Preparation and Characterization of Metallic Pd Nanoparticles Supported on ZnWO4 Nanorods for Enhanced Photocatalytic Degradation of Rhodamine B Under UV Light Irradiation

The metallic Pd nanoparticles were supported on the surface of ZnWO₄ nanorods to form heterojunction Pd/ZnWO₄ nanocomposites by microwave-assisted method using ethylene glycol as reducing regent. The phase, morphologies, atomic vibration, surface area and oxidation state of element of pure ZnWO₄ sample and heterojunction Pd/ZnWO₄ nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, BET surface area analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), respectively. The analytic results confirmed the formation of heterojunction between the face centered cubic (FCC) metallic Pd nanoparticles supported on surface of monoclinic ZnWO₄ nanorods. FTIR and Raman analysis of samples showed the stretching and bending of Zn–O–W, W–O, and Zn–O vibrations in ZnO₆ and WO₆ octahedron of ZnWO₄ lattices. The surface area of ZnWO₄ and heterojunction 5% Pd/ZnWO₄ nanocomposites were 10.47 and 6.09 m²/g. The effect of weight of Pd loading on surface of one-dimensional ZnWO₄ nanorods on photocatalytic degradation of rhodamine B under UV light irradiation has been studied and discussed in this research. It found that the heterojunction 5% Pd/ZnWO₄ nanocomposites showed the highest photocatalytic activity of 98.54% RhB degradation within 180 min under UV light irradiation due to reduce the recombination of photogenerated electron–hole pairs by formation Schottky barrier at the metal–semiconductor interface.