Hydrogen evolution reaction on vanadium, chromium, manganese, cobalt

The electrolytic hydrogen evolution reaction (HER) has been studied on V, Cr, Mn, and Co in sulfuric acid‐sulfate solutions. The data consist of Tafel slopes, exchange current densities, apparent heats of activation, corrosion rates, corrosion potentials, and, in some cases, reaction order derivatives. Attempts were also made to obtain information on the electrode coverage by transient techniques. The presence of corrosion, however, makes the possible electrode coverage by adsorbed hydrogen inaccessible. By combining these electrode kinetic data with the gas‐phase hydrogen adsorption behavior of these metals, it is suggested that the HER proceeds by means of the initial discharge mechanism on V and Mn whereas on Cr and Co, the radical‐ion mechanism has been concluded.