Biosynthesis of silver nanocatalyst and its application for the efficient hydrogenation of nitroarenes

The utilization of plant extracts for the synthesis of silver nanoparticles (Ag-NPs) has attracted attention from all over the world due to its unique physicochemical characteristics and significance in the field of environment. Here, Nepal pepper fruit extract was successfully employed to synthesize Ag-NPs. As obtained, Nepal pepper-mediated Ag-NPs were employed for the catalytic conversion of nitroarenes including 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), 2-nitroaniline (2-NA), and 2,4,6-trinitrophenol (2,4,6-TNP), into their corresponding amino derivatives using sodium borohydride (NaBH4). The Ag-NPs were analyzed using UV-visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-rays (EDX), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), X-rays Diffraction (XRD), and Zeta potential. TEM micrographs revealed the prepared Ag-NPs were predominantly spherical, with an average diameter of 13.9 nm. DLS and zeta potential studies showed stable small-size Ag-NPs of an average size of 6.8 nm. Ag-NPs elucidate outstanding reduction efficiency against 4-NP, 2-NP, 2-NA, and 2,4,6-TNP with rate constants of 1.71 x 10-3 s- 1, 2.32 x 10-3 s- 1, 2.88 x 10-3 s- 1, and 1.54 x 10-3 s- 1, respectively. Additionally, stability and reusability of Ag-NPs revealed stability for up to 15 days and excellent recyclability with small activity loss. This study constittutes an environmentally friendly approach for the synthesis of Ag-NP nanoparticles and their applications in improved organic chemical reduction rates and transformations.