Abstract: To elucidate the synergistic mechanism of bimetallic supported catalysts in the hydrodeoxygenation of guaiacol, this study constructed Ni/Al2O3 and Ni-Fe/Al2O3 models based on density functional theory to systematically investigate the adsorption activation and reaction pathways of guaiacol. The results indicate that Fe doping significantly enhances the metal-support interaction, thereby improving the structural stability of the catalyst. Guaiacol preferentially undergoes demethylation on both catalysts; however, the introduction of Fe specifically activates the methoxy C-O bond, reducing its cleavage energy barrier from 1.20 eV to 0.84 eV. This shifts the rate-determining step of the HDO reaction from demethylation to the hydrogenation of intermediate products. Regarding the subsequent transformation of the catechol intermediate, while Fe doping does not alter the primary pathway of preferential dehydroxylation, it generally increases the energy barriers for the elementary steps. Electronic structure analysis reveals that the high oxophilicity of Fe drives electron migration from the metal cluster to the support, resulting in reduced electron density within the metal cluster. This electronic reconstruction effect promotes C-O bond activation (deoxygenation) while inhibiting benzene ring hydrogenation activity, providing a theoretical basis for understanding the high selectivity deoxygenation mechanism of non-noble metal catalysts.

Key words: Guaiacol, Ni-Fe cluster, Al₂O₃, Hydrodeoxygenation, Density functional theory