Catalyst Poisoning
The loss of catalytic activity caused by a substance binding irreversibly to the active sites.
Unit
Dimensionless
In depth
Poisons adsorb so strongly that the sites are permanently blocked, so even trace amounts can destroy a catalyst bed worth a great deal of money. Feedstocks are therefore purified rigorously before entering a catalytic reactor, and poisoning is often irreversible.
Examples in the real world
Lead poisoning a car's catalytic converter, which is why leaded petrol was withdrawn; sulfur poisoning the Haber catalyst.