Question
Question: What role does adsorption play in heterogeneous catalysis?...
What role does adsorption play in heterogeneous catalysis?
Solution
As we know that adsorption is a very important concept of surface chemistry. Adsorption is the process in which there is deposition of molecular species onto the surface. Catalysis is the process of increasing the rate of the reaction.
Complete step by step answer:
It is very important for us to know about the term heterogeneous catalysis before proceeding to the answer of the question. Heterogeneous catalysis is a type of catalysis in which the phase of the catalyst used in the catalysis process differs from the reactant or the products of the reaction .
Generally the reactants of the heterogeneous catalysis are in gaseous state and the catalysts are solids. The gaseous molecules get absorbed in the surface of the catalyst ,that means the gaseous molecules get deposited in the solid surface of the catalyst due to which the concentration of the reactant increases which in turn increases the rate of reaction. The catalyst does not undergo any change itself. In other words we can say that due to the adsorption , the gaseous reactant molecules get a platform to react with the catalyst and increase the rate of reaction. The products formed in the reaction are continuously released and desorbed from the surface so that it can accommodate more reacting species. From this discussion and explanation it is clear to us that adsorption plays an very important role in heterogeneous catalysis.
Additional information:
Catalyst used in a chemical reaction does not alter the Gibbs free energy . It just increases the rate of reaction by just lowering the activation energy of the reaction.
Note:
It is important to remember that adsorption is a surface phenomenon, adsorption decreases the entropy . Heat is released in an adsorption process , so it is an exothermic reaction. In heterogeneous catalysis the phase of catalyst and the reactant or product are different.