A-site cations in stannate perovskites affect their performance in catalysing CO₂ electroreduction

Stannate perovskites (MSnO₃), benefiting from their high production of HCOOH and the perovskite structure-enabled tunability of properties, are emerging as promising catalysts for electrochemical CO₂ reduction (CO₂R). However, optimizing the catalytic performance of MSnO₃ for CO₂R remains largely unexplored. Here, we systematically study the catalytic performance of MSnO₃ with a distinct A-site cation, M (M = Ba, Sr, and Ca), for CO₂R. Our experimental results show that the M cation dramatically affects the catalytic performance, especially the selectivity and stability. In particular, the CaSnO₃-based catalyst exhibits the highest selectivity to HCOOH and stability but the lowest activity. Further theoretical investigations reveal that the A-site cation can affect the selectivity of MSnO₃ for the CO₂R reaction and may impact the stability of MSnO₃. Both experimental and theoretical findings reveal that stannate perovskites can be effective and selective catalysts for CO₂R, while their stability needs to be considered carefully. These results should shed light on the rational design of perovskite catalysts with desired performance for CO₂R.