If you're a chemist and your specialty is catalysis, then you're usually looking for ways to speed up the rates of chemical reactions so you can change molecules to other molecules more efficiently. The results are new molecules for such things a effective medicines, useful plastics or synthetic fibers.
Catalysts are critical to change.
They make chemical reactions go faster, and they do so without undergoing permanent changes themselves. This characteristic allows catalysts to act over and over again and process huge amounts of material. A little bit of a catalyst goes a long way in bringing about a change. But as any chemist would tell you, there is often a price to pay. Many chemical reactions that convert materials to useful products also produce wastes that can be harmful to the environment and cause significant destruction, such as the hole in the ozone layer.