Modulating the covalency of Ru-O bonds by dynamic reconstruction for efficient acidic oxygen evolution.

Developing ruthenium-based oxide catalysts capable of suppressing lattice oxygen participation in the catalytic reaction process is crucial for maintaining stable oxygen evolution reaction (OER) under acidic conditions. Herein, we delicately construct a RuO nanoparticle-anchored LiCoO nanosheet electrocatalyst (RuO/LiCoO), achieving dynamic optimization of RuO during the reaction process and improving catalytic stability. Benefiting from the unique electrochemical delithiation characteristics of the LiCoO support, the covalency of the Ru-O bond is effectively regulated during the OER process. The weakened Ru-O covalent bond inhibits the participation of lattice oxygen in the catalytic reaction and ensures the continuous operation of the Ru active sites. Moreover, the extended Ru-O bond in the optimized RuO/LiCoO catalyst reduces the formation energy barrier of the *OOH intermediates, accelerating the progress of the OER. As a result, the RuO/LiCoO catalyst requires only an overpotential of 150 ± 2 mV at 10 mA cm in 0.5 M HSO and operates stably for 2000 h at 1 A cm in a proton exchange membrane water electrolysis. This work opens new avenues for designing efficient ruthenium-based catalysts.