Mo ₂ C Morphology Dependence in Co–Mo ₂ C Interface Structure Evaluation for Boosting α-Olefin Hydroformylation

The hydroformylation of high-carbon α-olefins is a pivotal industrial process. Still, heterogeneous Co-based catalysts suffer from low activity and Co leaching due to strong coordination of CO to Co atoms. Herein, we address the dynamic evolution and active structure of Co species by interacting Co nanoparticles or ultrahigh-dispersed clusters with β-Mo2C nanoparticles (Co-30Mo2Cparticle/CNF) and nanofilms (Co-100Mo2Cfilm/CNF) on carbon nanofibers. The specific activity in the formation of heptanal from 1-hexene hydroformylation increased by 10.7 times on Co-30Mo2Cparticle/CNF (21.4 molheptanal/molCo/h) and 2.4 times on Co-100Mo2Cfilm/CNF (4.7 molheptanal/molCo/h) compared with Co/CNF (2.0 molheptanal/molCo/h). Moreover, Co-100Mo2Cfilm/CNF exhibits enhanced stability with only 1.7% Co leaching. The Mo2C nanoparticles interact with Co nanoparticles, oxidizing them to form highly active Co-MoOx sites with a lower CO insertion barrier. The reaction environment influences the structural evolution of the Co-MoOx interaction. In contrast, Mo2C nanofilms form robust Co–C and Co–Mo bonds at the Co–Mo2C interface, stabilizing atomically distributed Co clusters against leaching. This work establishes a morphology-driven strategy to control the dynamic interaction of Co and additives, thereby decoupling activity and stability in heterogeneous catalysis for hydroformylation.