Electrochemical behaviour of the crystallised system hydrogen-platinum-uranyl phosphate acid (HUP)

The electrochemical behaviour of the electrode H2-Pt-HUO2PO4.4H2O (HUP) was studied at room temperature, at which HUP is a fast proton conductor. The cathodic reaction was found to be rapid and stable. The anodic reaction is also rapid, provided that it follows a cathodic treatment. In the opposite case a limiting anodic current is observed. Storage for a long time in the presence of water vapour slightly increases this limit and this is attributed to a desiccation of the anodic interface producing a large superficial ohmic drop. It was concluded that in the H2-Pt-HUP-Pt-H2 cell water is produced at the cathodic interface and is consumed at the anodic interface, the kinetics of this second reaction being slow. (Auth.)