Rational dual-state silver modulation in perovskite oxides enabling advanced water oxidation electrocatalysis

Perovskite oxides have garnered considerable attention as promising electrocatalysts for the oxygen evolution reaction (OER) owing to their economic viability, structural tunability, and robust stability. Nevertheless, their intrinsically sluggish kinetics of OER severely limits the overall efficiency of electrocatalytic water splitting. This challenge underscores the urgent need to further optimize perovskite catalysts toward faster reaction kinetics and reliable long-term operation. To this end, a silver-modified perovskite oxide, Sr_0.9Ag_0.1Co_0.7Fe_0.3O_3-δ (SACF10), is strategically designed through introducing Ag into the A-site to enhance electrocatalytic performance. Notably, silver species in SACF10 coexist as Ag⁺ ions incorporated into the lattice and metallic Ag nanoparticles dispersed on the surface, forming a synergistic dual-state configuration that enhances oxygen vacancy formation and accelerates charge transport. As a result, SACF10 outperforms the pristine SrCo_0.7Fe_0.3O_3-δ and other Ag-modified compositions in terms of intrinsic activity, mass activity, and long-term durability, thereby highlighting its superior catalytic characteristics. Furthermore, its practical applicability is validated through overall water splitting tests in a two-electrode configuration, where the assembled electrolyzer exhibits excellent activity and operational stability. This work establishes a promising strategy for OER catalyst design by leveraging the synergistic interplay between ionic and metallic silver species within perovskite frameworks, thereby providing new insights into the rational construction of multi-state active centers for advanced electrocatalysis.