Morphological effect of composite TiO2 nanorod-TiO2 nanoparticle/PEDOT:PSS electrodes on triiodide reduction

Abstract

Abstract. Composite electrodes consisting of TiO 2 nanoparticles (NPs)-TiO 2 nanorods (NRs) and poly (3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) were prepared on a conductive glass substrate. The presence of TiO 2 in the composite structure was proved by X-ray diffraction (XRD) Raman and FTIR-ATR measurements. The surface morphologies of TiO 2 NP-PEDOT:PSS, TiO 2 NR-PEDOT:PSS and TiO 2 NP-TiO 2 NR-PEDOT:PSS electrodes were characterized by scanning electron microscopy (SEM). According to the cyclic voltammetry measurement (CV), the electrocatalytic activity of composite electrodes on the reduction of triiodide improved after TiO 2 addition compared with pristine PEDOT:PSS and platinum (Pt) electrodes. Electrochemical impedance spectroscopy (EIS) showed that the charge transfer resistance (R ct ) strongly depends on the morphologies (ratio between TiO 2 NP and TiO 2 NR) of the composite electrodes. It was found that R ct decreased by increasing the amount of TiO 2 nanorod in the whole mixture of TiO 2 nanoparticles and PEDOT:PSS.