Influence of ceria on the interaction of CO and NO with highly dispersed Pt and Rh

Lööf, Peter; Kasemo, Bengt Herbert; Andersson, S.; Frestad, A.

doi:10.1016/0021-9517(91)90102-a

Cited by 101 publications

(11 citation statements)

References 17 publications

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“…It has been shown in other studies (Morrow et al, 1985;Loof et al, 1991) that the adsorbed NO decomposes almost completely to gaseous N, and adsorbed oxygen on a Pt/Al,O, catalyst at 500 K, and only small amounts of N,O formation have been observed (Loof et al, 1991), whicKis consistent with the observation in Figure 6(a). The CO, concentration does not fall to zero even by the end of NO half-cycle due to CO, desorption from the alumina support.…”

Section: Transient Responsesupporting

confidence: 91%

Transient and resonant behavior for no reduction by CO over a Pt/Al₂O₃ catalyst during forced composition cycling

Sadhankar

Lynch

1996

Can J Chem Eng

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The reduction of NO by CO over a Pt/AI,O, catalyst has been investigated using the technique of forced concentration cycling in an isothermal recycle reactor at 485 K. Time-average conversions exhibit resonant behavior with increasing frequency. Maximum time-average NO conversion of 78%, compared with the steady-state conversion of 3.8%, was attained during out-of-phase feed concentration cycling. The effect of the phase angle between the NO and CO feed cycles has been examined. Higher conversions are obtained by decreasing the NO phase lead below 180". The convergence to cycle-invariance was slow for high frequency cycling.On a etudie la reduction du NO par le CO sur un catalyseur Pt/AI,O, a l'aide d'une technique de cyclage force de la concentration dans un reacteur de recyclage isotherme a 485 K. Les conversions moyennes dans le temps montrent un comportement de resonance avec I'augmentation de la frequence. Lors du recyclage de la concentration d'alimentation en opposition de phase, on a obtenu une conversion maximale du NO moyennee dans le temps de 78%, comparativement a une conversion de 3,8% en regime permanent. L'effet de I'angle de phase entre les cycles d'alimentation du NO et du CO a ete etudie. On peut ameliorer les conversions en diminuant I'avance de phase du NO en-dessous de 180". La convergence vers f'invariance de cycle est lente pour le cyclage a haute frequence.Keywords: NO reduction by CO, forced oscillations, forced composition cycling.he three-way catalyst currently used in automobile cat-

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Section: Transient Responsesupporting

confidence: 91%

Transient and resonant behavior for no reduction by CO over a Pt/Al₂O₃ catalyst during forced composition cycling

Sadhankar

Lynch

1996

Can J Chem Eng

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“… a Content of metal cobalt and rhodium in the reduced catalysts. b The area ratio of peak Ι and peak II c Metal dispersion calculated from CO chemisorption with the assumption that 0.7 CO molecules are adsorbed per surface metal atom d d p particle size calculated using the equation , V m = 13.78 × 10 –3 nm 3 for Rh, a m = 7.58 × 10 –2 nm 2 from CO-TPD results …”

Section: Resultsmentioning

confidence: 99%

Mutual Tailored Bimetallic Rh–Co Supported on La Modified SiO₂ for Direct Ethanol Synthesis from Syngas

Zhong

Wang

Guo

et al. 2019

Ind. Eng. Chem. Res.

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In this work, Rh–Co/La2O3–SiO2 showed excellent selectivity to ethanol for direct ethanol synthesis from syngas. The best catalyst exhibited 42.8% selectivity to ethanol with CO conversion of 12.3% and in 145 h’ running maintained stable at 553 K, 3 MPa and GHSV of 3900 mL (gcat h)−1. The investigate results indicated that the interaction of cobalt denoting electron to rhodium adjusted the amounts of carbon monoxide adsorbed associatively and dissociatively, and maybe created a new active site pair of Rh0/Coδ+ for generating ethanol. Moreover, the mutually doping effect could dilute Co and Rh atoms in Rh–Co nanoparticles (NPs), which effectively suppressed the formation of C2+H and C3+OH, and thus led to the high ethanol selectivity and good anticoking property assisting with the carbon eliminating effect of La2O3. Owing to the high dispersion of Rh–Co NPs, the catalyst showed good activity and high resistance to sintering.

