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]
(1)The 1st UTS-VNU Research School
Advanced Technologies for IoT Applications
SYNTHESIS OF SrTi1–(X+Y)MOXVYO3 AND ITS PHOTOCATALYTIC ACTIVITIES
OF UNDER VISIBLE LIGHT IRRADIATION
Abstract
Figure 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 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
1.2 Photocatalytic decomposition of
methylene blue (MB)
Figure X-ray diffraction of SrTi1-(x+y)MoxVyO3 samples calcined at 700 oC for 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 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 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 Pseudo first-order kinetic simulation for MB degradation of SrTi1-xVxO3 samples
2 Results 2 Results
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, 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 Experimental setup model for the photocatalytic degradation of MB
Figure Diffuse reflectance spectra of the synthesized SrTi1-xVxO3 powders calcined at 700 oC for h
1.1. Synthesis of SrTiO3 and M-doped SrTiO3
Ti(OC4H9)4 NH4VO3 Sr(NO3)2
Axit citric C6H8O7
Mixed solution
Gelling
Esterification reaction Treatment
Sample Etylen
Glycol T=80 oC
Stirring h 120ml H2O2 30% +
60ml NH3 25%
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T.-Que Phuong Phan Sy-Nguyen Pham
Minh-Vien Le
Department of Inorganic Chemical
Engineering, Faculty of Chemical
Engineering, Bach Khoa University 268 Ly Thuong Kiet Street, Ward 14, District 10, Ho Chi Minh City
500nm
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6.tif
(b)
(c) (d)
4.tif
(a)
SrTi1–(x-y)MoxVyO3 k (min–1) R2 Equation
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
SrTi1-x-yMoxVyO3 x = 0
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
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2.1 Characterization of photocatalysts
Figure EDS images (a) STO dope Mo 5%, (b) STO dope 5% V, (c) STO co-dope Mo 3%- V 3%
Table The methylene blue degradiation and mineralization of SrTi1-x-yMoxVyO3
Table First-order rate constant and equation for SrTi