1 research outputs found
MoS<sub>2</sub> Quantum Dots: Effect of Hydrogenation on Surface Stability and H<sub>2</sub>S Release
We
employ density functional theory to investigate effects of hydrogenation
on the energetic stability and electronic properties of triangular
MoS<sub>2</sub> nanoclusters with S-edges. Excess edge sulfur atoms
relative to the bulk stoichiometry along the edges are passivated
by hydrogen atoms. We find that the hydrogen coverage for maximum
stability can be calculated by (<i>n</i> – 2)/2Â(<i>n</i> – 1), where <i>n</i> is the number of
S atoms along an edge. The energetics reveal a preference for the
zigzag arrangement of adsorbed hydrogen atoms on the edges. Our calculations
show vanishing HOMO–LUMO gaps mainly due to the presence of
dangling bonds at the edges and can be considered metal-like. We find
that the activation energy required to release H<sub>2</sub>S lies
in between 0.47 and 0.62 eV, and this value is in good agreement with
the recently reported experimental value