what are the examples of physisorption and chemisorption
Physisorption is the process of adsorption in which the accumulation of gas on the surface of a solid occurs on account of weak van der Waal’s forces. The adsorption of gases (like nitrogen, hydrogen etc) on the surface of adsorbents like charcoal at low temperatures is an example of physisorption.
Chemisorption is the process of adsorption in which the gas molecules or atoms are held to the surface by chemical bonds. The chemical bonds may be covalent or ionic in nature. Examples include adsorption of nitrogen or hydrogen on the surface of Fe catalyst.
The adsorption of hydrogen on the surface of Ni catalyst is an example of both physisorption and chemisorption. Dihydrogen is first adsorbed on nickel by van der Waals’ forces. Molecules of hydrogen then dissociate to form hydrogen atoms which are held on the surface by chemisorption.