Vo Quang Mai, Vo Chi Hao, Nguyen Huu Tho, Nguyen Xuan Sang

Main Article Content

Abstract

In this study, the composite of titanium dioxide nanotube (TNT) and graphene nanoplatelet was hydrothermally synthesized in a sodium hydroxide solution. Morphological and crystalline properties of the synthesized samples were analyzed by transmission electron microscopy (TEM), X-ray differactometry (XRD), and Raman spectroscopy. Optical properties were investigated by UV-Vis diffuse reflextance spectra (DRS) where optical bandgap was determined. Photocatalytic activity of the synthesized samples was evaluated through the degradation of methylene blue in the solution under direct sunlight irradiation. The result showed the enhancement of photocatalytic activity in the composite sample in compare to the bare TNT. After 120 min of irradiation, the photocatalytic efficiency of the composite and TNT was ~95% and 63%, respectively. Mechanism of enhanced activity was supported by DRS measurements in which the composite showed the higher visible light absoption and lower bandgap value. Optical bandgap of the sGr/TNT composite was about 3.25 eV which was notably reduced in compare to that of the bare TNT of ~3.68 eV.
Keywords: titanium nanotube, graphene, heterostructure, photocatalysis, DRS.

References

[1] B. Tang, H. Chen, H. Peng, Z. Wang, W. Huang, Graphene modified TiO2 composite photocatalysts: mechanism, progress and perspective, Nanomaterials 8 (2018) 105. https:// doi.org/10.3390/nano8020105.
[2] V. Etacheri, C. Di Valentin, J. Schneider, D. Bahnemann, S.C. Pillai, Visible-light activation of TiO2 photocatalysts: Advances in theory and experiments, Journal of Photochemistry and Photobiology C: Photochemistry Reviews 25 (2015) 1-29. https://doi.org/10.1016/j.jphotochemrev.2015. 08.003.
[3] H.H. Ou, S.L. Lo, Review of titania nanotubes synthesized via the hydrothermal treatment: Fabrication, modification, and application, Separation and Purification Technology 58 (2007)179-191. https://doi.org/10.1016/j.seppur. 2007.07.017.
[4] N. Liu, X. Chen, J. Zhang, J.W. Schwank, A review on TiO2-based nanotubes synthesized via hydrothermal method: Formation mechanism, structure modification, and photocatalytic applications, Catalysis Today 225 (2014) 34-51. https://doi.org/10.1016/j.cattod.2013.10.090.
[5] Q. Chen, G. Du, S. Zhang, L.-M. Peng, The structure of trititanate nanotubes, Acta Crystallographica Section B: Structural Science 58(2002)587-593. https://doi.org/10.1107/S0108 768102009084.
[6] J. Yang, Z. Jin, X. Wang, W. Li, J. Zhang, S. Zhang, X. Guo, Z. Zhang, Study on composition, structure and formation process of nanotube Na2Ti2O4(OH)2, Dalton Transactions (2003)3898-3901. https://doi.org/10.1039/B305585J.
[7] S.D. Perera, R.G. Mariano, K. Vu, N. Nour, O. Seitz, Y. Chabal, K.J. Balkus Jr, Hydrothermal synthesis of graphene-TiO2 nanotube composites with enhanced photocatalytic activity, ACS Catalysis 2 (2012) 949-956. https://doi.org/10. 1021/cs200621c.
[8] X. Zhang, B. Zhang, D. Huang, H. Yuan, M. Wang, Y. Shen, TiO2 nanotubes modified with electrochemically reduced graphene oxide for photoelectrochemical water splitting, Carbon 80 (2014)591-598. https://doi.org/10.1016/j.carbon. 2014.09.002.
[9] H. Tao, X. Liang, Q. Zhang, C.-T. Chang, Enhanced photoactivity of graphene/titanium dioxide nanotubes for removal of Acetaminophen, Applied Surface Science 324 (2015)258-264. https://doi.org/10.1016/j.apsusc. 2014.10.129.
