TiO2-Nafion Photoelectrode Hybridized with Carbon Nanotubes for Sensitized Photochemical Activity

Abstract

The present study describes a photoclectrochemical (PEC) system that employs a hybrid electrode that consists of TiO2 nanoparticles, nafion (Nf) resin, dye sensitizers, and carbon nanotubes (CNTs). By dispersing TiO2 nanoparticles in Nf matrix in the hybrid electrode, dye sensitizers (ruthenium bipyridyl complexes or cationic organic dyes) that do not adsorb on the surface of TiO2 could be easily attached to the electrode through a simple ion exchange process. The CNTs incorporated in the Nf matrix interconnect TiO2 nanoparticles embedded in the insulating polymer matrix and serve successfully as an electron collector and conduit that transports electrons from the excited sensitizers to the underlying conducting electrode (FTO) base. The PEC activity of the hybrid electrode was assessed by measuring the hydrogen production and the photocurrent generation under visible light irradiation. Both the hydrogen production and the photocurrent generation were drastically enhanced with CNTs present in the hybrid electrode. The CNT loading monotonously increased the conductivity of the hybrid film, but the PEC activity was optimized at around 2 wt % of CNT/(CNT + TiO2). The photocurrent to hydrogen conversion efficiency in the PEC cell was fairly constant around 0.50 +/- 0.07 regardless of the composition of the hybrid electrode film.