An Overview of Some Basic Concepts in Catalysis

If we look at the entire reaction system as a black box, it seems that the catalyst simply lowers the activation energy. We now know that this is true in only a few cases. In most cases, the catalyst actually opens an alternative reaction pathway. This pathway is often more complicated, and includes several catalytic intermediates. However, the highest activation barrier in the catalytic pathway is still lower than that of the noncatalytic one. We also know that the catalyst does not and cannot change the thermodynamics, and that it catalyzes both the forward and reverse reactions (just as a pathway between mountains eases crossing in both directions). This means that the best catalyst for the reaction A + B C is also the best catalyst for the reaction 

C — A + B. Now that we have some background on the kinetics of various reaction types, let us examine some common qualitative concepts in catalysis. 

---