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“…The CO chemisorption method has been used to determine the Pt dispersion and, as a ratio of chemisorbed CO to surface Pt atoms (CO/Pt s ), 0.7 has been frequently used for the purpose. ,, Actually, CO/Pt s ratios from 0.7 to 1.0 are observed for the supported Pt particles with H/Pt ratios higher than 0.25, depending on particle sizes and the type of oxide supports. − In contrast, larger Pt particles with H/Pt ratios below 0.25 show small CO/Pt s ratios (∼0.48) . Apart from oxide supports, Cheah et al have reported that the carbon-supported Pt nanoparticles with a diameter of 2.7 nm (H/Pt s ratio is 0.72) show a CO/Pt s ratio of 1 .…”

Section: Resultsmentioning

confidence: 99%

Fine Dispersion of Pt_4–5 Subnanoclusters and Pt Single Atoms over Porous Carbon Supports and Their Structural Analyses with X-ray Absorption Spectroscopy

et al. 2017

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We demonstrate the fine dispersion of Pt4–5 subnanoclusters or Pt single atoms on two types of porous carbon supports, Ketjen black (KB) and zeolite-templated carbon (ZTC). The loading amount of Pt4–5 subnanoclusters reached as much as ca. 4 and 13 wt % for KB and ZTC, respectively. For the fine dispersion of Pt subnanoclusters, simply filling an organoplatinum complex, (COD)PtMe2, as a Pt precursor into the micropores is found to be crucial to prevent agglomeration or sintering of Pt subnanoclusters. Moreover, it is possible to disperse Pt single atoms on ZTC, simply by decreasing the Pt loading amount down to ca. 0.9 wt %, owing to some stabilization effect by oxygen-containing functional groups. The detailed structural insights into the supported Pt subnanoclusters and Pt single atoms were analyzed by X-ray absorption spectroscopy (XAS). Extended X-ray absorption fine structure (EXAFS) analysis for Pt subnanoclusters reveals that the Pt–Pt bond is contracting to a large extent (∼2.8%) relative to balk values, and upon hydrogen chemisorption, the bond elongates more than the reported values for the 1.0 nm sized Pt nanoparticles.

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Influence of ceria on the interaction of CO and NO with highly dispersed Pt and Rh

Cited by 101 publications

References 17 publications

Transient and resonant behavior for no reduction by CO over a Pt/Al₂O₃ catalyst during forced composition cycling

Transient and resonant behavior for no reduction by CO over a Pt/Al₂O₃ catalyst during forced composition cycling

Mutual Tailored Bimetallic Rh–Co Supported on La Modified SiO₂ for Direct Ethanol Synthesis from Syngas

Fine Dispersion of Pt_4–5 Subnanoclusters and Pt Single Atoms over Porous Carbon Supports and Their Structural Analyses with X-ray Absorption Spectroscopy

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Influence of ceria on the interaction of CO and NO with highly dispersed Pt and Rh

Cited by 101 publications

References 17 publications

Transient and resonant behavior for no reduction by CO over a Pt/Al2O3 catalyst during forced composition cycling

Transient and resonant behavior for no reduction by CO over a Pt/Al2O3 catalyst during forced composition cycling

Mutual Tailored Bimetallic Rh–Co Supported on La Modified SiO2 for Direct Ethanol Synthesis from Syngas

Fine Dispersion of Pt4–5 Subnanoclusters and Pt Single Atoms over Porous Carbon Supports and Their Structural Analyses with X-ray Absorption Spectroscopy

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About

Transient and resonant behavior for no reduction by CO over a Pt/Al₂O₃ catalyst during forced composition cycling

Transient and resonant behavior for no reduction by CO over a Pt/Al₂O₃ catalyst during forced composition cycling

Mutual Tailored Bimetallic Rh–Co Supported on La Modified SiO₂ for Direct Ethanol Synthesis from Syngas

Fine Dispersion of Pt_4–5 Subnanoclusters and Pt Single Atoms over Porous Carbon Supports and Their Structural Analyses with X-ray Absorption Spectroscopy