Titanium Carbide and Titanium Nitride-Based Nanocomposites as Efficient Catalysts for the Co²⁺/Co³⁺ Redox Couple in Dye-Sensitized Solar Cells

Two different kinds of nanocomposites were developed by electrochemical deposition of poly­(3,4-ethylenedioxythiophene) (PEDOT) into porous hard template films of TiC or TiN nanoparticles, in order to evaluate their use as alternative catalysts in dye-sensitized solar cells (DSSC) utilizing a Co²⁺/Co³⁺ polypyridyl redox mediator. Cyclic voltammograms indicate that both types of nanocomposite show comparable catalytic activity to platinum-coated electrodes. However, electrochemical impedance spectroscopy (EIS) reveals that electron transfer resistances are significantly reduced with the porous nanocomposite electrodes (