The Influence of La Doping on Structural, Optical …
375
3.7 Photocatalytic Studies
Photocatalysis testing was carried out to establish the effect of La on TiO 2 photoactivity. Safranine T photodegradation has been tested as a model reaction. The adsorption–desorption equilibrium was achieved within 120 min. The values of ST adsorption for TiO 2 , 1La/TiO 2 , 2La/TiO 2 were 5.2, 8.1, 15.3%, respectively. Each photocatalytic experiment was performed for 2 h by sampling every 30 min. The degradation
percentages of ST at the corresponding concentration were calculated using the
formula presented in (1).
Degradation% = ((C 0 − C − t)/C 0 )x100
(1)
In our experiment, La/TiO 2 nanocomposites show higher photocatalytic activity
than pure TiO 2 and P25 (Fig. 10).
As known, the dye molecules are able to absorb UV light with their following
chemical transformations. The blank experiment (irradiation of the dye aqueous
solution without a photocatalyst) showed that less than 10 (after 1 h) and 20% (after
2 h) of SF dye molecules undergo photolysis processes under UV light. The direct
photocatalysis along with indirect photocatalytic processes can take place in the
systems containing a photocatalyst and dye molecules with appropriate excited state
reduction potential. However, direct photocatalysis occurs mainly in the presence of
a semiconductor catalyst, as can be seen, doping of TiO 2 with lanthanum affects the
percent decolorization of the dye.
Fig. 10 Discoloration of ST after 1 (dark bars) and 2 (gray bars) hours
375
3.7 Photocatalytic Studies
Photocatalysis testing was carried out to establish the effect of La on TiO 2 photoactivity. Safranine T photodegradation has been tested as a model reaction. The adsorption–desorption equilibrium was achieved within 120 min. The values of ST adsorption for TiO 2 , 1La/TiO 2 , 2La/TiO 2 were 5.2, 8.1, 15.3%, respectively. Each photocatalytic experiment was performed for 2 h by sampling every 30 min. The degradation
percentages of ST at the corresponding concentration were calculated using the
formula presented in (1).
Degradation% = ((C 0 − C − t)/C 0 )x100
(1)
In our experiment, La/TiO 2 nanocomposites show higher photocatalytic activity
than pure TiO 2 and P25 (Fig. 10).
As known, the dye molecules are able to absorb UV light with their following
chemical transformations. The blank experiment (irradiation of the dye aqueous
solution without a photocatalyst) showed that less than 10 (after 1 h) and 20% (after
2 h) of SF dye molecules undergo photolysis processes under UV light. The direct
photocatalysis along with indirect photocatalytic processes can take place in the
systems containing a photocatalyst and dye molecules with appropriate excited state
reduction potential. However, direct photocatalysis occurs mainly in the presence of
a semiconductor catalyst, as can be seen, doping of TiO 2 with lanthanum affects the
percent decolorization of the dye.
Fig. 10 Discoloration of ST after 1 (dark bars) and 2 (gray bars) hours