Heats of Adsorption of Linear NO Species on a Pt/Al2O3 Catalyst Using in Situ Infrared Spectroscopy under Adsorption Equilibrium

Bourane, Abdennour; Dulaurent, Olivier; Salasc, S.; Sarda, Ch.; Bouly, Christophe; Bianchi, Daniel

doi:10.1006/jcat.2001.3361

Cited by 41 publications

(23 citation statements)

References 59 publications

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“…associated with the presence of these nitrate species [8]. Additionally, a weak band is observed to grow in for both samples at 1415-1428 cm -1 , which can be attributed to a linear nitrite [8,41], while other weak bands at ~1790 and ~1695 cm -1 likely correspond to linear NO species present on defect and terrace sites of Pt particles [43]. A negative band which arises at ca.…”

Section: Drifts Measurementsmentioning

confidence: 89%

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Rico-Pérez

Bueno‐López

Kim

et al. 2015

Applied Catalysis B: Environmental

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Model Pt/Ce0.9Pr0.1O2 and Pt/CeO2 NOx storage-reduction catalysts were prepared via nitrate calcination, co-precipitation and carbon-templating routes.Raman spectroscopic data obtained on the catalysts indicated that the introduction of praseodymium into the ceria lattice increased the concentration of defect sites (vacancies), arising from the higher reducibility of the Pr 4+ cation compared to Ce 4+ . For the Pr-promoted samples, H2-TPR profiles contained high temperature bulk reduction peaks which were less pronounced compared with their ceria analogs, indicating that the presence of praseodymium enhances oxygen mobility due to the creation of lattice defects. Under lean-rich cycling conditions, the cycle-averaged NOx conversion of the Pt/Ce0.9Pr0.1O2samples was in each case substantially higher than that of the Pt/CeO2 analog, amounting to a difference of 10-15% in the absolute NOx conversion in some cases. According to DRIFTS data, a double role can be assigned to Pr doping; on the one hand, Pr accelerates the oxidation of adsorbed NOx species during the lean periods. On the other hand, Pr doping destabilizes the adsorbed NOx species during the rich periods, and the kinetics of nitrate decomposition are faster on Pt/Ce0.9Pr0.1O2, leading to improved catalyst regeneration. These results suggest that ceria-based mixed oxides incorporating Pr are promising materials for NOx storage-reduction catalysts intended for low temperature operation.

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Section: Drifts Measurementsmentioning

confidence: 89%

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Rico-Pérez

Bueno‐López

Kim

et al. 2015

Applied Catalysis B: Environmental

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“…One exception here is the mechanism of Krähnert et al and this is one of the reasons why this mechanism has been used in our work. In literature NO adsorption on platinum is generally assumed to be a nonactivated process [10][11][12]. In contrast to this previous work Krähnert assumed an activated NO adsorption and fitted a value of 63.5 kJ mol -1 for the activation energy.…”

Section: Adaptation Of the Literature Mechanismmentioning

confidence: 94%

NH3-Slip Catalysts: Experiments Versus Mechanistic Modelling

et al. 2009

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“…A weak band at 1618 cm )1 can be assigned to NO adsorbed on Pt [32][33][34], although a bridging nitrate species cannot be excluded [26,27]. Bands at 1423 and 1356 cm )1 are probably due to NO adsorbed on SiO 2 in the form of nitrites [29,30,35].…”

Section: Adsorption Of No and Nomentioning

confidence: 94%

A kinetic and DRIFTS study of supported Pt catalysts for NO oxidation

Toops

Graham

et al. 2006

Catal Lett

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NO oxidation was studied over Pt/CeO 2 and Pt/SiO 2 catalysts. Apparent activation energies (E a ) of 31.4 and 40.6 kJ/mole were determined for Pt/CeO 2 and Pt/SiO 2 , respectively, while reaction orders for NO and O 2 were fractional and positive for both catalysts. Pre-treatment of the catalysts with SO 2 caused a decrease in the E a values, while the reaction orders were only slightly changed. In situ DRIFTS measurements indicated that high concentrations of nitrate species were formed on the surface of Pt/CeO 2 during NO oxidation, while almost no surface species could be detected on Pt/SiO 2 . The addition of SO 2 resulted in the formation of a highly stable sulfate at the expense of nitrate species and caused an irreversible loss of catalytic activity for Pt/CeO 2 .

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Heats of Adsorption of Linear NO Species on a Pt/Al2O3 Catalyst Using in Situ Infrared Spectroscopy under Adsorption Equilibrium

Cited by 41 publications

References 59 publications

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

Pt/Ce Pr1−O2 (x= 1 or 0.9) NO storage–reduction (NSR) catalysts

NH3-Slip Catalysts: Experiments Versus Mechanistic Modelling

A kinetic and DRIFTS study of supported Pt catalysts for NO oxidation

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