The kinetics of iron electrodeposition from acid sulphate solutions onto a platinum electrode was investigated by means of stationary polarisation curves and electrochemical impedance spectroscopy. Together with interfacial pH data previously obtained. the effect of pH was analysed. The formation of at least three adsorbed intermediates at the cathode surface was evidenced in all pH values. The relative rate of their formation and its Surface concentration depend on the solution pH as well as on the electrode potential. It is suggested that two of these species catalyses the H+ reduction whereas the other one may have a blocking effect oil this reaction. (C) 2008 Elsevier Ltd. All rights reserved.