Synergistic Effect in Vapor Phase Hydrodeoxygenation on USY Zeolite Supported Ir-Pt Catalyst: Role of Pentacoordinated Al3+ Ions

The positive role of pentacoordinated Al-V sites on the catalyst behavior was evidenced in the vapor phase hydrodeoxygenation (HDO) of phenol over Ir-, Pt-, and Pt-Ir catalysts supported on USY and ZSM-5. All catalysts showed bifunctionality in the HDO reaction at 310 degrees C and 30 bar H-2, the more acidic USY zeolite being more efficient as a support than ZSM-5, and the metal function decreasing in the order Ir-Pt > Pt >> Ir. The superior activity of Ir-Pt/USY was attributed to the cumulative effects of the support acidity, the smaller zeolite crystal size, the higher amount of unsaturated Al-V sites, and the synergy between acid and metal sites. The promotion of Pt with Ir improved the reducibility of platinum, the catalyst's overall oxophilicity, and its active phase dispersion.

Automated summary

The positive role of pentacoordinated Al-V sites in the catalyst behavior was evidenced in the vapor phase hydrodeoxygenation (HDO) of phenol. The USY zeolite was more efficient than ZSM-5, and the superior activity of Ir-Pt/USY was attributed to the cumulative effects of various factors working in synergy.