What is heterogeneous catalysis? Give an example.

Hint:Catalysis is a very important concept in the chemistry as catalysts though they themselves can govern the product despite not being changed at the end of the reaction. The process of governing the pace of the reaction by physical addition is catalysis and the process in which the catalyst is in a different physical state to the reactant is heterogeneous.

Complete step by step answer:
For the given question firstly we need to be aware of the term catalysis.
Catalysis can be termed as the process in which there is an imminent increase in the rate of a chemical reaction by the addition of a substance. These substances are termed as a catalyst. Catalysts have a feature that ultimately at the end of the reaction they are not consumed in the catalyzed reaction but can act repeatedly. Generally we add only very small amounts of catalyst as compared to the reacting components.
Now for the term of the heterogeneous catalysis, they are :
It is the type of catalysis in which the catalyst and the reactants are present in different phases. Thus we can say that the reaction in which the catalyst is in a different physical state to the reactants is called heterogeneous catalysis. And thus the catalyst which exists in different phases from the reactants is known as heterogeneous catalyst.
Example: Hydrogenation of unsaturated compounds catalysed by the transition metals like \[Ni,{\text{ }}Pd,{\text{ }}Pt\] .



Note:The process of the catalysis can be divided into the two types, heterogeneous or the homogeneous as per the state. In the commercial process the global demand for these catalysts as per the data in $2010$ was estimated at approximately \[US\$ 29.5{\text{ }}billion\] .