st The UTS-VNU Research School Advanced Technologies for IoT Applications SYNTHESIS OF SrTi1–(X+Y)MOXVYO3 AND ITS PHOTOCATALYTIC ACTIVITIES OF UNDER VISIBLE LIGHT IRRADIATION Results Results ????? 2.1 Characterization of photocatalysts 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 Abstract 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 Experiment 1.1 Synthesis of SrTiO3 and M-doped SrTiO3 NH4VO3 Ti(OC4H9)4 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 (b) (a) (a) 4.tif (c) (c) x = 0.03 y=0 y=0 y = 0.05 y = 0.03 59.9 83.4 73.8 70.2 Mineralization (%) 45.1 63.3 59.9 52.4 6.tif 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 codope Mo 3% - V 3%) Sr(NO3)2 (a) (b) Figure Pseudo first-order kinetic simulation for MB degradation of SrTi1-xVxO3 samples Table First-order rate constant and equation for SrTi1(x+y)MoxVyO3 500nm (b) Gelling x = 0.05 x =0 (d) (b) Mixed solution Esterification reaction x=0 Efficiency (%) 500nm Axit citric C6H8O7 Etylen Glycol Table The methylene blue degradiation and mineralization of SrTi1-x-yMoxVyO3 SrTi1-x-yMoxVyO3 (a) 120ml H2O2 30% + 60ml NH3 25% (b) 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 (c) (d) T=80 oC Stirring h Treatment 500nm Sample Figure Flowchart of SrTi1-xVxO3 synthesis process using sol-gel method 1.2 Photocatalytic decomposition methylene blue (MB) of Figure EDS images (a) STO dope Mo 5%, (b) STO dope 5% V, (c) STO co-dope Mo 3%- V 3% 2.2 Photocatalytic activity of photocatalysts SrTi1–(x-y)MoxVyO3 k (min–1) R2 Equation x=y=0 2.64 x 10-3 0.982 y = 0.0156x + 0.1854 x = 0.05, y = 4.08 x 10-3 0.942 y = 0.0442x + 0.6117 x = 0, y = 0.05 3.57 x 10-3 0.973 y = 0.0257x + 0.2899 x = y = 0.03 2.87 x 10-3 0.979 y = 0.0186x + 0.1960 Conclusion 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 Acknowledgement 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 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