Surface Activation by Single Ru Atoms for Enhanced High‐Temperature CO2 Electrolysis

Abstract Cathodic CO 2 adsorption and activation is essential for high‐temperature CO 2 electrolysis in solid oxide electrolysis cells (SOECs). However, the component of oxygen ionic conductor in the cathode displays limited electrocatalytic activity. Herein, stable single Ruthenium (Ru) atoms are anchored on the surface of oxygen ionic conductor (Ce 0.8 Sm 0.2 O 2‐δ , SDC) via the strong covalent metal‐support interaction, which evidently modifies the electronic structure of SDC surface for favorable oxygen vacancy formation and enhanced CO 2 adsorption and activation, finally evoking the electrocatalytic activity of SDC for high‐temperature CO 2 electrolysis. Experimentally, SOEC with the Ru 1 /SDC‐La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3‐δ cathode exhibits a current density as high as 2.39 A cm −2 at 1.6 V and 800 °C. This work expands the application of single atom catalyst to the high‐temperature electrocatalytic reaction in SOEC and provides an efficient strategy to tailor the electronic structure and electrocatalytic activity of SOEC cathode at the atomic scale.