Bifunctional Pt-Re Catalysts in Hydrodeoxygenation of Isoeugenol as a Model Compound for Renewable Jet Fuel Production

Bimetallic platinum–rhenium catalysts supported on activated carbon were tested for the hydrodeoxygenation (HDO) of isoeugenol at 250 °C and 30 bar of H2 in a batch reactor. The catalysts were characterized by inductively coupled plasma atomic emission spectrometry (ICP-IES), N2 physisorption, electron microscopy (high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), transmission electron microscopy (TEM)), temperature-programmed reduction, X-ray absorption spectroscopy (X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS)), and temperature-programmed desorption of ammonia. Bimetallic catalysts containing Pt and Re were much more active than monometallic Pt/C and Re/C. Complete isoeugenol conversion, high propylcyclohexane yield (99%), and a high liquid-phase mass balance (77%) were obtained for the catalyst with the highest Re loading, Pt–Re(1:5)/C. Such high activity is attributed to a synergistic effect between the reduced Pt and the Re-oxide species, as both metal active sites and oxygen vacancies are required for HDO. The apparent activation energy for the HDO of isoeugenol with Pt–Re(1:5)/C was 44 kJ/mol.