Photocatalytic material SrTi 1-(x+y) Mo x V y O 3 have been successfully synthesized by sol-gel method at 700 °C, 6 hours and photocatalytic activity evaluation has been conducted using [r]
Trang 1The 1 st UTS-VNU Research School
Advanced Technologies for IoT Applications
OF UNDER VISIBLE LIGHT IRRADIATION
Abstract
Figure 1 Flowchart of SrTi1-xVxO3 synthesis process using
sol-gel method
Single–phase perovskite strontium titanate SrTiO3 was
synthesized from strontium nitrate and tetra–n–butyl
orthotitanate using sol–gel method with various calcined
temperature from 600–900 °C Prepared catalysts were
characterized by X–ray diffraction (XRD), scanning
electron microscope (SEM), ultraviolet–visible diffuse
reflection spectroscopy (UV–DRS). The result showed that
SrTiO3, which was synthesized at 700 °C in 6 hours,
possessed the efficiency of 59.9 % regarding photocatalytic
activity for the 10 ppm methylene blue degradation under
visible (λ = 390 ÷ 750 nm) Furthermore, the results
indicated that the doping of M (M = Mo, V) into the
structure SrTiO3 (SrTi1-(x+y)MoxVyO3) increased the
degradation efficiency in comparison with that of the
undoped SrTiO3 As a result, the presence of Mo, V
contributed to the decrease of band-gap energy and
enhanced simultaneously the photocatalytic activity of
SrTiO3
methylene blue (MB)
Figure 3 X-ray diffraction of SrTi1-(x+y)MoxVyO3 samples calcined at 700 oC for 6 h (a) x = y = 0; (b) x = 0.05, y = 0;
(c) x = 0, y = 0.05; (d) x = y = 0.03 and (e) x = y = 0.05
Figure 4 SEM images of the synthesized photocatalysts of SrTi1-(x+y)MoxVyO3 ((a) STO pure, (b) STO dope Mo 5%, (c) STO dope 5% V, (d) STO
co-dope Mo 3% - V 3%)
Figure 7 Photocatalytic activity of SrTi1-xVxO3 samples (a) before and (b) after acid treatment in the degradation of MB
under visible light for 300 minutes
Figure 8 Pseudo first-order kinetic simulation for MB
degradation of SrTi1-xVxO3 samples
1 Experiment
2.2 Photocatalytic activity of photocatalysts
Photocatalytic material SrTi1-(x+y)MoxVyO3 have been successfully synthesized by sol-gel method at 700 °C, 6 hours and photocatalytic activity evaluation has been conducted using visible light with wavelength of 390–750
nm When STO doped 5% Mo, band gap energy decreased from 3.2 eV to 2.65 eV, photocatalytic decomposition of SrTi0.95Mo0.05O3 sample was the highest (83.4%) and 63.3% mineralization As for 5% V doped (SrTi0.95V0.05O3) and 3% V-3% Mo co-doped (SrTi0.94Mo0.03V0.03O3), MB degradation efficiency as well as mineralization were lower than 5% Mo doped sample
3 Conclusion
Acknowledgement
The authors would like to acknowledge the support of Department of Inorganic Chemical Engineering, Ho Chi Minh City University of technology for conducting UV measurement
Figure 2 Experimental setup model for the photocatalytic
degradation of MB
Figure 6 Diffuse reflectance spectra of the synthesized
SrTi1-xVxO3 powders calcined at 700 oC for 6 h
1.1 Synthesis of SrTiO3 and M-doped SrTiO3
Ti(OC 4 H 9 ) 4 NH 4 VO 3 Sr(NO 3 ) 2
Axit citric C 6 H 8 O 7
Mixed solution
Gelling
Esterification reaction
Treatment Sample
Etylen Glycol T=80 o C
Stirring 4 h
120ml H 2 O 2 30% + 60ml NH 3 25%
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T.-Que Phuong Phan
Sy-Nguyen Pham
Minh-Vien Le
Engineering, Bach Khoa University 268 Ly
Thuong Kiet Street, Ward 14, District 10, Ho
Chi Minh City
500nm
(b)
(b)
(c)
(a)
6.tif
(b)
4.tif
(a)
x = y = 0
x = 0.05, y = 0
x = 0, y = 0.05
x = y = 0.03
2.64 x 10-3 4.08 x 10-3 3.57 x 10 -3
2.87 x 10 -3
0.982 0.942 0.973 0.979
y = 0.0156x + 0.1854
y = 0.0442x + 0.6117
y = 0.0257x + 0.2899
y = 0.0186x + 0.1960
y = 0
x = 0.05
y = 0
x =0
y = 0.05
x = 0.03
y = 0.03 Efficiency (%) 59.9 83.4 73.8 70.2
Mineralization (%) 45.1 63.3 59.9 52.4
500nm
500nm
(b)
(b)
(c)
(a) (a)
(d)
2.1 Characterization of photocatalysts
Figure 5 EDS images (a) STO dope Mo 5%, (b) STO dope
5% V, (c) STO co-dope Mo 3%- V 3%
Table 1 The methylene blue degradiation and mineralization of
SrTi1-x-yMoxVyO3
Table 2 First-order rate constant and equation for SrTi
1-(x+y)MoxVyO3