Portal de Periódicos da CAPES

Radiotracer and voltammetric study of water at the platinum/propylene carbonate interface

1990; Elsevier BV; Volume: 278; Issue: 1-2 Linguagem: Inglês

10.1016/0022-0728(90)85146-v

2590-2954

Piotr Zelenay, M. Winnicka‐Maurin, Jerzy Sobkowski,

Electrochemical Analysis and Applications

The adsorption and electrode reactions of tritium-labelled water were investigated at the platinum/propylene carbonate (PC) interface in 0.1 M LiClO4 and 0.05 M TBAP (tetrabutylammonium perchlorate) solutions. The radiotracer technique was used to determine the surface concentration of water and other tritium-containing species. Cyclic voltammetry was applied to detect the surface reactions of water in the organic solvent and to study the propylene carbonate adsorption behaviour in aqueous solutions. It was found that water displaces PC molecules and adsorbs on the electrode surface. The maximum measured surface concentration of adsorbed water is about 1.4 × 1014 molecules cm−2 (in 0.1 M solution of water in LiClO4 + PC). At negative potentials, the surface water reacts with lithium cations to form insoluble deposits of LiOH and/or LiHCO3. This reaction is irreversible. Unlike large TBA+, small Li+ cations undergo strong hydration, thereby decreasing the apparent concentration of free water in the bulk solution.