Control over the tube diameter and wall thickness of nanotube array electrode is essential in optimizing the device performance of nano-photovoltaic cells, Fuel Cells and supercapacitors. A wide range of the tube radius and wall width tunability has been obtained in electro-nano fabrication of free standing perpendicularly oriented TiO2 nanotubes by simple compositional variation of potassium and sodium carbonate at constant potential. The charge transfer mechanism at various electrochemical conditions in fabrication process has been probed with real time impedance spectroscopy. The increased addition of potassium carbonate shows a radial tuning tendency toward the lower diameter side; however the addition of sodium carbonate increases the diameter with higher concentration. The impedance analysis and real time current analysis reveals that the change in charge transfer resistance of the electrolyte has significant role for controlling the tube morphology in transverse direction. (C) 2015 The Electrochemical Society. All rights reserved.