Surface Areas by Selective Chemisorption

In the pulse techniquea known amount of catalyst is placed in a flow reactor under a stream of nitrogen or argon. Measured pulses of hydrogen are then introduced into the carrier gas stream and passed through the catalyst bed. The amount of hydrogen not adsorbed is measured by on-line gas chromatography as depicted in Fig. 2.9. Subsequent pulses are introduced until no further 

The dissolution of hydrogen in palladium to form a- and (i-phase palladium hydrides has been assumed to present problems in determining the surface area of palladium catalysts by hydrogen chemisorption, but under normal chemisorption conditions this is probably not a factor. The a-phase Pd-H forms initially by the migration of hydrogen atoms from the surface into the interstitial volume of the palladium crystals. Hydrogen pressures near atmospheric are 

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