A photoelectrochemical biofuel cell based on a TiO₂ nanotube array fluorine-doped tin oxide photoanode

Abstract

Photoelectrochemical biofuel cells can convert light and chemical energy into electrical energy using a dye-sensitized titania (TiO 2 ) fluorine-doped tin oxide photoanode and a platinum-coated fluorine-doped tin oxide cathode. TiO 2 of the photoanode serves both as a support for dyes and as an electron-transporting medium, the structure of which can limit electron trapping and charge transporting and then affect the performance of the photoelectrochemical biofuel cells. TiO 2 nanotube array films have been shown to enhance the efficiencies of both charge collection and electron injection, and hence a vertically aligned TiO 2 nanotube array is investigated as a conductor for the tetrakis(4-carboxyphenyl)porphyrin dye to construct a new two-compartment photoelectrochemical biofuel cell. The photoelectrochemical biofuel cell containing the TiO 2 nanotube array photoanode yields a short-circuit (I sc ) current of 110 μA and an open-circuit (V oc ) potential of 1010 mV. In contrast, the photovoltaic parameters, I sc and V oc of the photoelectrochemical biofuel cell with the mesoporous TiO 2 nanocrystal fluorine-doped tin oxide photoanode, are 96.96 μA and 740 mV, respectively. Photovoltaic measurements show that the maximum incident photon-to-collected electron conversion efficiency was 58% at 430 nm through the spectral range (400–800 nm) for the photoelectrochemical biofuel cell with the TiO 2 nanotube array fluorine-doped tin oxide photoanode. These results revealed that the TiO 2 nanotube array had great potential for the photoelectrochemical biofuel cells.