Selective conversion of lignocellulosic biomass and its components into value-added furans over Al-based bimetals: Analytical Py-GC × GC/MS

Abstract

Furans is a versatile chemical family, developing environmental-friendly methods to prepare furans and enhance the selectivity of high-value furans are of great significance. In present study, bio-based activated carbon supported Al-containing bimetals were devised to serve as solid acid catalysts for selective transformation lignocellulosic biomass and its components into valuable furans. Among the bimetallic catalysts, 2Al-4Zr/AC increased both the content of furans and the selectivity of 5-methylfurfural (5-MFF) , and the highest peak area% of furans and selectivity of 5-MFFwere 88.6% and 44.5%, which were derived from the catalytic pyrolysis of glucose, and the counterparts from the catalytic pyrolysis of pine wood were 56.3% and 30.7%, respectively. In addition to 5-MFF, 2-methylfuran (2-MF), furfural (FF) and 2,5-dimethylfuran (DMF) were also included into major furans. In the catalytic pyrolysis process of lignocellulosic biomass, C6-based sugars were conducive to the production of 5-MFF, and C5-based sugars favored the formation of 2-MF and FF. Characterization with NH3-TPD, Pyridine-IR, N2 adsorption-desorption, XRD and XPS indicated that 2Al-4Zr/AC, with mild Lewis acidity and combined Brønsted acid sites, high surface area and micro-mesoporous structure, promoted both the dehydration of saccharides and the dehydrogenation of cyclopentanones to increase the content of furans. In the catalyst, the synergistic effect between Al species (including Al2O3, AlO(OH) and Al(OH)3) and Zr species (mainly ZrO2) played an important role in its catalytic activity, and Al species were the major contributor to its activity.