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

Abstract

Controlling the interactions between atomically dispersed metal atoms and the support plays significant roles in determining the activity and selectivity of single-atom catalysts. In this report, we tuned the 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 exhibits more oxygen vacancies, which lead to the formation of a large amount of low-coordination Rh active species that are more active for hydroformylation. Under the optimum conditions, the best Rh/CeO2 catalyst achieved a TOF at approximately 5000 h–1 with 100% aldehyde selectivity in propylene hydroformylation to butanal. In situ FTIR spectroscopy and in situ XPS characterizations provide strong evidence that Rh on 800 °C-calcined CeO2 is easily activated to form surface HRh(CO)2 active species, favoring propylene adsorption and CO insertion. This work highlights the significance of engineering metal–support interactions in tuning the hydroformylation performance of single-atom catalysts and contributes to mechanistic insights into single-atom Rh-catalyzed hydroformylation reactions.