I have seen in literature that metal oxides play the role of catalysts in different reactions/processes. What is the reason that the metal oxides can act as catalysts?
In my opinion, it is related to the bandgap of metal oxide. When the photon comes, the electron of the specific type can be excited, and therefore the the electron owner have the ability to oxidize water or organic materials.
Normally, we have acid-base and oxidation-reduction reactions. For the red-ox reactions, the transition metal oxides can have electrons d or f and empty orbitals ... and can create some liaison with the reactant. That's a simplest idea that you can start with heterogenous catalyst for red-ox reactions.