The formation of nanostructured TiO2 oxides in the form of nanotubes or nanopores grown on Ti films was investigated. Ti thin films were deposited by radio-frequency (RF) magnetron sputtering on silicon substrates and then anodized. Anodization was performed in glycerol electrolytes containing 0.6 wt.% and 1.2 wt.% ammonium fluoride (NH4F) with an applied potential from 20 to 60 V. The morphology and structure were identified by means of scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The effects of fluoride concentration on the formation of nanotubes or nanopores prepared on Ti thin layer have not been understood, besides most of the works are focused on Ti sheet. We show in the present work that a simple parameter as the NH4F content in the electrolyte can turn the morphology from porous to tubular. It can allow an understanding of the mechanism of formation of pores/tubes and its practical impact.
[1]
G.K.Mor, M.A.Carvalho, O.K.Varghese, M.V. Pishko, C.A Grimes, A room temperature TiO2 nanotube hydrogen sensor able to self-clean photoactively from environmental contamination, J. Mater. Res. 19, 628-634¬ (2004).
[2]
O.K.Varghese, G.K.Mor, C.A.Grimes, M.Paulose, N.Mukherjee, A Titania Nanotube-Array Room-Temperature Sensor for Selective Detection of Hydrogen at Low Concentrations, J. Nanosci. Nanotechnol. 4, 733-737¬(2004).
[3]
P.M. Perillo, D.F. Rodriguez, ¨The gas sensing properties at room temperature of TiO2 nanotubes by anodization¨, Sens. Actuat. B 171-172, pp 639-643, (2012).
[4]
P.M. Perillo, D.F. Rodríguez, A room temperature chloroform sensor using TiO2 nanotubes, Sens. Actuat B, Vol 193, 263-266 (2014).
[5]
E. Şennik, Z.Colak, N.Kılınc, Z. Ziya Oüzturk, Synthesis of highly-ordered TiO2 nanotubes for a hydrogen sensor, Intern. J. of Hydrog Energy 35, 4420-4427 (2010).
[6]
K. Shankar, G.K. Mor, H.E. Prakasam, S. Yoriya, M. Paulose, O.K Varghese, C.A. Grimes, Highly-ordered TiO2 nanotube arrays up to 220 μm in length: use in water photoelectrolysis and dye-sensitized solar cells, Nanotechnol. 18 , 065707 (2007).
[7]
J.M. Macák, H. Tsuchiya, A. Ghicov, P. Schmuki, Dye-sensitized anodic TiO2 nanotubes, Electrochem. Commun. 7, 1133-1137 (2005).
[8]
M. Adachi, Y. Murata, I. Okada, Y. Yoshikawa, Formation of Titania Nanotubes and Applications for Dye-Sensitized Solar Cells, J. Electrochem. Soc. 150 G488-G493 (2003).
[9]
S.K. Mohapatra, M. Misra, V.K. Mahajan and K.S. Raja, Design of a highly efficient photoelectrolytic cell for hydrogen generation by water splitting: application of TiO2-xCx nanotubes as a photoanode and Pt/TiO2 nanotubes as a cathode, J. Phys. Chem. C 111 8677-8685 (2007).
[10]
O.K.Varghese, M.Paulose, T.J.LaTempa, High-Rate Solar Photocatalytic Conversion of CO2 and Water Vapor to Hydrocarbon Fuel, Nano Lett. Vol. 9, N° 2 731-737 (2009).
[11]
Y.G.Wang, Zi D. Wang, Y.Y. Xia, An asymmetric supercapacitor using RuO2/TiO2 nanotube composite and activated carbon electrodes, Electrochim. Acta 50, 5641-5646 (2005).
[12]
Q.Wang; Zh.Wen; J.Li., Carbon Nanotubes/TiO2 Nanotubes Hybrid supercapacitor, J. of Nanosci. and Nanotechnol. Vol 7, N° 9, 3328-3331 (2007).
[13]
Oh Seunghan, Ch. Daraio, Li-Han Chen, T.R. Pisanic, R.R. Fiñones, Sungho Jin, Significantly accelerated osteoblast cell growth on aligned TiO2 nanotubes, J. of Biomed. Mater. Res. Part A 78A 97-103 (2006) .
[14]
K.C.Popat, M. Eltgroth, T.J. LaTempa, C.A. Grimes, T.A Desai, Decreased Staphylococcus epidermis adhesion and increased osteoblast functionality on antibiotic-loaded titania nanotubes, Biomater. 28 4880-4888 (2007).
[15]
S.C. Roy, M. Paulose, C.A. Grimes, The effect of TiO2 nanotubes in the enhancement of blood clotting for the control of hemorrhage, Biomater. 28 4667-4672 (2007).
[16]
G.K. Mor, K. Shankar, M. Paulose, O.K. Varghese, C.A. Grimes, Use of highly-ordered TiO2 nanotube arrays in dye-sensitized solar cells, Nano Lett. 6 (2) 215-218 (2006).
[17]
M. Paulose, K. Shankar, O.K. Varghese, G.K. Mor, C.A. Grimes, Application of highly-ordered TiO2 nanotube-arrays in heterojunction dye-sensitized solar cells, J. Phys D: Appl Phys, 39(12) 2498-2503 (2006) .
