Green hydrogen - produced from water electrolysis by using sustainable electricity - is getting more attention due to its potential to be used as energy carrier as well as building block for various industrial processes. Among both half-reactions of water electrolysis, Oxygen Evolution Reaction (OER) is kinetically more challenging and it requires advances in the development of innovative electrocatalysts.
PD Dr. Harun Tüysüz (Max-Planck-Institut für Kohlenforschung), Prof. Dr. Claudia Felser (Max-Planck-Institut für Chemische Physik fester Stoffe) and co-workers have discovered a new type of OER electrocatalyst. A variety of Co2YZ type Heusler compounds with tunable physicochemical properties and well-defined topological surfaces were designed and demonstrated to effectively split water into oxygen and hydrogen. The systematic electrocatalytic investigation of the KOFO team proved a solid correlation between electron filling of d-orbitals of cobalt centers and their OER activities. The materials showed a volcano-shaped activity curve where the higher catalytic current was obtained for eg orbital filling approaching unity.
This work demonstrates proof of concept implementation of Heusler compounds as a new class of OER electrocatalysts, and the effect of orbital occupation on their catalytic performances.