Experimental observation of two‐layer TiO₂ nanotube arrays prepared by stepping‐voltage anodization

Abstract

Two‐layer TiO2 nanotube arrays were produced by stepping down the anodic voltage during which three nanotube interface structures between the top layer and the second layer were observed by SEM. We detected a polygonal ring structure on the top surface of the second layer and offer direct evidence of the growth of this second tube layer both at the cell boundary and right beneath the bottom of the first tube layer. For these processes, a possible growth mechanism is presented. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

RETRACTED: The effect of titanium alloy composition in synthesis of Titania nanotubes

“…Nanotubes are of great interest for a wide array of technological and biological applications, especially due to their high surface-to-volume ratios and size dependent properties. Though some research has been going on in this direction, a considerable focus with application oriented research is essentially needed [1][2][3][4][5][6][7][8]. According to the authors, Titania nanotubes production by economically viable and environment friendly techniques is essentially required.…”

Electrochemical engineering of hollow nanoarchitectures: pulse/step anodization (Si, Al, Ti) and their applications

“…After flat-wall TNTs diverge into multiple branches, further furcation of branched nanotubes produces hierarchically branched nanotubes with complex multilayer structures. 158,[165][166][167][168][169][170][171][172] The pulse voltage is switched between 10 V and 30 V every 10 min in the first three periods and 20 min is adopted during last period of 30 V. It is seen from cross-section image in Fig. 6d that the thickness of vertically patterned TNT arrays increases with anodization time.…”

“…166 The growth of second tube layer is either started from bottom of the first tube layer or the gaps between the nanotubes. 83,171,173 The diameters of branched nanotubes and the number of branches are difficult to manipulate. 64,168,169 Fig.…”

A critical review on the variations in anodization parameters toward microstructural formation of TiO2 nanotubes

“…Many variations in anodization techniques have been tried to improve the functional properties of TiO 2 NTs prepared and stepping-voltage is one among them. [86,87] In this technique, two individual voltage steps were admonished in one anodization technique. Pre-anodization was performed with freshly prepared electrolyte containing ethylene glycol, 6 vol.% water and 0.5 wt.% NH 4 F at 50 V for a period of 3 h. This layer was peeled using sonication in 1 M HCl solution and the base was utilized for the steppinganodization process.…”

“…[77] with permission from Springer, (h) reproduced from Ref. [86] with permission from Wiley, (i) reproduced from Ref. [20] with permission from Springer, (j) reproduced from Ref.…”