  The design and development of inexpensive highly efficient electrocatalysts
for hydrogen production, underpins several emerging clean-energy technologies.
In this work, for the first time, molybdenum disulfide (MoS2) nanodots have
been synthesized by ionic liquid assisted grinding exfoliation of bulk
platelets and isolated by sequential centrifugation. The nanodots have a
thickness of up to 7 layers (4 nm) and an average lateral size smaller than 20
nm. Detailed structural characterization established that the nanodots retained
the crystalline quality and low oxidation states of the bulk material. The
small lateral size and reduced number of layers provided these nanodots with an
easier path for the electron transport and plentiful active sites for the
catalysis of hydrogen evolution reaction (HER) in acidic electrolyte. The MoS2
nanodots exhibited good durability and a Tafel slope of 61 mVdec-1 with an
estimated onset potential of -0.09 V vs RHE, which are considered among the
best values achieved for 2H phase. It is envisaged that this work may provide a
simplistic route to synthesize a wide range of 2D layered nanodots that have
applications in water splitting and other energy related technologies.
KEYWORDS: MoS2 nanosheets, hydrogen evolution reaction, electrocatalysis,
edges, nanodots, ionic liquid exfoliation, water splitting
