Why is there a Catalyst used in the Contact Process? What even is it?

-This is to only Increase the Rate of Reaction of SO₂ + O₂ ⇌2SO₃ -It is Vanadium Pentoxide, V₂O₅ -Without it, it would make the Costs for Temperature [Has to be Higher to make the Rate Faster] and Pressure [In case the Temperature gets too High for the Position