3.2. Photocatalytic activity
3.2.1. Photodecolorization of RB5
RB5, a textile azo dye of widespread use, was chosen as target
compound to test the photocatalytic activity of the prepared
catalysts. Fig. 3A presents the evolution of the RB5 concentration
in aqueous medium during the photodecolorization experiments
under UV irradiation in the absence and presence of the TiO2-based
catalysts. The data shows that RB5 is partially photolyzed under UV
irradiation in the absence of catalyst (blank experiment), reaching
a color removal of about 58% after 60 min. The combination of UV
irradiation with Fe3O4@SiO2@TiO2 leads to a RB5 decolorization
of 91% after the same reaction time. This result confirms that the
TiO2 shell in the MNPs is photocatalytically active and promotes the
RB5 oxidation. For comparison, the photocatalytic performances of
TiO2 and P25 were also assessed using the same catalyst concentration
(0.1 g/L). The TiO2 nanocatalyst originates a RB5 decolorization