Use of Nation as a Solid Polymer Electrolyte for the Electroreduction of Tungsten (VI) Fluoride

A new method is described in which WF₆ is electroreduced in a solid-state cell configuration with a Nation membrane serving as a solid polymer electrolyte. Cyclic voltammetry indicates a behavior similar to that of metallic tungsten for coatings obtained at dry conditions and similar to that of tungsten oxide species when water vapor is not totally expelled. Surface analysis using Auger electron spectroscopy and x-ray photoelectron spectroscopy shows that solid-state electroreduction of WF₆ in dry conditions yields coatings free of fluorine, which contain much less oxygen than electrodeposits obtained from aqueous solutions. However, due to possible oxidation and reduction reactions occurring before and during the surface-analysis process, it is not possible at this stage to determine the exact content of metallic and oxide species in the deposits obtained by the present method.