• alumina
• ball-milling
• catalyst characterization
• catalyst synthesis
• CO chemisorption
• diffusion limitations
• heterogeneous catalysis
• incipient wetness impregnation
• kinetic model
• mercury porosimetry
• modeling
• monolithic reactor
• nitrogen physisorption
• palladium
• platinum
• simulation
• testing
• washcoat
• washcoat thickness
• water inhibition
• XRD

Aim of the study is to analyze the total methane oxidation on supported metal catalysts in monolithic reactors for exhaust gas aftertreatment systems.
Three different catalytic systems are compared: two monometallic, Pd/alumina and Pt/alumina, and one bimetallic, Pd-Pt/alumina.
The work ranges from synthesis to characterization of the catalysts, from testing under various conditions to modeling and simulation.
The catalysts powders are prepared by incipient wetness impregnation (IWI), which are subsequently ball-milled in order to obtain the slurry needed for the washcoating of the monoliths.
The physical and chemical properties of the systems are investigated through several characterization techniques, namely XRD analysis, CO chemisorption, nitrogen physisorption, mercury porosimetry and light microscope.
The performances of the monolithic structures are tested under different conditions, with dedicated focus on the effect of operating pressure and water content in the exhaust gas on the reaction conversion. Moreover, further tests are performed aiming at investigating the presence of diffusion limitations in the monolithic systems that could affect the overall reaction rate.
Furthermore, these systems are modeled by chosing both diffusion models for characterizing the transport phenomena and reaction rate expressions for determining the kinetic on the noble metal species. Global and microkinetic models are employeed.
Finally, the effect of pressure on the catalytic performance is simulated by means of the software DETCHEM. This step allows the validation of the assumed models.