96
T. Su et al. / Catalysis Communications 18 (2012) 93–97
Table 3
Degradation rate as a function of calcination temperatures and pseudo-first order rate
constants derived from fitting experimental data to computer model.
Calcination temperature
°C)
Rate constant
Correlation coefficient,
R
−
3
−1
2
(
(10
min
)
5
6
7
8
9
00
00
00
00
00
2.72
3.99
5.10
16.81
7.81
0.9621
0.9874
0.9930
0.9934
0.9736
reaction rate constant of PbYO photocatalyst calcined at 800 °C is
8
3
.6 times than that of BiYO photocatalyst calcined at 750 °C.
4
. Conclusions
The preparation of PbYO complex photocatalysts calcined at dif-
Fig. 5. Effects of calcination temperature on PbYO composite photocatalysts catalytic
degradation of methyl orange under visible-light irradiation.
ferent temperatures were characterized and evaluated for their
photocatalytic activity in degrading methyl orange under visible-
light irradiation. It was found that these photocatalysts have good vis-
ible-light absorption. The calcination temperature was found to have
a significant effect on photocatalytic activity of the materials. The
complex photocatalyst calcined at 800 °C appeared to have a hetero-
3
.2. Photocatalytic degradation of MO under visible-light irradiation
Fig. 5 shows the results of using the samples of PbYO calcined at
different temperatures as photocatalysts with visible light. The data
show that the calcination temperature has a significant effect on the
degradation results.
2.18
junction structure of PbO and Pb1.81Y O6.78 with a band gap of
2
.44 eV and exhibited the highest photoactivity.
Specifically, after irradiation by visible light for 150 min, the deg-
radation of methyl orange was 34.8%, 44.1%, 51.3%, 93.0%, and
Acknowledgements
7
5
0.1%, respectively, using the PbYO composite oxides calcined at
00 °C, 600 °C, 700 °C, 800 °C, and 900 °C as photocatalysts. The deg-
This work was supported by the National Natural Science Founda-
tion of China (21006013), the Scientific Research Foundation of
Guangxi University (XBZ090780) and the National Students Innova-
tion Experiment Program in Guangxi University (201017). We also
thank Dr. Donald G. Barnes for his helpful discussions about language
of the paper.
radation data of MO show that the optimal calcination temperature of
the PbYO composite photocatalyst is 800 °C. As noted above in the
discussion of the XRD results, when the calcination temperatures
lower than 700 °C, only a single phase of Pb1.81
in the PbYO catalyst. However, when calcined at 800 °C and 900 °C
not only Pb1.81 6.78 but also PbO was found in the PbYO compos-
ite photocatalysts, and a heterostructure may form between the
6.78 and PbO phases. In general, when a kind of hetero
2.18
Y O6.78 was found
Y O
2.18
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2.18
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