In this study, a series of Pt/Co2AlO4 catalysts with varying Pt loadings (0.29 wt %, 0.91 wt %, and 2.73 wt %) were prepared via the wet impregnation method and evaluated for the selective hydrogenation of cinnamaldehyde. Among them, the 2.73 wt % Pt/Co2AlO4 catalyst exhibited the highest activity and selectivity. Under the reaction conditions of 60 °C, 2.0 MPa H2, and 2 h, it achieved a cinnamaldehyde (CAL) conversion of 95.7% and a selectivity to cinnamyl alcohol (COL) of 82.8%. Moreover, the catalyst retained its performance over five consecutive recycling tests, demonstrating excellent stability. Based on comprehensive characterization, the superior catalytic behavior of the 2.73 wt % Pt/Co2AlO4 catalyst can be attributed to the following factors: (1) High dispersion of Pt species, with an average particle size of 1.25 ± 0.43 nm; (2) XPS analysis revealed distinct shifts in the binding energies of Co and Pt species, indicating electron transfer from Co to Pt. With increasing Pt loading, the binding energy of Pt further decreased, suggesting enhanced electron density; (3) H2-TPD and H2-TPR results confirmed strong hydrogen adsorption and activation capabilities for this catalyst. Collectively, these features contribute to the outstanding activity, high COL selectivity, and stable recyclability of the 2.73 wt % Pt/Co2AlO4 catalyst in the selective hydrogenation of cinnamaldehyde.
Hong et al. (Thu,) studied this question.