Research Synthesis of La3+ Doped TiO2 Nanoparticles by Hydrothermal Method, Study on Photocatalytic Activity of Decomposition of Methylene Blue under Ultraviolet Irradiation

In this study, with the aim of improving the photocatalytic efficiency of TiO2, we studied the synthesis of La3+ doped TiO2 (with doped rates 1%, 2.5%, 5% mol/mol compared to Ti4+) by hydrothermal method. The hydrothermal condition was set at 180 °C for 12 hours. Material characteristics were investigated by XRD, SEM and solid UV-Vis methods. The results show that, all prepared materials have a crystal particle size of about nano-meters, small and smooth (4.5¸6.5 nm). La3+ doped TiO2 samples had a shift towards longer wavelengths (l» 400¸500 nm) compared to non-doped TiO2 sample (l£ 380 nm). The band gap energy (Eg) of La3+ doped TiO2 samples was reduced to 3.04¸3.10 eV . The yield of MB degradation of La3+ doped TiO2 at 5% mol/mol reached the highest ~93% after 60 minutes under ultraviolet irradiation. Keywords Anatase TiO2, photocatalysis, La3+ doped TiO2, hydrothermal method, ultraviolet irradiation. References [1] D. Nassoko, Y. F. Li, H. Wang, J. L. Li, Y. Z. Li, Y. Yu, Nitrogen-doped TiO2 nanoparticles by using EDTA as nitrogen source and soft template: Simple preparation, mesoporous structure, and photocatalytic activity under visible light, Journal of Alloys and Compounds. 540 (2012) 228-235. https://doi.org/10.1016/j.jallcom.2012.06.085.[2] M. Khatamian, S. Hashemian, A. Yavari, M. Saket, Preparation of metal ion (Fe3+ and Ni2+) doped TiO2 nanoparticles supported on ZSM-5 zeolite and investigation of its photocatalytic activity, Materials Science and Engineering B. 177 (2012) 1623-1627. http://dx.doi.org/10.1016/ j.mseb.2012.08.015.[3] X. Zhang, Q. Liu, Visible-light-induced degradation of formaldehyde over titania photocatalyst co-doped with nitrogen and nickel, Applied surface Science. 254(15) (2008) 4780-4785. https://doi.org/10.1016/j.apsusc.2008.01.094.[4] Y. Wang, H. Cheng, L. Zhang, Y. Hao, J. Ma, B. Xu, W. Li, The preparation, characterization, photoelectrochemical and photocatalytic properties of lanthanide metal-ion-doped TiO2 nanoparticles, Journal of Molecular Catalysis A: Chemical. 151 (2000) 205-216. https://doi.org/10. 1016/s 1381-1169(99)00245-9[5] M. Meksi, G. Berhault, C. Guillard, H. Kochkar, Design of TiO2 nanorods and nanotubes doped with lanthanum and comparative kinetic study in the photodegradation of formic acid, Catalysis Communications. 61 (2015) 107-111. https://doi. org/ 10.1016/j.catcom.2014.12.020.[6] Q. Wang, S. Xu, F. Shen, Preparation and characterization of TiO2 photocatalysts co-doped with iron (III) and lanthanum for the degradation of organic pollutants, Applied Surface Science. 257 (2011) 7671-7677. https://doi.org/10.1016/j. apsusc.2011.03.157.[7] L. Elsellami, H. Lachheb, A. Houas, Synthesis, characterization and photocatalytic activity of Li, Cd-, and La-doped TiO2, Materials Science in Semiconductor Processing. 36 (2015) 103-114. https://doi.org/10.1016/j.mssp.2015.03.032.[8] J. Nie, Y. Mo, B. Zheng, H. Yuan, D. Xiao, Electrochemical fabrication of lanthanum-doped TiO2 nanotube array electrode and investigation of its photoelectrochemical capability, Electrochimica Acta. 90 (2013) 589-596. http://dx.doi.org/10. 1016/j.electacta. 2012.12.049.[9] Y. Chen, Q. Wu, C. Zhou, Q. Jin, Enhanced photocatalytic activity of La and N co-doped TiO2/diatomite composite, Powder Technology. 322 (2017) 296-300. http://dx.doi.org/10.1016/ j.powtec.2017.09.026. [10] I. Ganesh, P. P. Kumar, I. Annapoorna, J. M. Sumliner, M. Ramakrishna, N. Y. Hebalkar, G. Padmanabham, G. Sundararajan, Preparation and characterization of Cu-doped TiO2 materials for electrochemical, photoelectrochemical, and photocatalytic applications, Applied Surface Science, 293 (2014) 229-247. http://dx.doi.org/10. 1016/j.apsusc.2013.12.140.