*2.3. Poisoning*

Catalytic poisoning is a result of the strong chemisorption of reactants, products or impurities on sites that would otherwise be capable of catalysis. In essence, the poisoning ability of a particular species is related to the strength of its chemisorption to the catalysis relative to the other reactants that are competing for the catalytic active sites. The poisoning has two deactivating effects; a poison physically blocks the active sites from receiving additional reactants, and a poison can alter the electronic or structural properties of the catalytic surface, rendering it partially or completely ineffective toward catalysis [62,63].

While there are several different poisons which have been reported in the literature that have shown to deactivate CO2 hydrogenation catalysts [64,65], we will focus on the two which are the most pervasive, namely water and carbonaceous deposits or coke.
