The catalyst activity depends on both the availability
of Ni as well as on the Ni-support interaction. The
phenomenon of Ni migration into the clay sheets and
the Ni existence within the ditrigonal holes result in
making part of the metal impregnated inactive and/or
inaccessible for the reaction.
Favourable for the catalytic activity is Ni located
near the existing acid sites of the support and forming
larger interlayer patches up to a size that most of the
micropores remain accessible to benzene molecules.
Pretreating the support by Al3C ion-exchange prior
to Ni impregnation prevents a large portion of Ni introduced
from migrating into the clay lattice, while it
modifies the clay surface in a way that more acid sites
seem to be created in addition to those existing due to
the pillars.
The most active catalyst resulted from Al3C ionexchange
of the pillared montmorillonite and subsequent
introduction of 12% (w/w) Ni, sufficient to form
metal aggregates with less pronounced carrier effect