In other words, if our reactants are in a gas state or liquid state then our catalysts are in a solid state. Now, when we're dealing with heterogeneous catalysts, namely Salad catalysts, this is what happens. Our reactants absorb momentarily or bind to the catalyst which weaken the bonds, decreasing activation energy which in turn increases the reaction rate. So let's look at the following uncategorized reaction. BR two reacts with C two h four to produce C two H two BR two. Now, this by itself is a very slow occurring reaction.