  In the present paper, we investigate the effect of plasmonic Au nanoparticles
(NPs) decoration on the photocatalytic efficiency of MoS$_2$ nanosheets. The Au
NPs are grown on the surface of chemically exfoliated MoS$_2$ nanosheets by
chemical reduction method. Au-MoS$_2$ nanostructures (NSs) are characterized by
X-ray diffractometer, Raman spectrometer, absorption spectrophotometer, and
transmission electron microscopy. 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 photo degradation efficiencies between 30% to 46.9% for MR and 23.3% to
44% for MB, with varying exposure times from 30 to 120 min, respectively.
However, Au-MoS$_2$ NSs with maximum Au NPs concentration show enhanced
degradation efficiency from 70.2 to 96.7% for MR, and from 65.2 to 94.3% for
MB. The manifold enhancement of degradation efficiency for both the dyes with
Au-MoS$_2$ NSs may be attributed to the presence of Au NPs acting as charge
trapping sites in the NSs. We believe this study would have potential
application in battling the ill-effects of environmental degradation, which
poses a major threat to humans as well as biodiversity.
