Hydrogen evolution reaction from EDTA solutions

Abstract

An attempt was made to investigate the mechanism and kinetics of hydrogen evolution reaction on zinc and platinum wire electrodes from solutions containing ethylene diamine tetraacetic acid (EDTA). EDTA is a tetra-basic acid whose dissociation covers a wide range of pH, with a betaine structure in solutions. Introduction of EDTA into the solution provided several species whose dissociative hydrogen could be a source of h.e.r. The effect of EDTA concentration and pH on the Tafel dependence of cathode process was studied by galvanostatic method and cyclic voltametry. The aim was to establish the effect of EDTA on hydrogen evolution at the electrodes, i.e. whether evolution of hydrogen proceeds via hydronium ions arising from dissociation of EDTA, EDTA anions or hydrogen atoms transferred to the metal from EDTA molecules, as well as the impact of the Rowland effect on h.e.r.