Electrochemical deprotonation of phosphate on stainless steel

S. da Silva (1) , Régine Basséguy (1) , Alain Bergel (1)

1 LGC - Laboratoire de Génie Chimique

Voltammetric experiments performed in phosphate buffer at constant pH 8.0 on platinum and stainless steel revealed clear reduction currents, which were correlated to the concentrations of phosphate. On the basis of the reactions proposed previously, a model was elaborated, assuming that both H2PO4 and HPO4 2 underwent cathodic deprotonation, and including the acid–base equilibriums. A kinetic model was derived by analogy with the equations generally used for hydrogen evolution. Numerical fitting of the experimental data confirmed that the phosphate species may act as an efficient catalyst of hydrogen evolution via electrochemical deprotonation. This reaction may introduce an unexpected reversible pathway of hydrogen formation in the mechanisms of anaerobic corrosion. The possible new insights offered by the electrochemical deprotonation of phosphate in microbially influenced corrosion was finally discussed.

Mots clés: Steel; Phosphate; Modelling; Hydrogen evolution; Microbially influenced corrosion

Domaines: Catalyse

S. da Silva, Régine Basséguy, Alain Bergel. Electrochemical deprotonation of phosphate on stainless steel. Electrochimica Acta, 2004, 49 (26), pp.4553-4561. ⟨10.1016/j.electacta.2004.04.039⟩. ⟨hal-00450157⟩