Decomposition of nitric oxide on platinum

Amirnazmi, Ali

doi:10.1016/0021-9517(75)90305-x

Cited by 70 publications

(26 citation statements)

References 4 publications

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“…Therefore, no steady-state activity for NO decomposition will be displayed by platinum surfaces at moderate temperatures. This conclusion is in accordance with the literature [23,24].…”

Section: Adsorption and Reactivity Of No On Platinumsupporting

confidence: 94%

The interaction of nitric oxide with platinum and platinum-silver catalysts

Jong¹,

Meima

Geus

1982

Applications of Surface Science

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The interaction of NO with Pt/SiO 2 and PtAg/Si02 catalysts is investigated by infrared spectroscopy, volumetric chemisorption and mass spectrometry. Room temperature adsorption of NO on the reduced Pt/Si02 catalyst mainly leads to molecular adsorption, accompanied by a small N2 production. Infrared spectra reveal absorption bands at 1780 and 1600 cm j, ascribed to the stretching vibrations of linearly and bridged bonded NO species, respectively. Furthermore, a weak band at 1935 cm 'is observed. This high-frequency band is strongly enhanced when NO is dosed at elevated temperatures and is attributed to NO bound to Pt sites in the neighbourhood of adsorbed oxygen atoms. Reaction of NO with Pt/SiO2 at 400°Cleads to a limited dissociation of NO, producing N2 in the gas phase and leaving oxygen atoms to remain on the catalyst surface. With the PtAg/Si02 catalysts the 1600 cm band is absent, while the activity for NO dissociation has been lowered as compared to Pt/Si02. Alloying of Pt with Ag diminishes the amount of bridged bonded species which seem to precede dissociation, whereas linearly bonded species desorb molecularly at high temperatures. Investigations of the catalysts after oxidation at 400°C in 1 atm 02 show the adsorption of NO to be weaker and non-dissociative even at 400°C.

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“…Therefore, no steady-state activity for NO decomposition will be displayed by platinum surfaces at moderate temperatures. This conclusion is in accordance with the literature [23,24].…”

Section: Adsorption and Reactivity Of No On Platinumsupporting

confidence: 94%

The interaction of nitric oxide with platinum and platinum-silver catalysts

Jong¹,

Meima

Geus

1982

Applications of Surface Science

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“…This reaction is especially prevalent at higher temperatures and tends to set the oxygen surface coverage. 5,38 The surface N* and O* that form can subsequently recombine with other N* and O* to form N 2 and O 2 , respectively, which readily desorb from surface. The N* and O* adatoms can also recombine to form NO* on the surface.…”

Section: Reaction Mechanismmentioning

confidence: 99%

First-Principles-Based Kinetic Monte Carlo Simulation of Nitric Oxide Reduction over Platinum Nanoparticles under Lean-Burn Conditions

Mei

Neurock

2010

Ind. Eng. Chem. Res.

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The kinetics for NO reduction over supported platinum under lean condition were investigated by firstprinciples-based kinetic Monte Carlo simulation over three-dimensional Pt nanoparticles. Model platinum nanoparticles with diameters ranging from 2.3 to 4.6 nm were constructed using a truncated octahedral cluster consisting of a two (100) facets and eight (111) facets. First-principles density functional theory (DFT) calculations were used to calculate the intrinsic kinetic parameters including the binding energies for all of the surface intermediates as well as the activation barriers and reaction energies that comprise the reaction mechanism over the (100) and (111) facets, as well as the (111)/(100) edge sites on the three-dimensional nanoparticle. Both intra-and inter-facet diffusion of adsorbates were included to model surface diffusion effects over the particle surface. The simulation results show that under lean conditions where there is excess oxygen, NO reduction to N 2 occurs solely on the (100) facets. The oxidation of NO to NO 2 , while much more favored on the (111) facets, can occur on both (100) and (111) facets. Only small amounts of N 2 O form over the (100) facets. The simulated apparent activation energies for N 2 and NO 2 formation over the entire particle are 45 and 42 kJ/mol, respectively. The latter is in agreement with experimentally measured value of 39 kJ/mol [Mulla, S. S., et al., Catal. Lett. 2005, 100, 267]. The effects of particle size on the activities of NO reduction to N 2 and NO oxidation to NO 2 depend upon the ratios of exposed surface sites. For the threedimensional model Pt nanoparticles examined here, the fractions of the (100) terrace sites are similar while the fraction of the (111) terrace sites increases with increasing particle size. As a result, the activity for NO reduction is somewhat insensitive to the particle size which symmetrically increases the numbers of (111) and (100) facets as the size increases. NO reduction, however, increases much more dramatically when the number of the (100) sites increases over the (111) sites. NO oxidation activity, on the other hand, appears to increase with increasing particle size regardless of the symmetry or shape of the particle as the reaction occurs predominantly over the (111) sites but can also take place on the (100) terrace sites. The structure insensitivity for NO oxidation is consistent with experimental results.

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“…There is clearly a need to develop alternative processes, most probably catalytic, which will reduce nitric oxide emissions without relying on noble metal catalysts. In addition to these problems, the catalytic converters currently in use will not operate in a feedstream that contains an excess of oxygen (3). This limitation renders even noble metal catalytic systems unable to reduce nitric oxide emissions from diesel engines, nonnuclear power plants, or industrial furnaces.…”

Section: Introductionmentioning

confidence: 99%

Reduction of nitric oxide with carbon monoxide on the Rh(100) single-crystal surface

HENDERSHOT

1986

Journal of Catalysis

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Decomposition of nitric oxide on platinum

Cited by 70 publications

References 4 publications

The interaction of nitric oxide with platinum and platinum-silver catalysts

The interaction of nitric oxide with platinum and platinum-silver catalysts

First-Principles-Based Kinetic Monte Carlo Simulation of Nitric Oxide Reduction over Platinum Nanoparticles under Lean-Burn Conditions

Reduction of nitric oxide with carbon monoxide on the Rh(100) single-crystal surface

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