Laser synthesis of hierarchically organized nanostructured TiO2 films on microfibrous carbon paper substrate: Characterization and electrocatalyst supporting properties.

Titanium dioxide is cheap, non-toxic, exhibits a high mechanical resistance, very stable in acidic and oxidative environments is being studied as alternative to carbon as catalyst support in low-temperature fuel cells. Herein, via pulsed laser deposition, various morphologies of TiO 2 thin films are synthesized at room temperature onto conductive microfibrous carbon paper substrate, which is the type of substrate, employed in energy storage and conversion devices. TiO 2 films deposited under vacuum and in the presence of mild pressure of oxygen are very smooth and dense. Instead, TiO 2 films deposited in the presence of helium atmosphere are of porous structures and vertically aligned. An increase in the helium pressure leads to the formation of forest-like vertically aligned nanostructures. Micro-Raman spectroscopy reveals that the films are amorphous and of rutile phase. X-ray photoelectron spectroscopy shows that Ti is in fully oxidized state of Ti 4+ . The electrocatalytic supporting properties to Pt are investigated in H 2 SO 4 and O 2 -saturated H 2 SO 4 solution. It is found that regardless of the film morphology, all the synthesized TiO 2 films dramatically increase the electroactive surface area of Pt and enhance its electroactivity towards oxygen reduction reaction as compared with bare Pt electrode. [ABSTRACT FROM AUTHOR]