High production of furfural by flash pyrolysis of C6 sugars and lignocellulose by Pd-PdO/ZnSO4 catalyst

Furfural is an important platform chemical for the synthesis of next-generation bio-fuels. Here the authors report a novel heterogeneous catalyst, Pd-PdO/ZnSO4, for the mass production of furfural from catalytic flash pyrolysis of lignocellulosic biomasses. Furfural (C5H4O2) is an important platform chemical for the synthesis of next-generation bio-fuels. Herein, we report a novel and reusable heterogeneous catalyst, Pd-PdO/ZnSO4 with 1.1 mol% palladium (Pd), for the production of furfural by flash pyrolysis of lignocelluloses at 400 degrees C. For both dry and wet C6 cellulose and its monomers, the furfural yields reach 74-82 mol%, relative to 96 mol% from C5 xylan and 23-33 wt% from sugarcane bagasse and corncob. The catalyst has a well-defined structure and bifunctional property, comprising a ZnSO4 support for the dehydration and isomerization of glucose, and a local core-shell configuration for metallic Pd-0 encapsulated by an oxide (PdO) layer. The PdO layer is active for the Grob fragmentation of formaldehyde (HCHO) from glucose, which is subsequently in-situ steam reformed into syn-gas (i.e. H-2 and CO), whereas the Pd-0 core is active in promoting the last dehydration step for the formation of furfural.