[Marky_sparky]

Hey all,
    I was wondering if you could lend a hand... I will attempt to react H2O2 with either Ir/Al2O3 or Ag/Al2O3 and i was wondering when the H2O2 decomposes how much of the Ir or Ag will cause impurities in the products?
ie 2H2O2 --> 2H2O + O2 + heat + "some product caused by the catalyst"

MT

[Arkcon]

By definition, catalysts do not change in a reaction.  Furthermore, the metals iridium and silver, aren't very reactive, that is, they don't form many stable compounds.  Where did you expect the "catalyst products" to accumulate -- dissolved in water, or vaporized in the oxygen, those just aren't likely.  There's a change that a vigorous reaction might break up a friable catalyst bed, but that's not really a chemical reaction.

[Marky_sparky]

But when the catalyst degrades it won't contaminate the air around it... there won't be any Ir being shed off?  I know that the catalyst isn't part of the reaction but it will degrade into what... that is what i can't figure out!

Thanks MT

[ifuller]

I think what Arkcon was saying is that a catalyst should not degraded at all. If it is a true catalyst you should be left with the exact same amount of catalyst at the end of the reaction as you initially had. Why do you think the catalyst will degrade?

[Borek]

I think I know what Marky_sparky aims at.

Imagine you use MnO₂ as a catalyst when decomposing H₂O₂. MnO₂ is very effective at that - but it is powdered, so if the water foams powder can be removed from the solution itself. In a way it degrades. But whether it may happen depends on the catalyst and its form. Note, that just because catalyst was dispersed and is no longer in the reaction vessel, doesn't mean its amount changed.