why is vanadium pentoxide preferred  over platinised asbestos in the contact process?

Hi,

Ideally, platinum is a more efficient catalyst than vanadium pentoxide. But it is more expensive and it also gets poisoned by impurities like arsenic (III) oxide.On the other hand, vanadium pentoxide though less efficient is cheaper and not affected by impurities. Thus, vanadium pentaoxide is preferred over platinised asbestos.

 

Hope this answers your question.

Best Wishes!