The influence of platinum concentration and particle size on the kinetics of propane oxidation over Pt/γ-alumina

K. Otto, Jean M. Andino, C. L. Parks

Research output: Contribution to journalArticle

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Abstract

For the regulation of automotive emissions it is of interest to understand the parameters that control the oxidation rates of different hydrocarbon species. Propane oxidation was selected as a model reaction for this investigation. Catalysts were prepared by multiple impregnation of γ-alumina with chloroplatinic acid. Concentrations ranged from 0.03 to 30 wt% Pt. The reaction took place in a recirculation batch reactor with an initial mixture of 10 Torr C3H8, 100 Torr O2, and 650 Torr Ar. The oxidation rate increased sixfold with increasing Pt concentration. When calculated per Pt surface atom, based on CO chemisorption, the rate increased by two orders of magnitude in the same Pt concentration range. The apparent activation energy remained unchanged at 22.1 kcal/mol within a standard deviation of ±3.4 kcal/mol. The increase in specific reaction rate with particle size was confirmed by sintering experiments. The rate increase reflects an increase in the preexponential factor. The results suggest that propane oxidation is expedited by a favorable ensemble of active Pt sites, which are more likely to form on larger crystallites. Kinetic parameters of propane and methane oxidation are compared. Theoretical site densities, derived from fundamental kinetics for common reaction mechanisms, are compared with the number of Pt surface atoms as measured by chemisorption.

Original languageEnglish
Pages (from-to)243-251
Number of pages9
JournalJournal of Catalysis
Volume131
Issue number1
DOIs
Publication statusPublished - 1991

Fingerprint

Propane
Aluminum Oxide
Platinum
propane
platinum
Alumina
aluminum oxides
Particle size
Oxidation
oxidation
Kinetics
kinetics
Chemisorption
chemisorption
Atoms
Methane
Batch reactors
Carbon Monoxide
Hydrocarbons
Crystallites

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology

Cite this

The influence of platinum concentration and particle size on the kinetics of propane oxidation over Pt/γ-alumina. / Otto, K.; Andino, Jean M.; Parks, C. L.

In: Journal of Catalysis, Vol. 131, No. 1, 1991, p. 243-251.

Research output: Contribution to journalArticle

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