The acceleration of the hydrogen evolution reaction from acid solutions by sulfur compounds. Part I. Mercury electrode

Thiourea and N-substituted thioureas are found to accelerate the HER at the mercury electrode. The effects increase with increasing substitution on the N-atom while the effects are absent on substitution on the S-atom. The observations are explained on the basis of a faster discharge of a protonated thiourea. Semi-quantitative corrections for the variation of the Tafel slopes in the presence of the thioureas are made. © 1984 Elsevier Sequoia S.A.