Catalytic upgrading of xylan-based hemicellulose pyrolysis vapors over activated carbon supported Pt-based bimetallic catalysts to increase furans: Analytical Py-GC × GC/MS

摘要

Catalytic pyrolysis of xylan-based hemicellulose over Pt-based bimetallic catalysts supported by activated carbon using Py-GC x GC/MS was carried out to improve the formation of furan compounds. Prior to the experiments, effects of pyrolysis temperature, catalytic temperature, reaction time and catalyst amount on furans production were examined thoroughly. Based on the optimal operation parameters, all of the Pt-based bimetallic catalysts performed better than monometallic Pt catalyst. The rank order of the content of furans was as follows:3%Pt-3%Al/AC 3%Pt-3%Zr/AC 3%Pt-3%Re/AC 3%Pt-3%Fe/AC 3%Pt-3%Sn/AC 3%Pt-3%Cu/AC 3%Pt/AC. The distribution of furan compounds was sensitive to the second metal, and different Pt-based bimetallic catalysts formed different furan products. This suggests that the second metal in the Pt-based bimetallic catalysts exhibits the potential to influence the reaction pathways for the distribution of furans. Furthermore, a series of Pt-Al/AC catalysts with varing Pt and Al loading were introduced to promote the generation of furans. Comparing with 6%Al and 6%Pt, higher content of furans was obtained by the Pt-Al/AC catalysts. It is revealed that synergy exists between Pt and Al. Among the Pt-Al/AC catalysts, 1%Pt-5%Al/AC,which showed mild acidity, achieved the highest furans content of 70.51 %, followed by 4%Pt-2%Al/AC (65.48 %). The major furan compounds, produced by 1%Pt-5%Al/AC, consisted of furan, 2-methylfuran and 2,5-dimethylfuran, and the selectivity values were 47.95 %, 38.49 % and 12.78 %, respectively.