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

Abstract

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 i0,H(A cm - 2 ) for HER. However, metals with low EN and/or with just one or no PFOs are unable to support high i0,H values. It is concluded that the EN and PFOs of the metal atoms play a decisive role in catalytic behavior. EN and VEC of the atoms of transition metals in relation to catalytic activation for HER is discussed and a new type of reaction mechanism of HER on various metal electrodes is suggested