Conductive Cation Traps for Synthesizing Efficient and Stable Perovskite Catalysts.

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 Sr2+ 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 Sr2+ cation trap by introducing SrMoO4 during cell fabrication, which partially transforms into conductive SrMoO3 under reducing conditions. In the scenario of the high-temperature CO2 reduction reaction (HT-CO2RR), this conductive cation trap effectively prevents Sr2+ segregation in electrochemically inert SrCO3 phases, concurrently enhancing electrode conductivity and electrocatalytic activity. As a result, we demonstrate, using catalysts consisting of Pr0.90Sr0.10Co0.95Cu0.05O3-δ and 19 wt.% SrMoO4, 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.