Cu/CuOx@C for efficient selective transfer hydrogenation of furfural to furfuryl alcohol with formic acid

Background Catalytic transfer hydrogenation has been increasingly employed as an effective and safe method for biomass upgrading; however, relying on biomass-derived formic acid (FA) as hydrogen source has rarely been studied, especially in the production of furfuryl alcohol (FOL) from biomass-derived furfural (FF) via selective hydrogenation, which is challenging due to diverse unsaturated groups. Herein, in situ encapsulation and stabilization of Cu/CuOx in a porous carbon matrix (Cu/CuOx@C) was reported for the first time and applied in the hydrogenation of FF to FOL with FA. Results Various analytical techniques were used to characterize the effect of pyrolysis temperature on Cu/CuOx@C, since the temperature can be adjusted to control the reduction of the catalyst to give different Cu-0/Cun+ ratios. The optimal catalyst Cu/CuOx@C-450 gave a 99.1% FF conversion and 98% FOL selectivity under suitable reaction conditions, exhibiting excellent activity that was even better than those of noble metal catalysts. Further, density functional theory calculations were used to reveal the effect of Cu species on FA decomposition and final catalytic performance. Conclusion The catalytic activity of Cu/CuOx@C was influenced by the pyrolysis temperature of the catalyst precursor, and its good performance was mainly attributed to a high dispersion of accessible catalytic Cu/CuOx nanoparticles on the porous carbon and to an appropriate Cu-0/Cun+ ratio. (c) 2022 Society of Chemical Industry (SCI).