Balanced work function as a driver for facile hydrogen evolution reaction – comprehension and experimental assessment of interfacial catalytic descriptor

intermediate, is identified experimentally using in situ probing of the surface potentials of the metals, under conditions of continuous control of the humidity and the gas exposure. The derived activity trends give clear indication that the electrocatalytic activity for hydrogen evolution reaction is a consequence of an interplay between metal-hydrogen and metal-water interactions. In other words it is shown that the M-H bond formation strongly depends on the nature of the metal-water interaction. In fact, it seems that water dipoles at the metal/electrolyte interface play a critical role for electron and proton transfer in the double layer.