The thermal and photoassisted catalytic oxidation
of CO at metal oxide supported RuO
2
x
H
2
O was studied at
room temperature. Contrary to neat RuO
2
x
H
2
O the support-
ed catalysts suffer from fast deactivation attributed to strong
adsorption of the reaction product carbon dioxide. The latter
can be efficiently removed from the catalyst surface at ele-
vated temperatures. In some cases,
i.e
. for catalysts supported
with selected
n
-type semiconductors (TiO
2
,SnO
2
,WO
3
), effi-
cient CO
2
desorption and good, constant catalytic activity was
observed upon visible light irradiation. Under such conditions
the CO to CO
2
conversion observed for RuO
2
x
H
2
O
=
TiO
2
was nearly as good and stable as for the unsupported catalyst.
It is suggested that light absorption promotes carbon dioxide
desorption through positive charging of the catalyst surface