorption and spillover from nickel to support. H 2temperature-programmed reduction study corroborates the intimate contact of Ni with support, thus rendering strong metal support interactions. The mechanism involving Langmuir-Hinshelwood kinetics with hydrogen-assisted CO dissociation was used to correlate experimental data.The catalytic activity measurement was performed at atmospheric pressure in a tubular quartz reactor (4-mm ID and length of 30 cm) over 0.5 g of catalyst (40-80 mesh) Figure 4. H 2 -TPR profile for (a) 23%Ni/TiO 2 (imp), (b) 23%Ni/TiO 2 (sonic), and (c) nickel oxide.Figure 5. Percentage (a) CO conversion, (b) CH 4 selectivity, and (c) CH 4 yield plot on various TiO 2modified catalysts.

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Section: Resultsmentioning

confidence: 99%

CO methanation toward the production of synthetic natural gas over highly active Ni/TiO₂ catalyst

Shinde

Madras

2013

AIChE Journal

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“…Most prominenti na ll spectra (Figure 8a ,w hich are assigned to linearly on-top adsorbed and bridge-bonded CO ad species. [26,[35][36][37][38] Moreover,t here is also aw eak absorption band at ñ = 1756 cm À1 in all spectra, which is related to hydroformyl species (HCO ad )t hat result from hydrogenation of CO ad . [34] This species was previously identified as ad ominant reaction intermediate during the methanation of CO and CO 2 over aR u/Al 2 O 3 catalyst.…”

Section: Time Evolution Of the Adlayermentioning

confidence: 99%

Improved Performance of Ru/γ‐Al₂O₃ Catalysts in the Selective Methanation of CO in CO₂‐Rich Reformate Gases upon Transient Exposure to Water‐Containing Reaction Gas

et al. 2015

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To better understand the role of water in the selective methanation of CO in CO2-rich reformate gases on Ru/Al2O3 catalysts, the influence of exposing these catalysts to H2O-rich reformate gases on their reaction characteristics in transient experiments was investigated by employing kinetic and in situ spectroscopic measurements as well as ex situ catalyst characterization. Transient exposure of the ruthenium catalyst to wet reaction gas (5 or 15% H2O) results in significantly enhanced activity and selectivity for CO methanation in subsequent reactions in dry reformate compared with activation and reaction in dry reformate directly. Operando X-ray absorption spectroscopy results reveal that this is in accordance with a significant decrease in ruthenium particle size, which is stable during subsequent reaction in dry reformate. The implications of these data and additional results from in situ IR spectroscopy on the role and influence of H2O on the reaction, also in technical applications, are discussed.

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“…The measurements were , depending on the CO content in the gas mixture, which are generally attributed to CO adsorbed in a linear or bridged configuration on the Ru NPs, respectively [24, [35][36][37][38][39][40][41][42][43]. A signal at 2075 cm -1 was assigned previously to CO adsorbed on Ru n+ species [40,44].…”

Section: In-situ Drifts Measurementsmentioning

confidence: 99%

Influence of the catalyst loading on the activity and the CO selectivity of supported Ru catalysts in the selective methanation of CO in CO2 containing feed gases

Eckle

Augustin

Anfang³

et al. 2012

Catalysis Today

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We have investigated the methanation of CO and CO 2 over Ru/zeolite catalysts with different Ru loading in semi-realistic reformate gases by in situ X-ray absorption spectroscopy (XAS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and kinetic measurements. Increasing the Ru loading causes an increase of the mean particle size from 0.9 nm (2.2 wt.% Ru) to 1.9 nm (5.6 wt.% Ru). At the same time, also the activity for CO methanation increases, while the selectivity for CO methanation, which is constant at 100% for reformate gases with 0.6% CO, decreases at low CO contents. The latter findings are interpreted in terms of a change in the physical effects governing the selectivity for CO methanation with increasing Ru particle size, from an inherently low activity for CO 2 dissociation and subsequent CO ad methanation on very small Ru nanoparticles to a site blocking mechanism on larger Ru nanoparticles. In the latter mechanism, CO 2 methanation is hindered by a reaction inhibiting adlayer of CO at higher CO ad coverages, i.e., at not too low CO concentrations, but facile in the absence of a CO adlayer, at lower CO concentrations in the reaction gas mixture.

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Gas-Uptake, Methanation, and Microcalorimetric Measurements on the Coadsorption of CO and H2over Polycrystalline Ru and a Ru/TiO2Catalyst

Cited by 50 publications

References 21 publications

CO methanation toward the production of synthetic natural gas over highly active Ni/TiO₂ catalyst

CO methanation toward the production of synthetic natural gas over highly active Ni/TiO₂ catalyst

Improved Performance of Ru/γ‐Al₂O₃ Catalysts in the Selective Methanation of CO in CO₂‐Rich Reformate Gases upon Transient Exposure to Water‐Containing Reaction Gas

Influence of the catalyst loading on the activity and the CO selectivity of supported Ru catalysts in the selective methanation of CO in CO2 containing feed gases

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Gas-Uptake, Methanation, and Microcalorimetric Measurements on the Coadsorption of CO and H2over Polycrystalline Ru and a Ru/TiO2Catalyst

Cited by 50 publications

References 21 publications

CO methanation toward the production of synthetic natural gas over highly active Ni/TiO2 catalyst

CO methanation toward the production of synthetic natural gas over highly active Ni/TiO2 catalyst

Improved Performance of Ru/γ‐Al2O3 Catalysts in the Selective Methanation of CO in CO2‐Rich Reformate Gases upon Transient Exposure to Water‐Containing Reaction Gas

Influence of the catalyst loading on the activity and the CO selectivity of supported Ru catalysts in the selective methanation of CO in CO2 containing feed gases

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CO methanation toward the production of synthetic natural gas over highly active Ni/TiO₂ catalyst

CO methanation toward the production of synthetic natural gas over highly active Ni/TiO₂ catalyst

Improved Performance of Ru/γ‐Al₂O₃ Catalysts in the Selective Methanation of CO in CO₂‐Rich Reformate Gases upon Transient Exposure to Water‐Containing Reaction Gas