Tannic acid, as a humic-like substance with phenolic hydroxyl and carbonyl functional groups, can modify surface of Fe3O4 NPs. Moreover, it can improve surface properties and capacity of Fe3O4 for adsorption and reduction of palladium ions through complexing with them, in aqueous solutions. Therefore, Fe3O4@TA NPs have potentials of reducing, stabilizing and immobilizing palladium nano particles to generate novel magnetic palladium nanocatalysts. Inductively coupled plasma (ICP), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectrum (EDS), vibrating sample magnetometer (VSM) and Fourier transform infrared (FTIR) methods unraveled the catalyst properties. Investigation of Fe3O4@TA/Pd NPs performance illustrated its recycle nature and high catalytic activity towards Suzuki-Miyaura cross-coupling reactions and reduction of 4-nitrophenol (4-NP), at room temperature
