Sr. Demiguel et al., EFFECT OF THE ADDITION OF ALKALI-METALS ON THE METALLIC PHASE OF PT AL2O3 CATALYSTS/, Catalysis letters, 32(3-4), 1995, pp. 281-291
The effect of the addition of alkali metals to Pt/Al2O3 catalysts for
dehydrogenation of paraffins was studied. Results can be interpreted i
n terms of different effects. Thus, the addition of alkali metals prod
uces a poisoning of the acid sites of the alumina support and a modifi
cation of the characteristics of the metallic phase. The latter effect
involves not only an increase of the Pt particles size, but also an e
lectronic modification of the metallic phase. These two effects are mo
re marked with alkali metals with higher ionic radius, such as K.