ADVANCES IN ELECTROCATALYSIS FOR HYDROGEN EVOLUTION IN THE LIGHT OF THE BREWER-ENGEL VALENCE-BOND THEORY.

The Brewer-Engel valence-bond theory for bonding in metals and intermetallic phases has been employed to correlate the electrocatalytic features of both individual and composite transition metal catalysts for the hydrogen evolution reaction (h. e. r. ). The basic concept of the Brewer-Engel valence-bond theory, which relates the electronic state of lowest energy level or the structure of atoms, with the corresponding phase structure in both individual metallic and multicomponent intermetallic systems, is also given. The theoretical explanation for an optimal (d**8) electronic configuration in both individual and composite synergetic electrocatalytic systems is given and compared with similar catalytic processes. The induced hydridic feature of high activity synergetic transition metal composite electrocatalysts is also pointed out.