Doctor of Philosophy / Department of Chemical Engineering / Keith L. Hohn / Catalytic partial oxidation (CPO) has received considerable interest recently both as a way to utilize remote natural gas resources and to provide H[subscript]2 for a fuel cell. Studies on the reactions at lower temperatures and transient conditions were performed, which can provide insights on the mechanism of CPO at high reactions, particularly on the role of the chemical and physical state of the noble metal catalyst. In this work, ignition of methane CPO on Pt/Al[subscript]2O[subscript]3 and Rh/Al[subscript]2O[subscript]3 catalysts and methanol CPO on Pt/Al[subscript]2O[subscript]3 catalysts were studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The ignition mechanism study of CH4 on Pt/Al[subscript]2O[subscript]3 showed that oxygen mainly covers the surface until ignition. Competition between the two reactants is assumed. The heat of adsorption of oxygen is a key factor for ignition of the methane partial oxidation reaction on Pt/Al[subscript]2O[subscript]3. The ignition mechanism on Rh/Al[subscript]2O[subscript]3 was found to be different from Pt/Al[subscript]2O[subscript]3. The oxidation state of the catalyst changed significantly as the temperature was raised towards the ignition. An oxidized rhodium state, Rh[superscript]n+, progressively formed as the temperature was increased while Rh[superscript]0 decreased. In addition, a greater amount of Rh[supercript]n+ was found when the oxygen concentration in the feed was higher. From these results, it is hypothesized that ignition of methane CPO on Rh/Al[subscript]2O[subscript]3 is related to the accumulation of the Rh[superscript]n+ state. Dissociation adsorption of methanol occurs on both Al2O3 and Pt/Al[subscript]2O[subscript]3. It is suggested that formate was one of the important intermediates in the reaction pathway. Oxygen species play a key role in the formation of formate on the catalysts, and it also affects the product composition. Formate mainly decomposed into CO, which is the dominant source for CO[subscript]2 production in the reactions at higher temperatures.

L'hydrogène est envisagé comme vecteur énergétique pour le futur. En effet, son utilisation par oxydation dans les piles à combustible ne produit que de la vapeur d'eau et permet la production d'électricité et de chaleur. L'oxydation partielle des hydrocarbures, réaction exothermique, peut être une alternative ou un complément au vaporeformage (endothermique) pour la génération d'hydrogène. L'intérêt du propane, par rapport au méthane, est qu'il se liquéfie à une pression relativement faible. L'objectif de ce travail est l'étude cinétique de l'oxydation partielle catalytique du propane. C'est une réaction complexe : son mécanisme comporte des réactions catalytiques de surface couplées à des réactions en phase gazeuse par l'intermédiaire de radicaux. La réaction a été étudiée dans un réacteur auto-agité catalytique. Dans un premier temps une étude expérimentale a été réalisée sans catalyseur. Un mécanisme homogène a pu ainsi être validé. Ensuite, cette même réaction a été étudiée en présence de pastilles d'oxyde de cérium. Un mécanisme hétérogène a été écrit en utilisant le formalisme d'Eley-Rideal et celui de Langmuir-Hinshelwood. Les données cinétiques ont été estimées selon une méthode originale basée sur la théorie de Benson. En comparant les résultats expérimentaux et ceux issus de la simulation (effectués avec Chemkin®/Chemkin Surface®), un mécanisme hétéro-homogène a été validé sur un large domaine de conditions opératoires / Hydrogen is proposed as an energy vector for the future. Indeed, its energetic use by oxidation in fuel cells produces water vapor only. The partial oxidation of hydrocarbons, an exothermic reaction, can be an alternative or a complement to the steam cracking (endothermic) for hydrogen generation. Propane can be an interesting hydrocarbon for hydrogen production since it can be easily stored in liquid phase and distributed. The aim of this work is the kinetic study of the catalytic partial oxidation of propane. The reaction is complex: catalytic reactions are coupled to reactions in gas phase by the intermediary of radicals. The reaction was studied in a catalytic jet stirred reactor. At first, an experimental study was carried out without a catalyst. A homogeneous mechanism could be validated. Afterwards, this same reaction has been studied in presence of cerium oxide pellets. A heterogeneous mechanism was written using the formalism of Eley-Rideal and that of Langmuir-Hinshelwood. The kinetics parameters are estimated by methods derivated from Benson's techniques. Comparing experimental results and those from the simulation (carried out by Chemkin®/Chemkin Surface®), a hetero-homogeneous mechanism was validated in our experimental conditions