Entropy‐Driven Spin Transition in Rare Earth Perovskites Enables Feedback Adsorption for Enhanced Acidic Water Oxidation

ABSTRACT Modulating catalytic reaction pathways and site reaction behaviors to break the activity/stability trade‐off poses significant challenges for the acid oxygen evolution reaction (OER). Herein, a sol‐gel method is proposed to prepare high entropy rare earth (HERE) perovskite oxides HERECoO 3 /RuO 2 (RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) for pH‐universal OER for the first time. (LaPrNdSmEu)CoO 3 /RuO 2 achieves a current density of 10 mA cm −2 for OER with overpotentials of only 115 mV and operates stably over 1000 h at 0.1 A cm −2 under the acidic condition. Experimental results indicate that the novel spin regulation‐lattice oxygen mechanism (SR‐LOM) induces a shift in the OER mechanism from the adsorption evolution mechanism (AEM) to LOM, and promotes the spin state transition of Co to optimize intermediate adsorption. Theoretical calculations have confirmed that the high entropy strategy has induced stronger interactions at the heterointerface, which not only accelerates the electron transfer but also promotes the electroactivity of the surface. Moreover, the lattice oxygen becomes more flexible in HERECO 3 /RuO 2 , enabling the LOM process to promote the superior OER with reduced energy barriers. Our findings provide a new way for the rational design of highly active RE‐based electrocatalysts.