Co/CoO Nanoparticles with a Carbon Layer for Boosting Stability in Olefin Hydroformylation

Hydroformylation of olefins is a very important reaction process in the chemical industry. The development of efficient and stable heterogeneous Co-based catalysts is therefore of great significance. Herein, the Co/TiO2@CN catalyst was synthesized via pyrolysis of metal–organic framework (MOF) Co/NH2-MIL-125(Ti) at high temperature under a nitrogen atmosphere. The resulting catalyst exhibited not only high hydroformylation activity using cyclohexene as the substrate but also superior catalytic stability in consecutive catalytic recycles. This outstanding catalytic performance can be attributed to the electron transfer from the graphitic nitrogen in the carbon layer to Co species, which generates electron-rich active Co sites. Activity tests and characterization demonstrated that the nitrogen-doped carbon shell coating the Co/CoO nanoparticles plays a crucial role in suppressing the leaching of active Co species and enhancing catalyst recyclability. Furthermore, a reaction pathway was proposed based on the results from cyclohexene deuterioformylation.