Plant Arabinogalactan Gum Synthesized Palladium Nanoparticles: Characterization and Properties

Abstract

An ecofriendly and facile autoclaving method was devised for palladium nanoparticle synthesis utilizing biocompatible, biodegradable, nontoxic, renewable plant arabinogalactan gum, tragacanth. The formed nanoparticles were characterized with UV–Visible spectroscopy (UV–Vis), zeta sizer, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The formation of dark brown colour and wide continuous spectra in UV–Vis confirmed the formation of palladium nanoparticles (Pd NP). Also, various reaction conditions such as concentrations of reductant, metal precursor and reaction time were optimized to obtain stable Pd NP preparation. Based on UV–Vis and zeta sizer data, the optimized preparation was at 0.5% gum, 0.5 mM palladium chloride and 30 min of autoclaving. The Pd NP were predominantly polydisperse, anisotropic including triangles, tetragons, pentagons and hexagons. The particle size ranged from 5 to 31.2 nm and the mean particle size was about 14.3 ± 7.2 nm. The NP exhibited face centered cubic (fcc) crystal structure and FTIR confirms the role of sugars and proteins in reduction and stabilization. Further, the characterized NP were explored for their antibacterial, antifungal, antioxidant, catalytic and peroxidase mimicking properties. The biogenic Pd NP were non antimicrobial and exhibited significant antioxidant and dye decolourizing catalytic activities. The current investigation can be exploited for environmental remediation of toxic dyes and pigments. In addition, the peroxidase mimicking activity of Pd NP was optimized with respect to pH, temperature and concentrations of substrates. Especially, the superior peroxidase activity of the NP can have vast utilization in colorimetric detection of hydrogen peroxide in various matrices such as water, milk, honey and other food products.