Redox-manipulated RhOx nanoclusters uniformly anchored on Sr2Fe1.45Rh0.05Mo0.5O6–δ perovskite for CO2 electrolysis

The sluggish reaction kinetics of CO₂ electroreduction in perovskite-based cathodes severely limits the efficiency of solid oxide electrolysis cells (SOECs). The construction of the high-density active sites on the perovskite surface is crucial for promoting CO₂ electrolysis in SOEC. In this study, we explore a redox-induced redispersion strategy to produce RhO_x nanoclusters uniformly anchored on a Sr₂Fe_1.45Rh_0.05Mo_0.5O_6–δ (SFRhM) perovskite surface with a high density of 36,000 µm⁻². Compared with non-uniformly distributed RhO_x nanoparticles on Sr₂Fe_1.5Mo_0.5O_6–δ (RhO_x/SFM) prepared by a conventional impregnation process, the successive reduction and oxidation treatment first exsolves the highly dispersed RhFe alloy nanoparticles on SFRhM and then selectively dissolves the iron species in the RhFe alloy nanoparticles into the bulk of SFRhM, resulting in fully exposed RhO_x nanoclusters uniformly anchored on the SFRhM surface (RhO_x@SFRhM). Electrochemical measurements and density functional theory calculations indicate that the high-density RhO_x@SFRhM interfaces promote CO₂ adsorption and activation during CO₂ electrolysis, thus leading to improved electrocatalytic activity and stability compared to that of its SFRhM and RhO_x/SFM counterparts.