Zeolite catalyst or shape selective catalyst:
Zeolites are small porous alumina silicates. Their general formula is M3 [(Al2O3)x (SiO2)y]3 n H2O where n is the oxidation state of metal (M).
Example:
Zeolite catalyst ZSM-5 is used in the conversion of alcohol into petrol (gasoline). The dehydration of alcohol takes place on pores of zeolite and forms a mixture of hydrocarbons.