Thin porous palladium layers modified by cathodically doped graphene and organic donors

Abstract

Thin porous layers of palladium deposited onto gold or Pd bulk metal treated by cathodic reduction in the presence of CsI under super-dry conditions were tested to establish their reactivity towards electrolytes. Specifically, an iono-metallic layer [Pd4−, TMA+ {TMABF4}] was found to be generated in tetra-alkylammonium salts, especially TMA+, BF4−. This material is then taken as a starting substrate for in situ exchange between BF4− and many electrogenerated organic acceptor anions. Importantly, the list includes doped graphene and electro-active conducting organic polymers in their basic form. Thus, for example, an intriguing Pd–graphene layer can be created as a relatively thick interface, and may be either doped or un-doped, depending on the applied potential. The method was also shown to work with many organic acceptors (coronene, anthraquinone, etc.) immobilized in their reduced state. The proposed method suggests a new strategy for building stable composite materials of considerable interest for use as electrodes and/or in 3D redox applications.