Enhanced photocatalytic activity of plasmonic Au nanoparticles incorporated MoS2 nanosheets for degradation of organic dyes

In the present paper, we have investigated the effect of plasmonic gold nanoparticles (Au NPs) decoration on the photocatalytic efficiency of molybdenum disulfide (MoS 2 ) nanosheets. The Au NPs are grown on the surfaces of chemically exfoliated MoS 2 nanosheets by chemical reduction method with four different concentrations. The resulting Au-MoS 2 nanostructures (NSs) are then characterized by X-ray diffractometer, Raman spectrometer, absorption spectrophotometer, field emission scanning electron microscopy, energy dispersive X-ray, and transmission electron microscopy (TEM). Sizes of the exfoliated MoS 2 nanosheets are ~ 700 nm. In addition, the sizes of Au nanoparticles increase from 8.02 ± 2.03 nm to 9.81 ± 3.18 nm with the increase in concentrations of Au ions, as revealed by TEM imaging. Exfoliated MoS 2 and Au-MoS 2 NSs are used to study the photocatalytic degradation of organic dyes, methyl red (MR) and methylene blue (MB). Under UV–Visible light irradiation, pristine MoS 2 shows photodegradation efficiencies in the range of 30.0% to 46.9% for MR, and 23.3% to 44.0% for MB, with varying exposure times of 30 to 120 min. However, Au-MoS 2 NSs with the sets having maximum Au NPs concentrations, show enhanced degradation efficiencies from 70.2 to 96.7% for MR, and from 65.2 to 94.3% for MB. The degradation rate constants vary from − 0.5660 to − 1.5551 min −1 for MR dye, and vary from − 0.3587 to − 1.2614 min −1 for MB dye. The multi-fold enhancements of degradation efficiencies for both the dyes with Au-MoS 2 NSs, can be attributed to the presence of Au NPs acting as charge trapping sites in the NSs. We believe this type of study could provide a way to battle the ill-effects of environmental degradation that pose a major threat to humans as well as biodiversity. This study can be further extended to other semiconducting materials in conjugation with two dimensional materials for photocatalytic treatment of polluted water.