Redox-manipulated RhO x 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 Sr2Fe1.45Rh0.05Mo0.5O6-δ (SFRhM) perovskite surface with a high density of 36,000 µm-2. Compared with non-uniformly distributed RhO x nanoparticles on Sr2Fe1.5Mo0.5O6-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.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 Sr2Fe1.45Rh0.05Mo0.5O6-δ (SFRhM) perovskite surface with a high density of 36,000 µm-2. Compared with non-uniformly distributed RhO x nanoparticles on Sr2Fe1.5Mo0.5O6-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 th