Formation of 8 nm TiO2 nanotubes on a three dimensional electrode for enhanced photoelectrochemical reaction

nt matter & 2013 0.1016/j.nanoen.2 thor at: Materia rnia at San Diego 3; fax: +1 858 534 [email protected] (S. J Abstract We report here a successful fabrication of a 3-D photoelectrode configuration having hydrothermally formed TiO2 nanotubes on parallel Ti fins. The Ti fin arrays were assembled by simple and facile spot welding of alternately tall and short Ti foil assembly, which provides significantly increased electrode surface area. A tangled forest of nanotubes of TiO2 was produced on each of the Ti surface on all parallel and straight fin arrays. UV absorption spectra of the TiO2 nanotubes indicate that the TiO2 nanotubes are photo-excited due to their photocatalytic activities, and the charge separation is accomplished by the transfer of photoexcited electrons from the TiO2 nanotubes to the Ti metallic substrate, thereby performing photoelectrochemical reaction. By virtue of substantially increased surface area with the 3-D photoelectrode, significantly increased (by ∼300%) photocurrent density was obtained with the photocatalysis of TiO2 nanotubes in combination with enhanced electrical current path between conducting Ti fin substrates and the photocatalytic TiO2 on the fin surface. Such 3-D straight fin array structures fabricated by a simple and versatile method can be useful as a robust electrode for hydrogen generation by water splitting, CO oxidation and various other types of photocatalysts and photovoltaic cells. & 2013 Elsevier Ltd. All rights reserved.