Boosting the Hydroformylation Activity of a Rh/CeO₂ Single-Atom Catalyst by Tuning Surface Deficiencies

Controlling the interactions between atomically dispersedmetalatoms and the support plays significant roles in determining the activityand selectivity of single-atom catalysts. In this report, we tunedthe local coordination environment of Rh single atoms on CeO2 via calcination to construct a highly active hydroformylation catalyst.Single-atom Rh/CeO2 calcined at a high temperature exhibitsmore oxygen vacancies, which lead to the formation of a large amountof low-coordination Rh active species that are more active for hydroformylation.Under the optimum conditions, the best Rh/CeO2 catalystachieved a TOF at approximately 5000 h(-1) with 100%aldehyde selectivity in propylene hydroformylation to butanal. Insitu FTIR spectroscopy and in situ XPS characterizations provide strongevidence that Rh on 800 degrees C-calcined CeO2 is easilyactivated to form surface HRh-(CO)(2) active species, favoringpropylene adsorption and CO insertion. This work highlights the significanceof engineering metal-support interactions in tuning the hydroformylationperformance of single-atom catalysts and contributes to mechanisticinsights into single-atom Rh-catalyzed hydroformylation reactions.