Selective gas adsorption or chemisorption

Measurements can be made either statically or dynamically and selective gases like CO (or H2) can be used. In the static experiment, a known amount of gas is added to a known amount of metal catalyst. Each gas molecule takes up a specific area on the metal surface (typically the gas is not adsorbed on the inert support surface). In the dynamic experiment, gas is pulsed over a catalyst. The amount of gas remaining in the pulse after contact with the metal is measured and, as before, the gas on the metal surface is calculated by difference to estimate the surface area available for catalysis. 

Selective adsorption results before and after a reaction can indicate the loss in surface area due either (1) to poisoning of the metal surface or (2) to reaction of the metal to form non-catalytic surafce layers (e.g. the formation of support oxide 

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