I don’t think they provide the energy, they change the required energy for a reaction to occur. My understanding is that is can happen due to the physical struc

I don’t think they provide the energy, they change the required energy for a reaction to occur. My understanding is that is can happen due to the physical structure of the catalyst changing the electronic configuration of the molecules being reacted. I think often instead of the two molecules coming into contact and reacting, the two molecules and the catalyst come into contact. It’s a whole different reaction, but the catalyst molecule doesn’t change its composition and is left unchanged after the reaction. I guess maybe a terrible analogy would be you’re trying to cross a flat field but there is a large group of animals, say, cows in the way. You’d never be able to get through the crowd of cows without exerting a lot of energy. Then suddenly a dog, catalyst, come over and starts shooing off the cows. Now the cows have moved out of the way and the flat field is clear. You can now make the journey while expending less energy. Hmm maybe someone else can explain it better!