Efficient reductive amination of furfural to furfurylamine promoted synergistically by surface Co⁰ and oxygen-vacant CoO_x

Cost-effective and environmentally friendly production of biomass-derived amines under mild conditions is highly desirable but challenging. Herein, bifunctional Co@CoO_x catalysts comprised of Co and CoO_x were prepared by controllable precipitation-reduction and adopted for furfural (FAL) reductive amination with N₂H₄. The structure of Co species can be regulated gradually via tuning reduction temperature, resulting in a significant influence on reductive amination. The optimal CoO_x-250 can achieve 96.4 % furfurylamine (FFA) yield at 60 ^◦C, and even 95.8 % at 30 ^◦C. The control experiments and DFT calculations suggest that the metal Co is responsible for H₂ dissociation and C==N reduction, while the oxygen-vacant CoO_x favors the hydrogen spillover and the C==N bond activation, thus resulting in a collaborative effort for FAL reductive amination. The catalyst is stable and versatile for various aldehydes/ketones with amine yields around 95–99 %, showing great potential for industrial application. © 2024 Elsevier Ltd. All rights reserved.