The From these observations we can develop a new HOR/HER mechanism: First, (3) suggests a T-V type mechanism (illustrated in Fig. ), however as to (4), the coverage of the hydrogen intermediate must be unbound to explain how no kinetically limiting current is observed which justifies using the coverage expression developed in (1) to account for the lacking bound in H-upd. Secondly, the rate constant of the Volmer step depends on the pH as derived from the kinetic analysis of the H-upd peaks 1 and 2 (Fig. ).