Dynamic Interplay between Copper Tetramers and Iron Oxide Boosting CO₂ Conversion to Methanol and Hydrocarbons under Mild Conditions

Atomically precise subnanometer catalysts are of significant interest because of their remarkable efficiency in a variety of catalytic reactions. However, the dynamic changes of active sites under reaction conditions, in particular, the transition of cluster–oxide interface structure have not yet been well-elucidated, lacking in situ measurements. By using multiple state-of-the-art in situ characterizations, here we show a dynamic interplay between copper tetramers and iron oxides in a single-size Cu₄/Fe₂O₃ catalyst, yielding an enrichment of surface Cu₄–Fe²⁺ species under reaction conditions that boosts CO₂ hydrogenation at near-atmospheric pressures. During reaction, Cu₄ clusters facilitate the reduction of Fe₂O₃ producing surface-rich Fe²⁺ species in the proximate sites. The as-formed Fe²⁺ species in return promotes CO₂ activation and transformation over Cu₄ cluster, resulting in strikingly high methanol synthesis at low temperatures and C₁/C₃ hydrocarbon production in a high-temperature regime. The discovery of highly active Cu₄–Fe²⁺ sites thus provides new insights for the atomic-level design of copper catalyst toward high-efficiency CO₂ conversion under mild conditions.