CdS nanocapsules and nanospheres as efficient solar light-driven photocatalysts for degradation of Congo red dye

•Growth mechanism of CdS nanocapsules and nanospheres•Connection between single source precursor stability and morphology of NPs•Effective degradation of Congo red by Cd NPs

CdS-1 (nanosphers) and CdS-2 (nanocapsule), were synthesized via green synthetic route without using any toxic surfactants by thermolysis of bis(4-benzhydrylpiperazine-1-carbodithioate-κ2 S, Sʹ)cadmium(II) (1) and bis (4-benzylpipera-zine-1-carbodithioate-κ2 S, Sʹ)cadmium(II) (2), respectively in the presence of ethylenediamine as a solvent. The nanoparticles were characterized by TEM, XRD, SEM, FT-IR UV–Visible and Fluorescence spectroscopy. The TEM results showed the formation of nanospheres (CdS-1) and nanocapsules (CdS-2) from complexes 1 and 2, respectively. Both CdS nanoparticles (NPs) have hexagonal crystal phase and a band gap value in the visible region as confirmed by the XRD and UV–Visible spectra, respectively. The photoluminescence (PL) data revealed that CdS-2 has longer recombination time of photo-injected electron hole pairs than CdS-1. The similar FT-IR spectra for both CdS NPs, and different HOMO-LUMO gap values for complexes {4.8187 eV (1) and CdS-2 4.7504 eV (2)} as predicted by DFT calculations suggest that stability of complexes play a key role in controlling morphology. Furthermore, the visible light driven photocatalytic degradation of Congo red dye was observed higher for nanocapsules than nanospheres due to a longer recombination time of photo-injected electron hole pairs.

Graphical abstractThis article presents synthesis of CdS nanospheres and nanocapsules from new single source precursors. The nanocapsules were found more efficient visible light-driven photocatalyst than nanospheres due to longer life time of electron-hole pairs recombinationFigure optionsDownload full-size imageDownload as PowerPoint slide