Single-atom gold species within zeolite for efficient hydroformylation

Various transition metals including Rh, Co, Ir, Ru, Os, Pt, Pd, Fe, and Ni have been proven to be efficient active centers for hydroformylation. Although Au is conventionally considered inactive for hydroformylation due to its intrinsic inertness, we design an atomically dispersed Au catalyst confined in zeolite with excellent activity and selectivity toward propene hydroformylation. The Au catalyst achieves 3,794 μmol of butyraldehyde and shows superior durability after 5 cycles, which is even comparable to Rh-based catalysts. Impregnating Au on the zeolite or increasing the mass loading of an encapsulated one will increase the size of active metal Au, which is unfavorable to hydroformylation. Detailed characterizations and theoretical calculations indicate that the isolated Au atoms within the zeolite matrix are stabilized via oxygen-bridge bonds. The formed Au1-O-SiOX motifs render maximum active site density and high structural stability, which are identified as the real active sites for efficient hydroformylation.