Photoelectrochemical Studies on High Specific Capacitance-Photoactive Interfaces Based on Poly 3,4- Ethylenedioxythiophene/Metal Oxides Assemblies

摘要

Inorganic/organic interfaces (IOI) consist of TiO2/PEDOT (poly 3,4-ethylenedioxythiophene) and [PMo12O40]3- or MoO3/PEDOT were subject to photoelectrochemical studies in both aqueous nanosuspensions and in thin solid films. The effects PEDOT modifier caused on the photoelectrochemical behavior of the IOI were investigated using [Fe(CN)6]4- as the photoactive hydrated electron donor agent. Results show that native PEDOT or PEDOT doped with MoO3 thin films increased charge storage capability evident by the high capacitive current. In the case of nano suspensions composed of TiO2/PEDOT the adsorption process of [Fe(CN)6]3- (photolysis product) control of the photoactivity outcome of the IOI assemblies. TiO2/PEDOT shows a lower heterogeneous photochemical response than native TiO2 in short term photolysis times. At longer photolysis times the IOI shows photoactivity greater than that of native TiO2. The interface activities were explained by analyzing the IOI junction characteristics, such as electron affinity, work function and hole/electrons barrier heights. The aqueous nano-systems retained moderate stability as indicated by the reproducibility of their photocatalytic activities. Both [Fe(CN)6]4-and PEDT contributed to the stability of native TiO2 surfaces.