[18]
G.K. Mor, O.K. Varghese, M. Paulose, C.A. Grimes, Transparent Highly Ordered TiO2 Nanotube Arrays via Anodization of Titanium Thin Films, Adv. Funct. Mater., 15 (8) 1291-1296 (2005).
[19]
A.J. Leenheer, A. Miedaner, C.J. Curtis, M.F.A.M. Van Hest, D.S. Ginley, Fabrication of nanoporous titania on glass and transparent conducting oxide substrates by anodization of titanium films, J. Mater. Res., 22 (3) 681-687(2007).
[20]
S.Z.Chu, S.Inoue, K. Wada, S. Hishita, K. Kurashima, Self-Organized Nanoporous Anodic Titania Films and Ordered Titania Nanodots/Nanorods on Glass, Adv. Funct. Mater., 15 (8) 1343-1349 (2005).
[21]
Abu Z. Sadek, Haidong Zheng, Kay Latham, Wojtek Wlodarski, and Kourosh Kalantar-zadeh, Anodization of Ti Thin Film Deposited on ITO, Langmuir, 25, 509-514 (2009).
[22]
X.F. Yu, Y.X. Lu, W. Wlodarski, S Kandasamy., K. Kalantar-Zadeh, Fabrication of nanostructured TiO2 by anodization: A comparison between electrolytes and substrates, Sens and Actuat. B, 130, 25-31 (2008).
[23]
J.M. Macák, H. Tsuchiya, S. Berger, S. Bauer, S. Fujimoto, P. Schmuki, On wafer TiO2 nanotube-layer formation by anodization of Ti-films on Si, Chem Phys Letters 428, 421-425 (2006).
[24]
Y.D.Premchand, T.Djenizian, F.Vacandio, P.Knauth, Fabrication of self-organized TiO2 nanotubes from columnar titanium thin films sputtered on semiconductor surfaces Electrochem. Commun. 8, 1840-1844 (2006).
[25]
X.F. Yu, Y.X. Li, W. Ge, Q. Yang, N. Zhu, K.Kalantar-Zadeh, Formation of nanoporous titanium oxide films on silicon substrates using an anodization process, Nanotechnol. 17 808-814 (2006).
[26]
E K. Kalantar-Zadeh, A.Z. Sadek, H. Zheng, J.G. Partridge, D.G. McCulloch, Y.X. Li, X.F. Yu, W. Wlodarski, Effect of crystallographic orientation on the anodic formation of nanoscale pores/tubes in TiO2 films, Applied Surf. Sci. 256, 120-123 (2009).
[27]
E K. Kalantar-Zadeh, A.Z. Sadek, J.G. Partridge, D.G. McCulloch, Y.X. Li, X.F. Yu, P.G. Spizirri, W. Wlodarski, Nanoporous titanium oxide synthesized from anodized Filtered Cathodic Vaccuum Arc Ti thin films, Thin solid films 518, 1180-1184 (2009).
[28]
G.Patermarakis, K.Moussoutzanis, Mathematical Models for the Anodization Conditions and Structural Features of Porous Anodic Al2 O 3 Films on Aluminum, J. Electrochem. Soc. 142 737-743 (1995).
[29]
J.M. Macák, S. Aldabergerova, A. Ghicov, P. Schmuki, Smooth anodic TiO2 nanotubes: annealing and structure, Physica status solidi (a) 203, 67-69 (2006).
[30]
D. Regonini, A Jaroenworaluck., R. Stevens and C.R. Bowen, Effect of heat treatment on the properties and structure of TiO2 nanotubes: phase composition and chemical composition, Surf. Interface Anal. 42, 139-144 (2010).
[31]
S. Ben Amor, L. Guedri, G. Baud, M. Jacquet, M. Ghedira, Influence of the temperature on the properties of sputtered titanium oxide films, Mater.Chem. and Phys. 77 , 903-911 (2002).
[32]
D. Regonini, C.R. Bowen, A Jaroenworaluck, R. Stevens, A review of growth mechanism structure and crystallinity of anodized TiO2 nanotubes, Mat. Sci. and Eng. R 377-406 (2013).
[33]
D.Kowalski, D.Kim, P. Schmuki, TiO2 nanotubes, nanochannels and mesosponge: Self-organized formation and applications, Nano today 8 (3), 235-264 (2013).
[34]
S. Berger, S. Albu, F. Schmidt-Stein, H. Hildebrand, P. Schmuki, J. Hammond, D. Paul, S. Reichlmaier, The origin for tubular growth of TiO2 nanotubes: A fluoride rich layer between tube-walls, Surf. Sci. 10, 1916-1919 (2011).
[35]
H. Habazaki, K. Fushimi, K. Shimizu, P. Skeldon, G.E. Thompson, Fast migration of fluoride ions in growing anodic titanium oxide, Electrochem. Commun. 9 1222-1227 (2007).
[36]
K. Shimizu, K. Kobayashi, E. Thompson, P. Skeldon, G. C. Wood, The Migration of Fluoride Ions in Growing Anodic Oxide Films on Tantalum, J. of Electrochem. Soc, Vol 144, N° 2, 418-423 (1997).
