The catalytic performance of the catalysts based
on palladium supported on alumina can be
improved significantly by addition of metal oxides
of Ni, Co and mixed Co – Ce, Co-Mn oxides
whose effect has been attributed to the formation
of high dispersed well stabilized Pd or PdO
clusters on the support, thus increasing the
catalytic activity.
The close contact between Pd and oxides could
result in supply of more oxygen to Pd thus stabilizing
it on the support in form of PdO.
The activation after the thermal treatment is
observed for Pd/CoCe/Al2O3, and Pd/Ni/Al2O3
samples.
Remarkable deactivation proceeds when the
samples are modified with Mn - oxides
(Pd/Mn/Al2O3 and Pd/CoMn/Al2O3). The decrease
in the number of active centers might be due to
partial decoration of Pd from manganese oxide.