Hello, Salim,
Catalysis is the name given to a chemical reaction in which something is done to the system in order to accelerate the reaction. It is a phenomenon, the overall process. A catalyst the thing/substance that is actually used to catalyze a reaction. A catalyst acts to reduce the activation energy of the reactants, thereby making it easier to proceed. Catalysis is the process in which a catalyst is used.
Bob

Robert S.
05/23/21
Salim A.
Thank you05/23/21