Chemisorption
Strong adsorption in which actual chemical bonds form between the adsorbate and the surface.
Formula / equation
ΔH ≈ −80 to −400 kJ/mol
Unit
kJ/mol
In depth
Chemisorption is highly specific to particular adsorbate–surface pairs, forms only a single layer, and is often irreversible. It frequently requires activation energy, so it increases with temperature — the opposite of physisorption. It is the step that activates reactant molecules in catalysis.
Examples in the real world
Hydrogen dissociating into atoms on a nickel surface, which is what makes catalytic hydrogenation possible.