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

Cost-effective and environmentally friendly production of biomass-derived amines under mild conditions is highly desirable but challenging. Herein, bifunctional Co@CoOx catalysts comprised of Co and CoOx 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 CoOx-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 CN reduction, while the oxygen-vacant CoOx favors the hydrogen spillover and the CN 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.