Selective conversion of lignocellulosic biomass into furan compounds using bimetal-modified bio-based activated carbon: Analytical Py-GC×GC/MS

Abstract

Bio-based activated carbon supported Cu, Al, Sn and their bimetals were devised to serve as solid acid catalysts for the pyrolysis of xylan to generate furan compounds, and their catalytic activity was evaluated by Py-GC × GC/MS. The Cu–Al/C catalysts with diverse Cu to Al ratios exhibited better performance in enhancing the content of furans and the selectivity of 2-MF compared with other catalysts. Among the series of Cu–Al/C catalysts, 4Cu–2Al/C achieved a content of furan compounds as high as 80.6%, and 2-MF, FF and furan were the major furan products with selectivity values of 44.0%, 30.0% and 15.8%, respectively. Furthermore, the catalyst also worked well in promoting the pyrolysis of xylose, glucose, cellulose and pine to produce furans, and the highest and lowest contents of furans were obtained from glucose (87.8%) and pine (70.1%), respectively. These results suggest the 4Cu–2Al/C obviously promotes the formation of furans, which is comparable to those of recently reported solid acid catalysts. Characterization with XRD, XPS, NH3-TPD, N2 adsorption-desorption, and SEM, demonstrated that the effective interactions between Cu species and Al species facilitated the dehydration of saccharides and the dehydrogenation of cyclopentanones to increase furan compounds. Al species, mainly Al2O3 were the major contributor to the Lewis acid sites, and Cu specie played an essential role in regulating the acidity and enhancing the selectivity of 2-MF. In addition to furans, 4Cu–2Al/C was found to have positive effects on hindering the formation of acids in the pyrolysis products.