Influence of the Ionic Strength and the Nature of Supporting Electrolyte on Electrooxidation of Formaldehyde at Pt and Cu

Rasa Pauliukaite* and Eugenijus Norkus
Department of Catalysis, Institute of Chemistry, A. Go{tauto 9, LT-01108 Vilnius, Lithuania
E-mail: rasa@chi.lt

Abstract
The electrooxidation current of methanediol (hydrated formaldehyde) at polycrystalline Pt and Cu decreases with increase in the ionic strength of the solution at constant pH values but increases with increase in pH and formaldehyde concentration. A linear dependence between the oxidation current and the concentration of methanediol anion is obtained, whereas, a non linear dependence is observed between the oxidation current and the total concentration of formaldehyde. The optimum conditions for formaldehyde oxidation were observed when NaNO₃, Na₂SO₄, and K₂SO₄ were used as supporting electrolytes in the pH range down to 13.0 and the ionic strength up to 0.5 mol L^–1.

Keywords: Formaldehyde, methanediol, anodic oxidation, ionic strength, cyclic voltammetry.