Magnetic polyaniline-chitosan nanocomposite decorated with palladium nanoparticles for enhanced catalytic reduction of 4-nitrophenol

In this article, palladium (Pd) nanoparticles were deposited on a smart surface composed of a synthetic polymer, a natural polymer and a magnetic inorganic material, polyaniline (PANI), chitosan (CS) and magnetite (Fe₃O₄), respectively to form Pd@PANI-CS-Fe₃O₄ nanocomposite. The parent magnetic nanocomposite was prepared via in situ polymerization of aniline in the presence of CS. Exploitation of the polymerization side product, ferrous chloride (FeCl₂), produced Fe₃O₄ that imparted the nanocomposite with magnetic character. Pd nanoparticles were then stabilized @ the nanocomposite via reduction of Pd ions. X-ray electron diffraction (XRD), Fourier transform infrared (FTIR), transmission electron microscope (TEM), selected area electron diffraction (SAED) as well as energy dispersive X-ray (EDX) were employed to characterize Pd@PANI-CS-Fe₃O₄ nanocomposite. In addition, vibrating sample magnetometer (VSM) was used to investigate the magnetic property of Pd@PANI-CS-Fe₃O₄ nanocomposite. The reduction of the toxic 4-nitrophenol (4-NP) to a safer form, 4-amino phenol (4-AP), was employed to examine the catalytic efficacy of Pd@PANI-CS-Fe₃O₄ nanocomposite as a heterogenous nanocatalyst. Pd@PANI-CS-Fe₃O₄ represented a high kinetic rate up to 0.222 min⁻¹.