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 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 Pr_0.90Sr_0.10Co_0.95Cu_0.05O_3-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.