Who's ready to answer a riddle for upvote?

Guys, I've been throwing riddles into communities to see the brains on the platform. Kindly subscribe to my channel for more thrilling riddles. So here we go:

I am a compound.

I can be a catalyst and an oxidizing agent.

As a catalyst, I'm used in decomposition reaction.

If I normally attached to Potassium in redox reactions, then

Who Am I ?