A series of manganese oxides loaded on an active alumina support was p
repared by mechanical mixing of a known amount of manganese carbonate
with calculated amounts of a finely powdered alumina preheated in air
at 450-degrees-C. The solids were heated in air at temperatures rangin
g between 400 and 1000-degrees-C. The amount of manganese, expressed a
s Mn2O3, was varied between 1.9 and 38 wt%. The surface properties nam
ely specific surface area (S(BET)), total pore volume (V(p)) and mean
pore radius (rBAR) were computed for the various supported solids from
nitrogen adsorption isotherms conducted at 77 K. The catalytic proper
ties were studied via following the kinetics of CO oxidation by O2 at
various temperatures between 100 and 300-degrees-C. The catalytic acti
vities of the various solids expressed as reaction rate constant (k) a
nd the reaction rate constant per unit area (kBAR), for Co oxidation r
eaction by O2 were found to increase progressively by increasing the a
mount of manganese present reaching maximum values at 15.2 wt% Mn2O3 t
hen remained unchanged by increasing the amount of manganese above thi
s limit. The apparent activation energies of CO oxidation reaction con
ducted over the various solids were found to be not much affected by t
he amount of manganese present, especially for the solids calcined at
temperatures greater-than-or-equal-to 500-degrees-C.