Lattice-locked CeRu solid solution with Ru-O-Ce motifs suppresses Ru dissolution for enhanced alkaline oxygen...

Ruthenium dioxide (RuO₂) shows highly activity toward the alkaline oxygen evolution reaction (OER). However, the practical application is severely limited by rapid degradation caused primarily by the dissolution of active Ru sites under harsh oxidizing conditions. In this work, we report a series of atomically designed cerium‑ruthenium solid-solution oxides (Ce_xRu_1-xO₂) that fundamentally suppresses Ru leaching by highly dispersed Ru-O-Ce motifs, fabricated via a combination of flame-assistant colloid-mediated combustion and etching methods. The rapid combustion synthesis generates an instantaneous high-temperature environment and rapid energy release, which kinetically suppress Ru atom segregation and lock them uniformly within the CeO₂ lattice. Moreover, the usage of SiO₂ templates ensures the uniform dispersion of reactants on the NF substrate, guaranteeing a consistent combustion process that yields homogeneous and porous oxides. Owing to its uniform porous structure and the electronic modulation enabled by highly dispersed Ru-O-Ce motifs, the Ce_0.6Ru_0.4O₂/NF catalyst exhibits both outstanding OER activity (η₁₀ = 224 mV) and robust stability in 1 M KOH, with only trace amounts of Ru leaching into the electrolyte. DFT calculations reveal that the strong d-p and d-d orbital couplings in the solid-solution oxide lowers the energy barrier of the OER rate-determining step, while the robust Ru-O-Ce bridging interactions concurrently suppress the over-oxidation of Ru. This work presents a lattice locking approach to effectively enhance the catalytic activity and durability of Ru-based oxides, outlining a viable design pathway for future catalyst development.