Synthesis of Pd/Fe3O4 nanoparticle-based catalyst for the cross-coupling of acrylic acid with iodobenzene

In this study, catalyst Pd/Fe3O4 based on magnetic body with the size of 8 nm was prepared and characterized by TEM, HRTEM, XPS and VSM methods. The results show that Pd0 atom produced after the first reduction is bound to APTS-coated Fe3O4 nanoparticles by the coordination of -NH2 ligand with Pd0 and then grows into bigger clusters with the increase in the reduction times. However, when the reduction is performed for more than three times, Pd0 atom produced in subsequent reduction is dispersed in aqueous solution instead of depositing around preexisting Pd0 atom or clusters. In order to further investigate its catalytic behavior, Heck reaction of the cross-coupling of acrylic acid with iodobenzene was employed. The activity measurements show that the product yield decreased greatly from 81% for the first times to 53% for the fifth times and then kept constant in the subsequent re-use. One of the important reasons for this is that the catalyst aggregates into big particle and becomes more difficult to be dispersed with the increase in reaction times. In a word, this preliminary work provides the primary understanding of the catalyst based on Fe3O4 nanoparticles and its application in Heck reaction.