Synthesis and application of CdS nanoparticles-decorated core-shell Ag@Ni nanohybrids for visible-light spectrophotometric assay of sulfide in aqueous sample.

Novel Ag@Ni nanosphere decorated with CdS NPs (Ag@Ni-CdS NCs) was synthesized by one step chemical synthesis method. The fabricated NCs were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), fourier transfer infra-red spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), zeta sizer and particle size analyzer. TEM and XRD confirmed the Ag in core and Ni in shell for the effective formation of Ag@Ni core shell nanosphere. EDAX and XPS spectra of NCs confirms the formation of Ag@Ni-CdS NCs. Zeta potential and particle size of the NCs was found to be 29.5 ± 1.5 mV and 24 ± 1 nm respectively. The complete loss in the peak intensity of Ag@Ni-CdS NCs (localized surface plasmon resonance (LSPR)) at ∼410 nm in presence of S ions was observed which indicates its selective detection towards S ions. The sulfide ion sensing by Ag@Ni-CdS NCs was due to the successive oxidation of Ag results in the formulation of Ag ions in the system, which causes the diminishing of LSPR band of NCs. The limit of detection (LOD) of S ions by Ag@Ni-CdS NCs was calculated to be of 2.66 nM. The combination of CdS NPs with core-shell Ag@Ni nanosphere guides a promising strategy for S ions detection from environmental polluted samples.