High-density Pd nanoparticles distribution on PEDOT obtained through electroless metal deposition on pre-reduced polymer layers

Pd electroless deposition is carried out at the expense of oxidation of pre-reduced poly(3,4-ethylene dioxythiophene) (PEDOT)-coated electrodes. Two largely differing potentials for deep and mild pre-reduction of PEDOT are chosen and correspond to initial low (deep pre-reduction) and, correspondingly, high (mild pre-reduction) conductive states of the polymer material. The role of organic doping ions (polysterene sulfonate, PSS or dodecyl sulfate, SDS) used in the course of PEDOT synthesis for the electroless deposition of Pd is also investigated. PEDOT-supported Pd catalysts with high-density homogeneous distribution of Pd nanoparticles (NPs) with sizes ranging between 4 and 12 nm are obtained. The amount of deposited metal depends significantly on the pre-reduction potential of PEDOT whereas the surface density of the metal NPs is largely influenced by the doping ions used to obtain the PEDOT material. Evidence for irreversible structural transformation obtained upon deep pre-reduction of PEDOT:SDS is obtained.