Super-Exchange Interaction Induced Overall Optimization in Ferromagnetic Perovskite Oxides Enables Ultrafast Water...

Oxygen evolution reaction (OER) is crucial in many renewable electrochemical technologies including regenerative fuel cells, rechargeable metal-air batteries, and water splitting. It is found that abundant active sites with favorable electronic structure and high electrical conductivity play a dominant role in achieving high electrocatalytic efficiency of perovskites, thus efficient strategies need to be designed to generate multiple beneficial factors for OER. Here, highlighted is an unusual super-exchange effect in ferromagnetic perovskite oxide to optimize active sites and enhance electrical conductivity. A systematic exploration about the composition-dependent OER activity in SrCo_{1 x} Ru_x O_{3- δ} (denoted as SCRx) (x = 0.0-1.0) perovskite is displayed with special attention on the role of super-exchange interaction between high spin (HS) Co³⁺ and Ru⁵⁺ ions. Induced by the unique Co³⁺ -O-Ru⁵⁺ super-exchange interactions, the SCR0.1 is endowed with abundant OER active species including Co³⁺ /Co⁴⁺ , Ru⁵⁺ , and O₂ ^2- /O^- , high electrical conductivity, and metal-oxygen covalency. Benefiting from these advantageous factors for OER electrocatalysis, the optimized SCR0.1 catalyst exhibits a remarkable activity with a low overpotential of 360 mV at 10 mA cm^-2 , which exceeds the benchmark RuO₂ and most well-known perovskite oxides reported so far, while maintaining excellent durability. This work provides a new pathway in developing perovskite catalysts for efficient catalysis.