Stannic oxide-titanium dioxide (SnO2–TiO2)
coupled semiconductor photocatalyst loaded with polyaniline (PANI), a conducting
polymer, possesses a high photocatalytic activity in oxidation of 1-octene to
1,2-epoxyoctane with aqueous hydrogen peroxide. The photocatalyst was prepared
by impregnation of SnO2
and followed by attachment of PANI onto a TiO2
powder to give sample PANI-SnO2–TiO2.
The electrical conductivity of the system becomes high in the presence of PANI.
Enhanced photocatalytic activity was observed in the case of PANI-SnO2–TiO2
compared to PANI-TiO2,
SnO2–TiO2,
and TiO2.
A higher photocatalytic activity in the oxidation of 1-octene on PANI-SnO2–TiO2
than SnO2–TiO2,
PANI-TiO2,
and TiO2
can be considered as an evidence of enhanced charge separation of PANI-SnO2–TiO2
photocatalyst as confirmed by photoluminescence spectroscopy. It suggests that
photoinjected electrons are tunneled from TiO2
to SnO2
and then to PANI in order to allow wider separation of excited carriers.