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 Cu-4/Fe2O3 catalyst, yielding an enrichment of surface Cu-4-Fe2+ species under reaction conditions that boosts CO2 hydrogenation at near-atmospheric pressures. During reaction, Cu-4 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 C-1/C-3 hydrocarbon production in a high-temperature regime. The discovery of highly active Cu-4-Fe2+ sites thus provides new insights for the atomic-level design of copper catalyst toward high-efficiency CO2 conversion under mild conditions.