Lignin-assembled zirconium-based PNA nanofiber for the catalytic transfer hydrogenation of furfural into furfuryl alcohol

Lignin is a highly abundant biopolymer next to only cellulose, and its transformation into high value-added products is always of interest. It is well known to contain bounteous hydroxyl groups, which can act as natural organic ligands to assemble metal catalysts. Herein, lignin was selected to assemble well-dispersed Zr nanoparticles in polyacrylonitrile nanofiber by electrospinning technology (ZrNPs-lignin/PAN). Systematic characterizations revealed that lignin promoted the coordination between zirconium ions and PAN nanofibers to generate Lewis acid and Lewis base sites. The abundant Lewis acid-base sites confer the composite with remarkable catalytic activity in the transfer hydrogenation (TH) of furfural (FAL) into furfuryl alcohol (FOL), and a quantitative yield of 95.9% with a high TOF of 15.1 h(-1) was obtained under mild conditions. ZrNPs-lignin/PAN exhibited good recycling stability and excellent universality in the CTH of a diverse array of carbonyl chemicals into their corresponding products.