Fermi dynamics and the Brewer structural bonding factors have been employed to define synergism and electrocatalytic properties for hydrogen electrode reactions upon individual transition metals and their hypo-hyper-d-electronic combinations of intermetallic phases. It has clearly been shown and pointed out that electrocatalysis and its synergetic effect appear as the interionic interaction of hypo-hyper-d-electronic components either within metallic lattice, or upon the substrate surface. The induced external polarization or non-Faradaic (NEMCA) effect upon the electronic density of states and thereby advanced overall (electro)catalytic activity has been correlated with the basic catalytic properties and emphasized, too.