One-pot sonochemical synthesis of CdS nanoparticles: photocatalytic and electrical properties

Abstract

CdS nanoparticles (NPs) are synthesized by sonochemical method using tryptophan as a capping agent. The synthesis process is of one step, using biocompatible capping agent, which is nontoxic. The synthesized NPs are characterized by UV–Vis absorption, fluorescence, FTIR, XRD, TGA, DLS, SEM and TEM. The size of NPs is below 10 nm, as observed from XRD and TEM characterizations. Photocatalytic degradation of methyl orange (MO) dye by the CdS NPs as photocatalysts under sunlight irradiation has been studied. The kinetics of catalysis of synthesized CdS NPs with MO dye follows pseudo-first-order kinetics with reasonable apparent rate constants. A variation of dielectric constant as a function of frequencies of an alternating electric field has been observed with the prepared tryptophan-capped CdS NPs deposited at different concentrations. The electric conductivity of CdS NPs is found to increases with the concentration of tryptophan.