Conformal deposition of Pt on titania nanotubes to produce a bio-electrode for neuro-stimulating applications

Abstract

We develop an alkaline electroless bath for deposition of a conformal Pt layer 40 nm thick on titania nanotubes 800 nm long. The charge storage capacity (CSC) and electrochemically active surface area (ECSA) of this Pt-coated titania nanotube array have been studied to evaluate its potential as a bio-electrode for implantable bio-electronic devices. Images from electron microscopes confirm the formation of a uniform Pt film on both the internal and external surfaces of the nanotubes. The X-ray diffraction pattern indicates a preferred (111) orientation. Analysis from X-ray absorption spectroscopy on the plating bath suggests a reduction sequence of Pt4+ → Pt2+ → Pt. The Pt-coated titania nanotube array has large CSC and ECSA values, attributed to the hollow tubular nanostructure with a conformal Pt coating.