A Comparative Study on Visible Light Induced Photocatalytic Activity of MWCNTs Decorated Sulfide Based (ZnS & CdS) Nano Photocatalysts

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Sulfide-based semiconductor nano photocatalysts like ZnS and CdS of different particle sizes were prepared by chemical method. These photo catalysts show an excellent photo catalytic activity in the visible region due to their appropriate energy bandgap (Eg). Multiwalled carbon nanotubes (MWCNTs) intercalated sulfide-based photocatalysts like ZnS/MWCNTs and CdS/MWCNTs composites enhance photocatalytic response in comparison to ZnS and CdS NCs. The photocatalytic activity of MWCNTs intercalated ZnS and CdS composites were studied via decomposition of organic pollutant. The obtained particle size of the CdS, ZnS, MWNT/CdS, and MWCNT/ZnS crystals were found to be 32.0 nm, 8.48 nm, 38.5 nm, and 13.18 nm, respectively. The FTIR characteristics of MWCNT/ZnS and MWCNT/CdS composites represent bands at 1637 and 3313 cm-1 in presence of methylene blue. The intense band at 1637 cm-1 could be the stretching vibrations of the C=O group and the other intense band at 3313cm-1 was assigned to the stretching vibration of O-H group. The reduction in optical band gap for MWCNTs/CdS (2.39eV) over CdS (2.44eV) and MWCNT/ZnS (3.77 eV) over ZnS (3.88 eV) was observed. Enhancement in photocatalytic activity was verified along with pseudo-first-order chemical kinetics.