There, in your mouth, there is a catalyst at work, that accelerates the rate of digestion of the food you eat. It has a pretty name called ‘ptyalin‘. Without it, the starch in your food would take, I don’t know how long, to get hydrolyzed to glucose. This catalyst resides in the human saliva. It is one of the many different enzymes that are present in our bodies. Enzymes are nature’s catalysts.
Coming to industrial catalysts, a catalyst increases (accelerates) the rate of reaction without affecting the equilibrium. It does take part in the reaction, it forms some kind of a complex with the reactants, but is regenerated again.
(Image: Industrial Catalysis: A Practical Approach, Second Edition. Jens Hagen)
You can read Industrial Catalysis: A Practical Approach, Second Edition, by Jens Hagen. Excellent book.
The books says that there is still no fundamental theory of catalysis. To date there has been no standard book that deals equally with hetero and homo catalysis, as well as industrial aspects thereof.
The book also says that apart from accelerating reactions, catalysts have another important property, they can influence the selectivity of chemical reactions. How? We’ll see that in other posts.
In general, catalysts are used for industrial synthesis, in biological applications and environmental protection. Industrial applications include the chemical industry (dyes and pigments, agrochem, pharmaceuticals, fine chemicals etc.) and the petroleum industry.
Talking about money, market of heterogeneous catalysts is 80 percent while that for homogeneous catalysts is 20 percent. Why? Well, as the definition of heterogeneous catalysts goes, they can be easily separated from the reaction mixture.