“…The PDS reduction begins with a dissociative chemisorption step. ,,,, The adsorptive dissociation S 2 O 8 2– forms two adsorbed SO 4 – , each blocking up to three surface sites denoted as (SO 4 – ) ad , namely where * A denotes adsorption sites for (SO 4 – ) ad , and k f and k b denote the rate constants of the forward and backward reactions of the first dissociative chemisorption step, respectively. In this model, we distinguish adsorption sites for (SO 4 – ) ad and those for adsorbed hydroxyl (OH ad ), and experiments have proved the absence of site-blocking effect of OH ad on PDS reduction at Pt(111) …”