Phosphorylation of nitrogen-doped carbon stabilizes Rh clusters for selective hydroformylation of alkenes to linear aldehydes

Abstract

Hydroformylation of olefins to produce high-value aldehydes is among the most important processes in the chemical industry. However, heterogeneous hydroformylation catalysts still face major challenges, including limited selectivity toward linear aldehydes, low catalytic activity, and poor stability. In this study, we developed a phosphorylation strategy to synthesize a hollow phosphorus- and nitrogen-codoped carbon material encapsulating Rh nanoclusters as a confined catalyst (Rh-CNP). The incorporation of phosphorus induces a significant electronic effect that enhances selectivity in alkene hydroformylation, achieving a linear-to-branched aldehyde ratio above 7. Mechanistic analysis shows that the formation pathway for linear aldehydes has a lower energy barrier, resulting in a selectivity of 87.8% in the hydroformylation of 1-octene. Furthermore, the spatial confinement structure significantly improves catalyst stability, maintaining consistent performance over ten reaction cycles. The one-pot synthesis of the Rh-CNP catalyst through in situ phosphorylation enables precise control of phosphorus content and offers new insights into the selective hydroformylation of alkenes as well as the design of highly stable confined catalytic systems.