Conductive Cation Traps for Synthesizing Efficient and Stable Perovskite Catalysts

ABSTRACT Perovskite oxides are promising material candidates for many important catalytic and energy conversion processes. Strontium doping at the A sites of perovskite oxides can potentially enhance their performance in these applications. However, the segregation of Sr 2+ to form inert phases, driven by its enrichment on surfaces, renders perovskite oxide materials unstable and inefficient during long‐term operation. Here, we design a Sr 2+ cation trap by introducing SrMoO 4 during cell fabrication, which partially transforms into conductive SrMoO 3 under reducing conditions. In the scenario of the high‐temperature CO 2 reduction reaction (HT‐CO 2 RR), this conductive cation trap effectively prevents Sr 2+ segregation in electrochemically inert SrCO 3 phases, concurrently enhancing electrode conductivity and electrocatalytic activity. As a result, we demonstrate, using catalysts consisting of Pr 0.90 Sr 0.10 Co 0.95 Cu 0.05 O 3‐δ and 19 wt.% SrMoO 4 , a one‐order‐magnitude reduction of degradation rate compared to the case without cation trapping. We report a current density of 3 A cm −2 at 1.57 V, along with near‐unity Faradaic efficiencies (FEs) for CO, energy efficiencies (EEs) exceeding 70%, and stable operation for over 160 h at 1 A cm −2 without degradation.