94 Catalysts(催化剂) increase the rate of chemical reactions a third way to increase the rate of a reaction is to add a catalyst, which is any substance that increases the rate of a chemical reaction by lowing its activation energy. The catalyst may participate as a reactant, but it is then regenerated as a product Uncatalyzed rea reaction 20 H O.+2H.o+B 2Br +2H Reaction pathway9.4 Catalysts (催化剂) increase the rate of chemical reactions • A third way to increase the rate of a reaction is to add a catalyst, which is any substance that increases the rate of a chemical reaction by lowing its activation energy. The catalyst may participate as a reactant, but it is then regenerated as a product