M. Ferrandon et al., Total oxidation catalysts based on manganese or copper oxides and platinumor palladium II: Activity, hydrothermal stability and sulphur resistance, APP CATAL A, 180(1-2), 1999, pp. 153-161
Deactivation of catalysts based on either manganese oxides, copper oxides,
platinum, palladium or combinations of these metal oxides and noble metals
supported on gamma-alumina was studied. The activity of the catalysts for t
he oxidation of carbon monoxide, naphthalene and methane, in a mixture rese
mbling the flue gases from wood combustion, was measured before and after e
xposure of the catalysts either to a temperature of 900 degrees C in the pr
esence of steam or to sulphur dioxide. Most of the mixed catalysts were mor
e resistant to hydrothermal and sulphur treatments than the catalysts with
a single active component. After the hydrothermal treatment the activity of
the MnOx catalyst was enhanced. When Pt is combined with MnOx or CuOx, the
loss of activity of Pt was decreased during the hydrothermal treatment. Al
so, the hydrotreated mixed MnOx-Pd and CuOx-Pd catalysts were more active t
han the treated Pd catalyst for the oxidation of methane. After sulphur tre
atment, the activities of the mixed MnOx-Pt (Pt: 0.05 mol%), MnOx-Pd and Cu
Ox-Pd catalysts were improved for the oxidation of carbon monoxide and naph
thalene. Among the catalysts studied, the MnOx-Pt, CuOx-Pt and CuOx-Pd cata
lysts, with a metal oxide and a noble metal loading of 10 and 0.1 mol%/gamm
a-alumina, respectively had the best combination of activity, thermal stabi
lity and resistance to sulphur treatment. (C) 1999 Elsevier Science B.V. Al
l rights reserved.