Question

What is a catalytic promoter?

Answer 1

Hint: Catalysts themselves are chemical agents that help enhance the kinetics of a reaction without getting consumed (the same amount of catalyst is recovered after the completion of reaction). A promoter is an additional substance that affects the catalyst and not the rate of the reaction directly.

Complete answer:
Reaction kinetics deals with the rate of formation of products or the rate of consumption of reaction. This tells us how fast the reactants are being transformed into products with a given set of reaction conditions.
Few reactions are thermodynamically feasible in nature but still take a long period of time to reach the completion stage. Even though the formation of products is energetically allowed (the products are more stable than the reactants) , the high activation energy needed to complete the reaction makes the process extremely slow.
Catalysts are compounds or elements that offer an alternative pathway of carrying out a reaction by making it go through a path that requires less activation energy thereby enhancing the reaction rates.
Catalysts promoters are chemical species that are added onto catalysts to increase their efficiency and enhance their performance. The promoter may bring slight changes in the structure or the active site of the catalyst to improve its properties.
Example: In the Haber’s process of ammonia synthesis, traces of Molybdenum are added on to the iron catalyst to improve its catalytic properties. Therefore Molybdenum acts as a catalyst promoter.

Note:
The catalytic promoter can only be used in the presence of or along with the catalyst in the reaction. The promoter itself has zero catalytic properties and is therefore incapable of altering the rate of the concerned reaction.