Developing highly efficient oxygen evolution reaction electrocatalysts by electronic structure regulation on transition metal oxides

The efficiency of rechargeable metal-air battery, water electrolysis systems, solar fuels devices is limited by the oxygen evolution reaction (OER) due to its sluggish kinetics. For the OER process, it not only involves four sequential proton coupled electron transfers, but also includes a spin state transition from the spin singlet state of OH-/H2O to the spin triplet state of O2 production. Considering this kind of spin state transition is quantum forbidden, it needs to associate an active catalyst with specific spin configurations to lower the energy consumed to promote such spin transition as well as the charge transfer. While the spin configuration of transition metal based OER electrocatalysts, is strongly coupled with other fundamental parameters, such as charge, orbital, and lattice, and they determine the outward manifested properties all together. Therefore, to understand the true mechanism of OER is to identify the roles of spin and clarify its correlations with other intrinsic parameters.