Structure–Activity Relation of the Oxide Path Mechanism for O–O Coupling on Rutile-Based Oxygen Evolution Reaction Catalysts

The advancement of acid-stable oxygen evolution reaction (OER) electrocatalysts is crucial for efficient hydrogen production through proton-exchange membrane water electrolysis. Unfortunately, the OER activity of the electrocatalyst is constrained by a linear scaling relation in the adsorbate evolution mechanism (AEM), while the lattice oxygen mechanism (LOM) undermines stability. The emerging oxide path mechanism (OPM) via direct O–O coupling would benefit the design of highly active and stable OER catalysts by circumventing oxygen defect formation featured in the LOM. Herein, by systematic computational analysis of the OPM, we discover a linear scaling relation between the O–O coupling barrier (E_a) and binding energies of 2O* [ΔE_b(2O*)], which results in the identification of the Sabatier volcano for the activity of the O–O coupling in the OPM using ΔE_b(2O*) as the descriptor. This proposed theoretical structure–activity relation makes it possible to analyze the activity trend of OPM-driven electrocatalysts in a general way. Our work not only deepens the mechanistic understanding of OPM but also provides a rational basis for designing high-performance OPM-driven OER electrocatalysts.