Bimetallic synergy in the PtCo/MgO catalysts for promoting hydrodeoxygenation of guaiacol to cyclohexanol

Bimetallic catalysts composed of a primary hydrogenation metal with an oxyphilic metal often exhibit superior catalytic performance compared to their single-metal counterparts. This study elucidates the bimetallic synergy of cobalt-modified MgO-supported Pt catalysts for promoting the selective hydrodeoxygenation of guaiacol to cyclohexanol. The incorporation of Co significantly enhanced both the activity and cyclohexanol selectivity of the Pt/MgO catalyst, with performance following a volcanic trend relative to Co content. The optimal catalyst, Pt-15Co/MgO, exhibited remarkable performance, achieving 98 % guaiacol conversion and 96 % cyclohexanol selectivity at 180 °C and 1 MPa H 2 pressure. The addition of Co effectively suppressed the growth of Pt particles and improved Pt dispersion. Moreover, Co modification could induce the electron transfer from Co to Pt and promote the reduction of Pt species, leading to the formation of more active Pt 0 sites beneficial for hydrogen activation. The presence of oxyphilic Co also could promote the adsorption of the guaiacol molecules and enhance hydrogen spillover. Pt and Co exhibited a distinct synergistic effect in the hydrodeoxygenation process: Co sites primarily promoted C–O bond cleavage, while Pt sites facilitated hydrogen activation. This complementary cooperation altered the reaction pathway, lowered the activation energy, and thereby improved the catalytic performance. These findings offer a rational strategy for designing highly efficient bimetallic catalysts and provide theoretical guidance for the catalytic conversion of lignin-derived oxygenates.