Constructing Magnetic Single-Atom Catalysts with High Activity and Stability via an in situ Nitrogen Doping Modulation Strategy for the Hydroformylation of 1-Dodecene

Abstract

Regulating the hydroformylation capacity of heterogeneous catalysts is essential for efficiently converting higher olefins into aldehydes. In this study, a magnetic single-atom rhodium-cobalt-based catalyst (RhCo SACs) was synthesised by modifying Fe₃O₄ with polymerised carbon nitride. Maintaining a constant metal single-atom loading, the catalytic activity in 1-dodecene hydroformylation was modulated by adjusting the type of N species in the support. The distribution of single atoms and valence states was characterised. At the same time, density functional theory (DFT) calculations were conducted to evaluate substrate binding energies and reaction-free energy barriers, providing insights into reaction mechanisms and pathways. The RhCo-pyridinic N configuration lowered the Gibbs free energy of the rate-determining and hydrogenation steps, enhancing substrate reaction activity. Compared to RhCo-graphitic N, RhCo-pyridinic N demonstrated superior performance, achieving a 1-dodecene conversion rate of 98.3% and aldehyde selectivity of 98.6%. Furthermore, the catalyst was magnetically recovered without loss of activity or mass and maintained stable performance over 10 reuse cycles. These findings present a novel and efficient strategy for the precise design of magnetic single-atom catalysts with potential practical applications in the hydroformylation of high-carbon olefins.