Perovskites for CO 2 Conversion: Active‐Phase Identity, Reconstruction, and the Evidence Behind Mechanistic Claims

Converting CO 2 into fuels and chemicals is a central challenge in sustainable chemistry. Perovskites offer compositional flexibility, tunable band structures, redox‐active B‐site cations, controllable defect chemistry, and a propensity for exsolution and surface reconstruction under operating conditions. This review critically synthesizes perovskite‐based CO 2 conversion across halide and lead‐free halide perovskites; Cu‐ and Fe‐substituted systems; oxynitrides and oxyfluorides; and thermochemical, chemical‐looping, solid oxide electrolysis, and methanation oxides. Using an evidence hierarchy that prioritizes 13 CO 2 isotope labeling, operando spectroscopy, local structure probes, and postreaction characterization, the analysis distinguishes established active‐site claims from activity correlations, identifies systems whose working catalyst is a reconstructed phase rather than the as‐synthesized perovskite, and outlines the standards needed for mechanism‐guided catalyst design.