Perspective—A New Viewpoint on the Mechanism of the Hydrogen Evolution Reaction on Various Transition Metal Electrodes

Abstract

In the research for the catalytic activity of metals, the electronegativity (EN) and valence electronic configuration (VEC) of the atoms of metals have been considered as important factors. By comparing the catalytic activity of the hydrogen evolution reaction (HER) from various metals, we find that metals with high EN and containing two or more accessible partially filled orbitals (PFOs) can support high exchange current density i 0,H(A cm−2) for HER, however, metals with low EN and/or with just one or no PFOs are unable to support high i 0,H values. It is, therefore, concluded that the EN and the PFOs of the atoms of metals plays a decisive role in its catalytic behavior. Here, the EN and the VEC of the atoms of transition metals in relation to the catalytic activation for HER is discussed and a new type of reaction mechanism of HER on various metal electrodes is also suggested.