Highly efficient supported bimetallic Au-Pd catalysts for oxidative esterification of methacrolein to methyl methacrylate

Au-Pd alloy particles supported on TiO 2 were synthesized by the sol-immobilized method and their confirmation was achieved through transmission electron microscope (TEM) and energy dispersive spectrometer (EDS) mapping. The samples were subjected to oxidative esterification of methacrolein with methanol to methyl methacrylate (MMA). Notably, a remarkable enhancement of catalytic performance was found in the presence of Pd. Among the samples tested, the sample Au 0.25 Pd 0.75 /TiO 2 exhibited the highest catalytic performance. The interaction between Au and Pd demonstrated a synergistic effect, with Pd contributing to the stability of Au nanoparticles and strengthening the production of active oxygen species, which facilitated the efficient removal of hydrogen from intermediate hemiacetal. Furthermore, a probable reaction mechanism was proposed to explain these observations.