Guaiacol Hydrodeoxygenation and Hydrogenation over BimetallicPt-M (Nb, W, Zr)/KIT-6 Catalysts with Tunable Acidity

Owing to a high oxygen content, bio-oils from the fastpyrolysis of biomass require upgrading to meet fuel specification standards.Catalytic hydrodeoxygenation (HDO) of bio-oils faces several challenges suchas low hydrocarbon yields, the requirement of high H2partial pressure forcomplete deoxygenation, and catalyst deactivation caused by coking/carbondeposition. In the present work, Pt supported on Nb, W, and Zr-incorporatedKIT-6 materials were prepared, characterized, and tested for the gas-phaseHDO of guaiacol, a widely used model compound of bio-oil. Facile HDO ofguaiacol was observed over a 1 wt % Pt/Nb-KIT-6 catalyst, with similar to 90%conversion and similar to 75% hydrocarbon selectivity under relatively mild hydrogenpartial pressure (0.5 MPa) at 400 degrees C and 33 h-1weight hourly space velocity(WHSV). No significant catalyst deactivation was observed during a 24-hcontinuous run indicating that the mesoporous support provides enhancedcoking resistance. Mechanistic investigations indicate that the tunable acidity of the supports promotes transalkylation reactions,which favor increased aromatic hydrocarbon yields. A plausible reaction mechanism is postulated based on correlating the number ofmetal and acid sites with the measured rates for the individual reaction steps.

Automated summary

In this study, Pt supported on Nb, W, and Zr-incorporated KIT-6 catalysts were prepared and tested for the gas-phase hydrodeoxygenation (HDO) of a model compound of bio-oil. The results showed that the 1 wt % Pt/Nb-KIT-6 catalyst exhibited excellent HDO performance under relatively mild conditions, and the catalyst showed good resistance to coking.