Short answers, pulled from the story.
Catalysis is the increase in rate of a chemical reaction due to an added substance known as a catalyst. The catalyst is not consumed by the reaction and remains unchanged afterward, so a very small amount often suffices when it recycles quickly.
A catalyst provides an alternative reaction mechanism with a lower activation energy than the uncatalyzed pathway, so more molecular collisions reach the transition state. The original slower mechanism still remains possible, so the total rate can only increase in the catalyst's presence and never decrease.
The concept of catalysis was invented by chemist Elizabeth Fulhame, described in a 1794 book based on her novel work in oxidation-reduction reactions. She worked with water rather than metals and predated Jons Jakob Berzelius, who used the term catalysis in 1835.
Homogeneous catalysis has its components dispersed in the same phase as the reactants, usually gaseous or liquid, while heterogeneous catalysis has the reaction components in different phases. Enzymes and other biocatalysts are often considered a third category.
A catalyst does not change the chemical equilibrium because it leaves the ratio of forward and reverse reaction rates unaffected, as required by the second law of thermodynamics. A catalyst that shifted equilibrium would behave like a perpetual motion machine, contradicting the laws of thermodynamics.
Estimates are that 90 percent of all commercially produced chemical products involve catalysts at some stage of their manufacture. In 2005, catalytic processes generated about 900 billion dollars in products worldwide, spanning petroleum refining, ammonia production, and bulk chemicals.
The Nobel Prize in Chemistry 2021 was awarded jointly to Benjamin List and David W.C. MacMillan for the development of asymmetric organocatalysis. Organocatalysis uses small organic molecules without metals, often relying on noncovalent interactions such as hydrogen bonding.