Heterogeneous Catalysts

Heterogeneous catalysis, as used in chemistry, is catalysis in which the phases of the catalysts and the reactants or products are different. In contrast, in homogeneous catalysis, the catalyst, reactants, and products are all present in the same phase. Phase may distinguish between components that are solid, liquid, or gas, as well as immiscible mixes and regions where an interface is present. Typically, solid phase catalysts and gas phase reactants are used in heterogeneous catalysis. At the catalyst surface in this instance, a cycle of molecule adsorption, reaction, and desorption is taking place. The rate of reaction is influenced by the laws of thermodynamics, mass transfer, and heat transfer. Because it permits more rapid, large-scale manufacturing and the synthesis of selected products, heterogeneous catalysis is crucial.