Could you describe your situation a bit more? You mention both platinum and palladium, are both metals present? Is pure oxygen or oxygen in air your poison suspect? How are you observing/quantifying the deactivation

I am working with supported palladium nanoparticles in oxidation reaction with 35 mL/min O2 at 363 K, I have observed the deactivation by catalytic results. and I read in the litertautre that the deactivation of platinum comes from posison of platinum so the resistance of palladium from oxygen posion is also high

Dear Baraa,

You are working on palladium nanoparticules supported on a support , what are the reactifs of your reaction ? (give me more detail please)

Now, you compare your experimental results with the literature data concerning platinum catalysts, I supposed, it’s the same support and the same reaction (with same conditions: oxygen flow=35mL/min at 90°C). You cannot get great conclusions!! because the catalytic properties of the two elements (Pd and Pt) are doubtless differents.

Concerning your sample based on palladium,

your curve..........conversion=F(time)

probably indicates an important deactivation of catalyst, that means, that your reaction is an oxidative-dehydrogenation that produces hydrogen and/or condensation of the coke.

If your reaction produces H2 (as main product): mean that the saturation of the catalytic surface was caused by the adsorption of your reactif and desorption of H2 , resulting a total reduction of actives sites and saturation of the surface due probably to formation of coke.

If your reaction produces H2O: the presence of water is an inhibitory effect on your palladium catalysts, this phenomenon is explained by the dissociative adsorption of water on the adsorption sites resulting in the fall of catalytic performance.