B‐Site‐Metal‐Mediated Coke‐Resistant CO 2 Electrolysis on Perovskite Surfaces

Abstract High‐temperature CO 2 reduction to CO using perovskite‐oxide‐based solid oxide electrochemical cells holds promise for carbon‐neutral chemical production, yet currently faces the challenge of coke formation that leads to device failure. A key reason behind this challenge is the absence of a correlation between the coke formation mechanism and perovskite structures. Here, lanthanum strontium cobalt ferrite perovskites are taken with a classical ABO 3 structure as examples to study coke formation on them and unravel the dependence of coke resistance on the Fe stoichiometry. Lowering the Co versus Fe ratio suppresses B‐site metal exsolution, and thus, coke formation is catalyzed by these metals/alloys. Using (La 0.6 Sr 0.4 ) 0.95 Co 0.2 Fe 0.8 O 3‐δ as an example, this study reports an outlet CO pressure of 0.86 ± 0.02 atm at 800 °C, closely approaching the thermodynamic threshold for coking. The cell offers a stable outlet CO pressure of ≈0.8 atm in 320‐h electrolysis at 220 mA cm −2 and the potential to build a high‐performance tandem system for efficient electrosynthesis of multi‐carbon products from CO 2 .