Res. Chem. Intermed.
, Vol. 34, No. 4, pp. 331–337 (2008)
Koninklijke Brill NV, Leiden, 2008.
Also available online - www.brill.nl/rci
Synthesis and photocatalytic activity of TiO
ﬂuorine-modiﬁed with TiF
SHUAI YUAN, SHINICHI KAWASAKI, KOHSUKE MORI and
Division of Materials and Manufacturing Science, Graduate School of Engineering,
Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
Received 28 April 2007; accepted 31 August 2007
nanoparticles were synthesized by introducing TiF
as a ﬂuorine
source either before or after the sufﬁcient hydrolysis and condensation of Ti(OEt)
. The photocatalytic
activity of the ﬂuorine-modiﬁed catalysts was found to be greatly affected by the ﬂuorine position in
nanoparticles. When TiF
hydrolyzed with synchronization, the ﬂuorine tended
to be doped in the lattice. The formation of Ti
defects could result in charge recombination in
bulk and bring down the photocatalytic activity. In contrast, if TiF
was introduced after the sufﬁcient
hydrolysis and condensation of Ti(OEt)
, Ti–F bonds could exist mainly on the TiO
which not only prevented the growth of anatase crystals but also facilitated the transfer of organic
compounds from solution to catalyst surface by reducing the hydrophilic properties.
Keywords: Photocatalyst; titanium oxide; degradation; ﬂuorine modiﬁcation.
is a kind of semiconductor with suitable band gap and high stability against
nanoparticles show high activity in the photocatalytic degradation
of organic pollutants and toxicants [1, 2]. During the past decade, cations and
anions have been doped in TiO
to improve photocatalytic activity [3, 4]. In recent
years, the surface modiﬁcation has received much attention, because most of organic
compounds are hydrophobic, whereas the surface of TiO
particle is hydrophilic.
Silanization, absorption of surfactants and hydrophobic substrates could facilitate
the transfer of organic compounds from solution to TiO
particle surface [5, 6].
The replacement of the hydroxyl group by ﬂuorine is also promising to reduce the
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