Catalysts are substances that speed up the rate of a chemical reaction. It is important to know that reacting species must first possess a minimum amount of energy equal to the activation energy for the reaction to proceed. The catalyst works in a way that lowers the activation energy required for the reaction to proceed. In this way, the reaction occurs at a faster rate than without a catalyst. Catalysts do not react with the chemical species in the reaction, thus, they are not consumed. However, over time, catalysts tend to degrade and their function is also reduced. When this happens, new catalysts replace the poisoned ones. Catalysts are widely used today since they bring an increase in the production rate of commercial chemicals.