Shell thickness-driven photocatalytic behavior of PANI/CdS/ZnS core/shell nanocomposites

Cadmium sulphide/zinc sulphide nanocomposites embedded in polyaniline (PANI/CdS/ZnS) were prepared by a simple two-step sol-gel method. The as-synthesized nanocomposites were characterized using different spectroscopic and structural characterization techniques. The optical properties, structure, composition, and morphology of the as-prepared nanocomposites were studied using UV-Vis spectrophotometry, photoluminescence spectrophotometry (PL), x-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive x-ray spectroscopy (EDAX/EDS), and transmission electron microscopy (TEM). The synthesized nanocomposite was found to be of spherical shape, with an average particle size in the nanometer range. The photocatalytic activity of the prepared nanocomposite was examined toward the degradation of an organic dye as a model for wastewater treatment. The PANI/CdS/ZnS nanocomposite exhibited prominent catalytic activity toward the tested dye, methyl orange (MO), with a degradation efficiency of \ensuremath{\sim}96.4% in a short reaction time of 50 mins for the sample with the highest shell concentration. Kinetic study of the photocatalytic degradation reactions was performed and showed pseudo-first-order kinetics.