Green synthesis of Pd nanoparticles supported on modified Nonpareil almond shell using almond hull extract: a beneficial nanocatalyst for convenient reduction of organic dyes

In this investigation, palladium nanoparticles were synthesized by green and inexpensive method using Nonpareil almond hull, as a reducing and stabilizing agent without using any toxic solvent or capping agents. In this protocol, two separate methods were used to immobilize Pd NPs on the surface of green-waste Nonpareil almond shell (NAS) and modified Nonpareil almond shell was obtained as an environmentally benign support. The green synthesized nanocatalysts were characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET), and transform electron microscopy (TEM). TEM images revealed that the Pd NPs immobilized on modified Nonpareil almond shell are spherical particles with average size of less than 20 nm without any agglomeration. In order to investigate the catalytic activity of green synthesized Nanocatalyst, it was used in the reduction of Methylene Blue (MB), Rhodamine 6G (R6G) and Methyl Orange (MO) at room temperature. The results showed that the modified nanocatalyst had a high catalytic activity in the reduction of these organic dyes. In addition, the nanocatalyst can be easily recycled and reused several times without losing its activity.