A catalyst increases the rate of reaction in a slightly unconventional way from other means of increasing reaction rate. The role of a catalyst is to lower the activation energy so that a greater proportion of the particles have enough energy to react. A catalyst can lower the activation energy for a reaction by:
- Orienting the reacting particles in such a process that successful collisions are more likely
- Reacting with the reactants to form an intermediate that needs lower energy to form the product
Some metals, for example, copper platinum, and iron can act as catalysts in certain reactions. In our own bodies, we have enzymes that are catalysts, which help to speed up biological reactions. Catalysts generally react with one or more of the reactants to form a chemical intermediate, which then reacts to form the final product. The chemical intermediate is called the activated complex.