[10] Y. Zhang, Z.-R. Tang, X. Fu, Y.-J. Xu, TiO2− graphene nanocomposites for gas-phase photocatalytic degradation of volatile aromatic pollutant: is TiO2− graphene truly different from other TiO2−carbon composite materials?, ACS Nano 4 (2010) 7303-7314. https://doi.org/10. 1021/nn1024219.
[11] T. Kasuga, M. Hiramatsu, A. Hoson, T. Sekino, K. Niihara, Titania nanotubes prepared by chemical processing, Advanced Materials 11 (1999)1307-1311. https://doi.org/10.1002/(SICI) 1521-4095(199910)11:15<1307::AID-ADMA1307>3.0.CO;2-H.
[12] X. Pan, Y. Zhao, S. Liu, C.L. Korzeniewski, S. Wang, Z. Fan, Comparing graphene-TiO2 nanowire and graphene-TiO2 nanoparticle composite photocatalysts, ACS applied materials & interfaces 4 (2012) 3944-3950. https://doi.org/ 10.1021/am300772t.
[13] F. Hardcastle, Raman spectroscopy of titania (TiO2) nanotubular water-splitting catalysts, Journal of the Arkansas academy of science 65 (2011) 43-48.
[14] F. Jiang, S. Zheng, L. An, H. Chen, Effect of calcination temperature on the adsorption and photocatalytic activity of hydrothermally synthesized TiO2 nanotubes, Applied Surface Science 258 (2012) 7188-7194. https://doi.org/10. 1016/j.apsusc.2012.04.032.
[15] U. Balachandran, N. Eror, Raman spectra of titanium dioxide, Journal of Solid State Chemistry 42 (1982) 276-282.
[16] L. Qian, Z.-L. Du, S.-Y. Yang, Z.-S. Jin, Raman study of titania nanotube by soft chemical process, Journal of Molecular Structure 749 (2005)103-107. https://doi.org/10.1016/j.molstruc.2005.04. 002.
[17] S.X. Nguyen, T.T. Tung, P.T.L. Huong, N.H. Tho, D. Losic, Heterojunction of graphene and titanium dioxide nanotube composites for enhancing photocatalytic activity, Journal of Physics D: Applied Physics 51 (2018) 265304. https://doi.org/10.1088/1361-6463/aac7ce.
[18] L.C. Sim, K.H. Leong, S. Ibrahim, P. Saravanan, Graphene oxide and Ag engulfed TiO2 nanotube arrays for enhanced electron mobility and visible-light-driven photocatalytic performance, Journal of Materials Chemistry A 2 (2014) 5315-5322. https://doi.org/10.1039/C3TA14857B.
[19] P. Song, X. Zhang, M. Sun, X. Cui, Y. Lin, Graphene oxide modified TiO2 nanotube arrays: enhanced visible light photoelectrochemical properties, Nanoscale 4 (2012) 1800-1804. https://doi.org/10.1039/C2NR11938B.
[20] Q. Huang, S. Tian, D. Zeng, X. Wang, W. Song, Y. Li, W. Xiao, C. Xie, Enhanced photocatalytic activity of chemically bonded TiO2/graphene composites based on the effective interfacial charge transfer through the C–Ti bond, Acs Catalysis 3 (2013) 1477-1485. https://doi.org/10. 1021/cs400080w.
[21] Q. Zhang, Y. Li, E.A. Ackerman, M. Gajdardziska-Josifovska, H. Li, Visible light responsive iodine-doped TiO2 for photocatalytic reduction of CO2 to fuels, Applied Catalysis A: General 400 (2011) 195-202. https://doi.org/10. 1016/j.apcata.2011.04.032.
[22] D.V. Bavykin, S.N. Gordeev, A.V. Moskalenko, A.A. Lapkin, F.C. Walsh, Apparent two-dimensional behavior of TiO2 nanotubes revealed by light absorption and luminescence, The Journal of Physical Chemistry B 109 (2005) 8565-8569. https://doi.org/10.1021/jp050762m.
[23] W. Fang, M. Xing, J. Zhang, Modifications on reduced titanium dioxide photocatalysts: A review, Journal of Photochemistry and Photobiology C: Photochemistry Reviews 32 (2017)21-39. https://doi.org/10.1016/j.jphoto chemrev.2017.05.003.