The effect of temperature on the potentiodynamic behaviour of Ir in 3.7 M H2SO4 was studied in the range 293-195 K. At 293 K, voltammograms are close to Chose reported for Ir in dilute acids,but no activation for hydrous oxide growth was observed. The H atom potential range exhibits weakly and strongly bound H adatom species. Slow and fast kinetic contributions can be distinguished by applying conventional and triangular modulated voltammetry, respectively. The weakly H adatom electrosorption reactions behave as reversible processes even in the frozen electrolyte while the kinetics of strongly bound species is influenced by a competitive adsorption probably involving sulphate ions. This effect becomes more remarkable as the temperature is diminished, Reversible processes involving H adatom and O-containing Species in Ir oxide layers are explained in terms of fast charge transfer accompanied by fast proton motion processes at the interface.