The role of basic sites on magnesia supported Pt catalysts for enhanced selective hydrodeoxygenation of guaiacol to phenol

Modulation of the surface properties on catalyst support for selective hydrogenation with high activity and selectivity is a significant but challenging topic. Herein, we report the promotion of basic sites on MgO surface on the selective hydrodeoxygenation (HDO) of guaiacol to phenol. The results showed that basic MgO support could inhibit the further breaking of C–O bond of generated phenol compared to acidic support, which facilitated the formation of phenol with high selectivity. The catalytic activity of Pt/MgO catalysts was markedly influenced by the concentration and types of basic sites on the catalyst surfaces. The increase in the concentration of basic sites on the catalysts surface led to a linear increase in the conversion of guaiacol, and the selectivity (92 %) of phenol was achieved with >99 % conversion at the conditions of 280 °C and 0.1 MPa H 2 pressure. The characterization of catalysts, combined with the kinetic analysis, demonstrated that the strong basic sites generated by isolated O 2− species on the MgO surface could significantly enhance the adsorption of guaiacol, and improve the dispersion and electronic density of Pt species through the interaction of basic sites and Pt species, thereby further promoting the hydrogen dissociation, which achieved the excellent catalytic performance and stability by the dual active sites of basic sites and Pt sites. This study provides a promising strategy for the design of supported metal catalysts with improved surface basic sites for the selective HDO reactions of oxygenates.