Molecular fence Cu-based catalyst for CO2 hydrogenation to CO with high activity and durability

The conversion of CO2 into high-value syngas (CO and H2) using Cu-based catalysts has garnered considerable interest. However, these catalysts deactivate rapidly due to Ostwald-ripening and thermal aggregation. Herein, we propose to encapsulate Cu-cluster into mMOR zeolite for engineering a separation-site catalyst Cu@mMOR. In the reverse water-gas shift reaction (RWGS), mMOR zeolite of Cu@mMOR directly captures and then activates CO2, and simultaneously serves as a molecular fence to prevent CO2 contact with Cu-clusters surrounding with small pore of mMOR (<3.0 Å) channels. These encapsulated Cu-clusters in mMOR possess considerable Cu vacancies, which significantly facilitate H2 heterolytic dissociation, transferring H* species towards activated CO2 on mMOR and converting them into CO. This separation-site strategy efficiently increases catalytic activation while intelligently altering the CO2 reaction pathway, preventing Cu from thermal agglomeration and Oswald ripening in the catalyst. Consequently, Cu@mMOR attains a space-time yield of CO as high as 3290 mmol gcat-1 h-1, with catalytic stability extending up to 788 hours. Turning CO₂ into useful fuels is promising but catalysts often quickly clump and fail. Here, Cu clusters trapped inside a porous zeolite guide hydrogen to activated CO₂ while staying stable, delivering long term, high CO output.