We have studied using scanning tunneling microscopy (STM) the atomic-scale
realm of molybdenum disulfide (MoS2) nanoclusters, which are of interest as
a model system in hydrodesulfurization catalysis. The STM gives the first
real space images of the shape and edge structure of single-layer MoS2 nano
particles synthesized on Au(lll), and establishes a new picture of the acti
ve edge sires of the nanoclusters. The results demonstrate a way to get det
ailed atomic-scale information on catalysts in general.